diff options
Diffstat (limited to 'drivers/mtd/nand/raw/gpmi-nand/gpmi-lib.c')
| -rw-r--r-- | drivers/mtd/nand/raw/gpmi-nand/gpmi-lib.c | 1510 |
1 files changed, 1510 insertions, 0 deletions
diff --git a/drivers/mtd/nand/raw/gpmi-nand/gpmi-lib.c b/drivers/mtd/nand/raw/gpmi-nand/gpmi-lib.c new file mode 100644 index 0000000..9778724 --- /dev/null +++ b/drivers/mtd/nand/raw/gpmi-nand/gpmi-lib.c @@ -0,0 +1,1510 @@ +/* + * Freescale GPMI NAND Flash Driver + * + * Copyright (C) 2008-2011 Freescale Semiconductor, Inc. + * Copyright (C) 2008 Embedded Alley Solutions, Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ +#include <linux/delay.h> +#include <linux/clk.h> +#include <linux/slab.h> + +#include "gpmi-nand.h" +#include "gpmi-regs.h" +#include "bch-regs.h" + +static struct timing_threshold timing_default_threshold = { + .max_data_setup_cycles = (BM_GPMI_TIMING0_DATA_SETUP >> + BP_GPMI_TIMING0_DATA_SETUP), + .internal_data_setup_in_ns = 0, + .max_sample_delay_factor = (BM_GPMI_CTRL1_RDN_DELAY >> + BP_GPMI_CTRL1_RDN_DELAY), + .max_dll_clock_period_in_ns = 32, + .max_dll_delay_in_ns = 16, +}; + +#define MXS_SET_ADDR 0x4 +#define MXS_CLR_ADDR 0x8 +/* + * Clear the bit and poll it cleared. This is usually called with + * a reset address and mask being either SFTRST(bit 31) or CLKGATE + * (bit 30). + */ +static int clear_poll_bit(void __iomem *addr, u32 mask) +{ + int timeout = 0x400; + + /* clear the bit */ + writel(mask, addr + MXS_CLR_ADDR); + + /* + * SFTRST needs 3 GPMI clocks to settle, the reference manual + * recommends to wait 1us. + */ + udelay(1); + + /* poll the bit becoming clear */ + while ((readl(addr) & mask) && --timeout) + /* nothing */; + + return !timeout; +} + +#define MODULE_CLKGATE (1 << 30) +#define MODULE_SFTRST (1 << 31) +/* + * The current mxs_reset_block() will do two things: + * [1] enable the module. + * [2] reset the module. + * + * In most of the cases, it's ok. + * But in MX23, there is a hardware bug in the BCH block (see erratum #2847). + * If you try to soft reset the BCH block, it becomes unusable until + * the next hard reset. This case occurs in the NAND boot mode. When the board + * boots by NAND, the ROM of the chip will initialize the BCH blocks itself. + * So If the driver tries to reset the BCH again, the BCH will not work anymore. + * You will see a DMA timeout in this case. The bug has been fixed + * in the following chips, such as MX28. + * + * To avoid this bug, just add a new parameter `just_enable` for + * the mxs_reset_block(), and rewrite it here. + */ +static int gpmi_reset_block(void __iomem *reset_addr, bool just_enable) +{ + int ret; + int timeout = 0x400; + + /* clear and poll SFTRST */ + ret = clear_poll_bit(reset_addr, MODULE_SFTRST); + if (unlikely(ret)) + goto error; + + /* clear CLKGATE */ + writel(MODULE_CLKGATE, reset_addr + MXS_CLR_ADDR); + + if (!just_enable) { + /* set SFTRST to reset the block */ + writel(MODULE_SFTRST, reset_addr + MXS_SET_ADDR); + udelay(1); + + /* poll CLKGATE becoming set */ + while ((!(readl(reset_addr) & MODULE_CLKGATE)) && --timeout) + /* nothing */; + if (unlikely(!timeout)) + goto error; + } + + /* clear and poll SFTRST */ + ret = clear_poll_bit(reset_addr, MODULE_SFTRST); + if (unlikely(ret)) + goto error; + + /* clear and poll CLKGATE */ + ret = clear_poll_bit(reset_addr, MODULE_CLKGATE); + if (unlikely(ret)) + goto error; + + return 0; + +error: + pr_err("%s(%p): module reset timeout\n", __func__, reset_addr); + return -ETIMEDOUT; +} + +static int __gpmi_enable_clk(struct gpmi_nand_data *this, bool v) +{ + struct clk *clk; + int ret; + int i; + + for (i = 0; i < GPMI_CLK_MAX; i++) { + clk = this->resources.clock[i]; + if (!clk) + break; + + if (v) { + ret = clk_prepare_enable(clk); + if (ret) + goto err_clk; + } else { + clk_disable_unprepare(clk); + } + } + return 0; + +err_clk: + for (; i > 0; i--) + clk_disable_unprepare(this->resources.clock[i - 1]); + return ret; +} + +#define gpmi_enable_clk(x) __gpmi_enable_clk(x, true) +#define gpmi_disable_clk(x) __gpmi_enable_clk(x, false) + +int gpmi_init(struct gpmi_nand_data *this) +{ + struct resources *r = &this->resources; + int ret; + + ret = gpmi_enable_clk(this); + if (ret) + return ret; + ret = gpmi_reset_block(r->gpmi_regs, false); + if (ret) + goto err_out; + + /* + * Reset BCH here, too. We got failures otherwise :( + * See later BCH reset for explanation of MX23 handling + */ + ret = gpmi_reset_block(r->bch_regs, GPMI_IS_MX23(this)); + if (ret) + goto err_out; + + + /* Choose NAND mode. */ + writel(BM_GPMI_CTRL1_GPMI_MODE, r->gpmi_regs + HW_GPMI_CTRL1_CLR); + + /* Set the IRQ polarity. */ + writel(BM_GPMI_CTRL1_ATA_IRQRDY_POLARITY, + r->gpmi_regs + HW_GPMI_CTRL1_SET); + + /* Disable Write-Protection. */ + writel(BM_GPMI_CTRL1_DEV_RESET, r->gpmi_regs + HW_GPMI_CTRL1_SET); + + /* Select BCH ECC. */ + writel(BM_GPMI_CTRL1_BCH_MODE, r->gpmi_regs + HW_GPMI_CTRL1_SET); + + /* + * Decouple the chip select from dma channel. We use dma0 for all + * the chips. + */ + writel(BM_GPMI_CTRL1_DECOUPLE_CS, r->gpmi_regs + HW_GPMI_CTRL1_SET); + + gpmi_disable_clk(this); + return 0; +err_out: + gpmi_disable_clk(this); + return ret; +} + +/* This function is very useful. It is called only when the bug occur. */ +void gpmi_dump_info(struct gpmi_nand_data *this) +{ + struct resources *r = &this->resources; + struct bch_geometry *geo = &this->bch_geometry; + u32 reg; + int i; + + dev_err(this->dev, "Show GPMI registers :\n"); + for (i = 0; i <= HW_GPMI_DEBUG / 0x10 + 1; i++) { + reg = readl(r->gpmi_regs + i * 0x10); + dev_err(this->dev, "offset 0x%.3x : 0x%.8x\n", i * 0x10, reg); + } + + /* start to print out the BCH info */ + dev_err(this->dev, "Show BCH registers :\n"); + for (i = 0; i <= HW_BCH_VERSION / 0x10 + 1; i++) { + reg = readl(r->bch_regs + i * 0x10); + dev_err(this->dev, "offset 0x%.3x : 0x%.8x\n", i * 0x10, reg); + } + dev_err(this->dev, "BCH Geometry :\n" + "GF length : %u\n" + "ECC Strength : %u\n" + "Page Size in Bytes : %u\n" + "Metadata Size in Bytes : %u\n" + "ECC Chunk Size in Bytes: %u\n" + "ECC Chunk Count : %u\n" + "Payload Size in Bytes : %u\n" + "Auxiliary Size in Bytes: %u\n" + "Auxiliary Status Offset: %u\n" + "Block Mark Byte Offset : %u\n" + "Block Mark Bit Offset : %u\n", + geo->gf_len, + geo->ecc_strength, + geo->page_size, + geo->metadata_size, + geo->ecc_chunk_size, + geo->ecc_chunk_count, + geo->payload_size, + geo->auxiliary_size, + geo->auxiliary_status_offset, + geo->block_mark_byte_offset, + geo->block_mark_bit_offset); +} + +/* Configures the geometry for BCH. */ +int bch_set_geometry(struct gpmi_nand_data *this) +{ + struct resources *r = &this->resources; + struct bch_geometry *bch_geo = &this->bch_geometry; + unsigned int block_count; + unsigned int block_size; + unsigned int metadata_size; + unsigned int ecc_strength; + unsigned int page_size; + unsigned int gf_len; + int ret; + + if (common_nfc_set_geometry(this)) + return !0; + + block_count = bch_geo->ecc_chunk_count - 1; + block_size = bch_geo->ecc_chunk_size; + metadata_size = bch_geo->metadata_size; + ecc_strength = bch_geo->ecc_strength >> 1; + page_size = bch_geo->page_size; + gf_len = bch_geo->gf_len; + + ret = gpmi_enable_clk(this); + if (ret) + return ret; + + /* + * Due to erratum #2847 of the MX23, the BCH cannot be soft reset on this + * chip, otherwise it will lock up. So we skip resetting BCH on the MX23. + * On the other hand, the MX28 needs the reset, because one case has been + * seen where the BCH produced ECC errors constantly after 10000 + * consecutive reboots. The latter case has not been seen on the MX23 + * yet, still we don't know if it could happen there as well. + */ + ret = gpmi_reset_block(r->bch_regs, GPMI_IS_MX23(this)); + if (ret) + goto err_out; + + /* Configure layout 0. */ + writel(BF_BCH_FLASH0LAYOUT0_NBLOCKS(block_count) + | BF_BCH_FLASH0LAYOUT0_META_SIZE(metadata_size) + | BF_BCH_FLASH0LAYOUT0_ECC0(ecc_strength, this) + | BF_BCH_FLASH0LAYOUT0_GF(gf_len, this) + | BF_BCH_FLASH0LAYOUT0_DATA0_SIZE(block_size, this), + r->bch_regs + HW_BCH_FLASH0LAYOUT0); + + writel(BF_BCH_FLASH0LAYOUT1_PAGE_SIZE(page_size) + | BF_BCH_FLASH0LAYOUT1_ECCN(ecc_strength, this) + | BF_BCH_FLASH0LAYOUT1_GF(gf_len, this) + | BF_BCH_FLASH0LAYOUT1_DATAN_SIZE(block_size, this), + r->bch_regs + HW_BCH_FLASH0LAYOUT1); + + /* Set *all* chip selects to use layout 0. */ + writel(0, r->bch_regs + HW_BCH_LAYOUTSELECT); + + /* Enable interrupts. */ + writel(BM_BCH_CTRL_COMPLETE_IRQ_EN, + r->bch_regs + HW_BCH_CTRL_SET); + + gpmi_disable_clk(this); + return 0; +err_out: + gpmi_disable_clk(this); + return ret; +} + +/* Converts time in nanoseconds to cycles. */ +static unsigned int ns_to_cycles(unsigned int time, + unsigned int period, unsigned int min) +{ + unsigned int k; + + k = (time + period - 1) / period; + return max(k, min); +} + +#define DEF_MIN_PROP_DELAY 5 +#define DEF_MAX_PROP_DELAY 9 +/* Apply timing to current hardware conditions. */ +static int gpmi_nfc_compute_hardware_timing(struct gpmi_nand_data *this, + struct gpmi_nfc_hardware_timing *hw) +{ + struct timing_threshold *nfc = &timing_default_threshold; + struct resources *r = &this->resources; + struct nand_chip *nand = &this->nand; + struct nand_timing target = this->timing; + bool improved_timing_is_available; + unsigned long clock_frequency_in_hz; + unsigned int clock_period_in_ns; + bool dll_use_half_periods; + unsigned int dll_delay_shift; + unsigned int max_sample_delay_in_ns; + unsigned int address_setup_in_cycles; + unsigned int data_setup_in_ns; + unsigned int data_setup_in_cycles; + unsigned int data_hold_in_cycles; + int ideal_sample_delay_in_ns; + unsigned int sample_delay_factor; + int tEYE; + unsigned int min_prop_delay_in_ns = DEF_MIN_PROP_DELAY; + unsigned int max_prop_delay_in_ns = DEF_MAX_PROP_DELAY; + + /* + * If there are multiple chips, we need to relax the timings to allow + * for signal distortion due to higher capacitance. + */ + if (nand->numchips > 2) { + target.data_setup_in_ns += 10; + target.data_hold_in_ns += 10; + target.address_setup_in_ns += 10; + } else if (nand->numchips > 1) { + target.data_setup_in_ns += 5; + target.data_hold_in_ns += 5; + target.address_setup_in_ns += 5; + } + + /* Check if improved timing information is available. */ + improved_timing_is_available = + (target.tREA_in_ns >= 0) && + (target.tRLOH_in_ns >= 0) && + (target.tRHOH_in_ns >= 0); + + /* Inspect the clock. */ + nfc->clock_frequency_in_hz = clk_get_rate(r->clock[0]); + clock_frequency_in_hz = nfc->clock_frequency_in_hz; + clock_period_in_ns = NSEC_PER_SEC / clock_frequency_in_hz; + + /* + * The NFC quantizes setup and hold parameters in terms of clock cycles. + * Here, we quantize the setup and hold timing parameters to the + * next-highest clock period to make sure we apply at least the + * specified times. + * + * For data setup and data hold, the hardware interprets a value of zero + * as the largest possible delay. This is not what's intended by a zero + * in the input parameter, so we impose a minimum of one cycle. + */ + data_setup_in_cycles = ns_to_cycles(target.data_setup_in_ns, + clock_period_in_ns, 1); + data_hold_in_cycles = ns_to_cycles(target.data_hold_in_ns, + clock_period_in_ns, 1); + address_setup_in_cycles = ns_to_cycles(target.address_setup_in_ns, + clock_period_in_ns, 0); + + /* + * The clock's period affects the sample delay in a number of ways: + * + * (1) The NFC HAL tells us the maximum clock period the sample delay + * DLL can tolerate. If the clock period is greater than half that + * maximum, we must configure the DLL to be driven by half periods. + * + * (2) We need to convert from an ideal sample delay, in ns, to a + * "sample delay factor," which the NFC uses. This factor depends on + * whether we're driving the DLL with full or half periods. + * Paraphrasing the reference manual: + * + * AD = SDF x 0.125 x RP + * + * where: + * + * AD is the applied delay, in ns. + * SDF is the sample delay factor, which is dimensionless. + * RP is the reference period, in ns, which is a full clock period + * if the DLL is being driven by full periods, or half that if + * the DLL is being driven by half periods. + * + * Let's re-arrange this in a way that's more useful to us: + * + * 8 + * SDF = AD x ---- + * RP + * + * The reference period is either the clock period or half that, so this + * is: + * + * 8 AD x DDF + * SDF = AD x ----- = -------- + * f x P P + * + * where: + * + * f is 1 or 1/2, depending on how we're driving the DLL. + * P is the clock period. + * DDF is the DLL Delay Factor, a dimensionless value that + * incorporates all the constants in the conversion. + * + * DDF will be either 8 or 16, both of which are powers of two. We can + * reduce the cost of this conversion by using bit shifts instead of + * multiplication or division. Thus: + * + * AD << DDS + * SDF = --------- + * P + * + * or + * + * AD = (SDF >> DDS) x P + * + * where: + * + * DDS is the DLL Delay Shift, the logarithm to base 2 of the DDF. + */ + if (clock_period_in_ns > (nfc->max_dll_clock_period_in_ns >> 1)) { + dll_use_half_periods = true; + dll_delay_shift = 3 + 1; + } else { + dll_use_half_periods = false; + dll_delay_shift = 3; + } + + /* + * Compute the maximum sample delay the NFC allows, under current + * conditions. If the clock is running too slowly, no sample delay is + * possible. + */ + if (clock_period_in_ns > nfc->max_dll_clock_period_in_ns) + max_sample_delay_in_ns = 0; + else { + /* + * Compute the delay implied by the largest sample delay factor + * the NFC allows. + */ + max_sample_delay_in_ns = + (nfc->max_sample_delay_factor * clock_period_in_ns) >> + dll_delay_shift; + + /* + * Check if the implied sample delay larger than the NFC + * actually allows. + */ + if (max_sample_delay_in_ns > nfc->max_dll_delay_in_ns) + max_sample_delay_in_ns = nfc->max_dll_delay_in_ns; + } + + /* + * Check if improved timing information is available. If not, we have to + * use a less-sophisticated algorithm. + */ + if (!improved_timing_is_available) { + /* + * Fold the read setup time required by the NFC into the ideal + * sample delay. + */ + ideal_sample_delay_in_ns = target.gpmi_sample_delay_in_ns + + nfc->internal_data_setup_in_ns; + + /* + * The ideal sample delay may be greater than the maximum + * allowed by the NFC. If so, we can trade off sample delay time + * for more data setup time. + * + * In each iteration of the following loop, we add a cycle to + * the data setup time and subtract a corresponding amount from + * the sample delay until we've satisified the constraints or + * can't do any better. + */ + while ((ideal_sample_delay_in_ns > max_sample_delay_in_ns) && + (data_setup_in_cycles < nfc->max_data_setup_cycles)) { + + data_setup_in_cycles++; + ideal_sample_delay_in_ns -= clock_period_in_ns; + + if (ideal_sample_delay_in_ns < 0) + ideal_sample_delay_in_ns = 0; + + } + + /* + * Compute the sample delay factor that corresponds most closely + * to the ideal sample delay. If the result is too large for the + * NFC, use the maximum value. + * + * Notice that we use the ns_to_cycles function to compute the + * sample delay factor. We do this because the form of the + * computation is the same as that for calculating cycles. + */ + sample_delay_factor = + ns_to_cycles( + ideal_sample_delay_in_ns << dll_delay_shift, + clock_period_in_ns, 0); + + if (sample_delay_factor > nfc->max_sample_delay_factor) + sample_delay_factor = nfc->max_sample_delay_factor; + + /* Skip to the part where we return our results. */ + goto return_results; + } + + /* + * If control arrives here, we have more detailed timing information, + * so we can use a better algorithm. + */ + + /* + * Fold the read setup time required by the NFC into the maximum + * propagation delay. + */ + max_prop_delay_in_ns += nfc->internal_data_setup_in_ns; + + /* + * Earlier, we computed the number of clock cycles required to satisfy + * the data setup time. Now, we need to know the actual nanoseconds. + */ + data_setup_in_ns = clock_period_in_ns * data_setup_in_cycles; + + /* + * Compute tEYE, the width of the data eye when reading from the NAND + * Flash. The eye width is fundamentally determined by the data setup + * time, perturbed by propagation delays and some characteristics of the + * NAND Flash device. + * + * start of the eye = max_prop_delay + tREA + * end of the eye = min_prop_delay + tRHOH + data_setup + */ + tEYE = (int)min_prop_delay_in_ns + (int)target.tRHOH_in_ns + + (int)data_setup_in_ns; + + tEYE -= (int)max_prop_delay_in_ns + (int)target.tREA_in_ns; + + /* + * The eye must be open. If it's not, we can try to open it by + * increasing its main forcer, the data setup time. + * + * In each iteration of the following loop, we increase the data setup + * time by a single clock cycle. We do this until either the eye is + * open or we run into NFC limits. + */ + while ((tEYE <= 0) && + (data_setup_in_cycles < nfc->max_data_setup_cycles)) { + /* Give a cycle to data setup. */ + data_setup_in_cycles++; + /* Synchronize the data setup time with the cycles. */ + data_setup_in_ns += clock_period_in_ns; + /* Adjust tEYE accordingly. */ + tEYE += clock_period_in_ns; + } + + /* + * When control arrives here, the eye is open. The ideal time to sample + * the data is in the center of the eye: + * + * end of the eye + start of the eye + * --------------------------------- - data_setup + * 2 + * + * After some algebra, this simplifies to the code immediately below. + */ + ideal_sample_delay_in_ns = + ((int)max_prop_delay_in_ns + + (int)target.tREA_in_ns + + (int)min_prop_delay_in_ns + + (int)target.tRHOH_in_ns - + (int)data_setup_in_ns) >> 1; + + /* + * The following figure illustrates some aspects of a NAND Flash read: + * + * + * __ _____________________________________ + * RDN \_________________/ + * + * <---- tEYE -----> + * /-----------------\ + * Read Data ----------------------------< >--------- + * \-----------------/ + * ^ ^ ^ ^ + * | | | | + * |<--Data Setup -->|<--Delay Time -->| | + * | | | | + * | | | + * | |<-- Quantized Delay Time -->| + * | | | + * + * + * We have some issues we must now address: + * + * (1) The *ideal* sample delay time must not be negative. If it is, we + * jam it to zero. + * + * (2) The *ideal* sample delay time must not be greater than that + * allowed by the NFC. If it is, we can increase the data setup + * time, which will reduce the delay between the end of the data + * setup and the center of the eye. It will also make the eye + * larger, which might help with the next issue... + * + * (3) The *quantized* sample delay time must not fall either before the + * eye opens or after it closes (the latter is the problem + * illustrated in the above figure). + */ + + /* Jam a negative ideal sample delay to zero. */ + if (ideal_sample_delay_in_ns < 0) + ideal_sample_delay_in_ns = 0; + + /* + * Extend the data setup as needed to reduce the ideal sample delay + * below the maximum permitted by the NFC. + */ + while ((ideal_sample_delay_in_ns > max_sample_delay_in_ns) && + (data_setup_in_cycles < nfc->max_data_setup_cycles)) { + + /* Give a cycle to data setup. */ + data_setup_in_cycles++; + /* Synchronize the data setup time with the cycles. */ + data_setup_in_ns += clock_period_in_ns; + /* Adjust tEYE accordingly. */ + tEYE += clock_period_in_ns; + + /* + * Decrease the ideal sample delay by one half cycle, to keep it + * in the middle of the eye. + */ + ideal_sample_delay_in_ns -= (clock_period_in_ns >> 1); + + /* Jam a negative ideal sample delay to zero. */ + if (ideal_sample_delay_in_ns < 0) + ideal_sample_delay_in_ns = 0; + } + + /* + * Compute the sample delay factor that corresponds to the ideal sample + * delay. If the result is too large, then use the maximum allowed + * value. + * + * Notice that we use the ns_to_cycles function to compute the sample + * delay factor. We do this because the form of the computation is the + * same as that for calculating cycles. + */ + sample_delay_factor = + ns_to_cycles(ideal_sample_delay_in_ns << dll_delay_shift, + clock_period_in_ns, 0); + + if (sample_delay_factor > nfc->max_sample_delay_factor) + sample_delay_factor = nfc->max_sample_delay_factor; + + /* + * These macros conveniently encapsulate a computation we'll use to + * continuously evaluate whether or not the data sample delay is inside + * the eye. + */ + #define IDEAL_DELAY ((int) ideal_sample_delay_in_ns) + + #define QUANTIZED_DELAY \ + ((int) ((sample_delay_factor * clock_period_in_ns) >> \ + dll_delay_shift)) + + #define DELAY_ERROR (abs(QUANTIZED_DELAY - IDEAL_DELAY)) + + #define SAMPLE_IS_NOT_WITHIN_THE_EYE (DELAY_ERROR > (tEYE >> 1)) + + /* + * While the quantized sample time falls outside the eye, reduce the + * sample delay or extend the data setup to move the sampling point back + * toward the eye. Do not allow the number of data setup cycles to + * exceed the maximum allowed by the NFC. + */ + while (SAMPLE_IS_NOT_WITHIN_THE_EYE && + (data_setup_in_cycles < nfc->max_data_setup_cycles)) { + /* + * If control arrives here, the quantized sample delay falls + * outside the eye. Check if it's before the eye opens, or after + * the eye closes. + */ + if (QUANTIZED_DELAY > IDEAL_DELAY) { + /* + * If control arrives here, the quantized sample delay + * falls after the eye closes. Decrease the quantized + * delay time and then go back to re-evaluate. + */ + if (sample_delay_factor != 0) + sample_delay_factor--; + continue; + } + + /* + * If control arrives here, the quantized sample delay falls + * before the eye opens. Shift the sample point by increasing + * data setup time. This will also make the eye larger. + */ + + /* Give a cycle to data setup. */ + data_setup_in_cycles++; + /* Synchronize the data setup time with the cycles. */ + data_setup_in_ns += clock_period_in_ns; + /* Adjust tEYE accordingly. */ + tEYE += clock_period_in_ns; + + /* + * Decrease the ideal sample delay by one half cycle, to keep it + * in the middle of the eye. + */ + ideal_sample_delay_in_ns -= (clock_period_in_ns >> 1); + + /* ...and one less period for the delay time. */ + ideal_sample_delay_in_ns -= clock_period_in_ns; + + /* Jam a negative ideal sample delay to zero. */ + if (ideal_sample_delay_in_ns < 0) + ideal_sample_delay_in_ns = 0; + + /* + * We have a new ideal sample delay, so re-compute the quantized + * delay. + */ + sample_delay_factor = + ns_to_cycles( + ideal_sample_delay_in_ns << dll_delay_shift, + clock_period_in_ns, 0); + + if (sample_delay_factor > nfc->max_sample_delay_factor) + sample_delay_factor = nfc->max_sample_delay_factor; + } + + /* Control arrives here when we're ready to return our results. */ +return_results: + hw->data_setup_in_cycles = data_setup_in_cycles; + hw->data_hold_in_cycles = data_hold_in_cycles; + hw->address_setup_in_cycles = address_setup_in_cycles; + hw->use_half_periods = dll_use_half_periods; + hw->sample_delay_factor = sample_delay_factor; + hw->device_busy_timeout = GPMI_DEFAULT_BUSY_TIMEOUT; + hw->wrn_dly_sel = BV_GPMI_CTRL1_WRN_DLY_SEL_4_TO_8NS; + + /* Return success. */ + return 0; +} + +/* + * <1> Firstly, we should know what's the GPMI-clock means. + * The GPMI-clock is the internal clock in the gpmi nand controller. + * If you set 100MHz to gpmi nand controller, the GPMI-clock's period + * is 10ns. Mark the GPMI-clock's period as GPMI-clock-period. + * + * <2> Secondly, we should know what's the frequency on the nand chip pins. + * The frequency on the nand chip pins is derived from the GPMI-clock. + * We can get it from the following equation: + * + * F = G / (DS + DH) + * + * F : the frequency on the nand chip pins. + * G : the GPMI clock, such as 100MHz. + * DS : GPMI_HW_GPMI_TIMING0:DATA_SETUP + * DH : GPMI_HW_GPMI_TIMING0:DATA_HOLD + * + * <3> Thirdly, when the frequency on the nand chip pins is above 33MHz, + * the nand EDO(extended Data Out) timing could be applied. + * The GPMI implements a feedback read strobe to sample the read data. + * The feedback read strobe can be delayed to support the nand EDO timing + * where the read strobe may deasserts before the read data is valid, and + * read data is valid for some time after read strobe. + * + * The following figure illustrates some aspects of a NAND Flash read: + * + * |<---tREA---->| + * | | + * | | | + * |<--tRP-->| | + * | | | + * __ ___|__________________________________ + * RDN \________/ | + * | + * /---------\ + * Read Data --------------< >--------- + * \---------/ + * | | + * |<-D->| + * FeedbackRDN ________ ____________ + * \___________/ + * + * D stands for delay, set in the HW_GPMI_CTRL1:RDN_DELAY. + * + * + * <4> Now, we begin to describe how to compute the right RDN_DELAY. + * + * 4.1) From the aspect of the nand chip pins: + * Delay = (tREA + C - tRP) {1} + * + * tREA : the maximum read access time. From the ONFI nand standards, + * we know that tREA is 16ns in mode 5, tREA is 20ns is mode 4. + * Please check it in : www.onfi.org + * C : a constant for adjust the delay. default is 4. + * tRP : the read pulse width. + * Specified by the HW_GPMI_TIMING0:DATA_SETUP: + * tRP = (GPMI-clock-period) * DATA_SETUP + * + * 4.2) From the aspect of the GPMI nand controller: + * Delay = RDN_DELAY * 0.125 * RP {2} + * + * RP : the DLL reference period. + * if (GPMI-clock-period > DLL_THRETHOLD) + * RP = GPMI-clock-period / 2; + * else + * RP = GPMI-clock-period; + * + * Set the HW_GPMI_CTRL1:HALF_PERIOD if GPMI-clock-period + * is greater DLL_THRETHOLD. In other SOCs, the DLL_THRETHOLD + * is 16ns, but in mx6q, we use 12ns. + * + * 4.3) since {1} equals {2}, we get: + * + * (tREA + 4 - tRP) * 8 + * RDN_DELAY = --------------------- {3} + * RP + * + * 4.4) We only support the fastest asynchronous mode of ONFI nand. + * For some ONFI nand, the mode 4 is the fastest mode; + * while for some ONFI nand, the mode 5 is the fastest mode. + * So we only support the mode 4 and mode 5. It is no need to + * support other modes. + */ +static void gpmi_compute_edo_timing(struct gpmi_nand_data *this, + struct gpmi_nfc_hardware_timing *hw) +{ + struct resources *r = &this->resources; + unsigned long rate = clk_get_rate(r->clock[0]); + int mode = this->timing_mode; + int dll_threshold = this->devdata->max_chain_delay; + unsigned long delay; + unsigned long clk_period; + int t_rea; + int c = 4; + int t_rp; + int rp; + + /* + * [1] for GPMI_HW_GPMI_TIMING0: + * The async mode requires 40MHz for mode 4, 50MHz for mode 5. + * The GPMI can support 100MHz at most. So if we want to + * get the 40MHz or 50MHz, we have to set DS=1, DH=1. + * Set the ADDRESS_SETUP to 0 in mode 4. + */ + hw->data_setup_in_cycles = 1; + hw->data_hold_in_cycles = 1; + hw->address_setup_in_cycles = ((mode == 5) ? 1 : 0); + + /* [2] for GPMI_HW_GPMI_TIMING1 */ + hw->device_busy_timeout = 0x9000; + + /* [3] for GPMI_HW_GPMI_CTRL1 */ + hw->wrn_dly_sel = BV_GPMI_CTRL1_WRN_DLY_SEL_NO_DELAY; + + /* + * Enlarge 10 times for the numerator and denominator in {3}. + * This make us to get more accurate result. + */ + clk_period = NSEC_PER_SEC / (rate / 10); + dll_threshold *= 10; + t_rea = ((mode == 5) ? 16 : 20) * 10; + c *= 10; + + t_rp = clk_period * 1; /* DATA_SETUP is 1 */ + + if (clk_period > dll_threshold) { + hw->use_half_periods = 1; + rp = clk_period / 2; + } else { + hw->use_half_periods = 0; + rp = clk_period; + } + + /* + * Multiply the numerator with 10, we could do a round off: + * 7.8 round up to 8; 7.4 round down to 7. + */ + delay = (((t_rea + c - t_rp) * 8) * 10) / rp; + delay = (delay + 5) / 10; + + hw->sample_delay_factor = delay; +} + +static int enable_edo_mode(struct gpmi_nand_data *this, int mode) +{ + struct resources *r = &this->resources; + struct nand_chip *nand = &this->nand; + struct mtd_info *mtd = nand_to_mtd(nand); + uint8_t *feature; + unsigned long rate; + int ret; + + feature = kzalloc(ONFI_SUBFEATURE_PARAM_LEN, GFP_KERNEL); + if (!feature) + return -ENOMEM; + + nand->select_chip(mtd, 0); + + /* [1] send SET FEATURE command to NAND */ + feature[0] = mode; + ret = nand->onfi_set_features(mtd, nand, + ONFI_FEATURE_ADDR_TIMING_MODE, feature); + if (ret) + goto err_out; + + /* [2] send GET FEATURE command to double-check the timing mode */ + memset(feature, 0, ONFI_SUBFEATURE_PARAM_LEN); + ret = nand->onfi_get_features(mtd, nand, + ONFI_FEATURE_ADDR_TIMING_MODE, feature); + if (ret || feature[0] != mode) + goto err_out; + + nand->select_chip(mtd, -1); + + /* [3] set the main IO clock, 100MHz for mode 5, 80MHz for mode 4. */ + rate = (mode == 5) ? 100000000 : 80000000; + clk_set_rate(r->clock[0], rate); + + /* Let the gpmi_begin() re-compute the timing again. */ + this->flags &= ~GPMI_TIMING_INIT_OK; + + this->flags |= GPMI_ASYNC_EDO_ENABLED; + this->timing_mode = mode; + kfree(feature); + dev_info(this->dev, "enable the asynchronous EDO mode %d\n", mode); + return 0; + +err_out: + nand->select_chip(mtd, -1); + kfree(feature); + dev_err(this->dev, "mode:%d ,failed in set feature.\n", mode); + return -EINVAL; +} + +int gpmi_extra_init(struct gpmi_nand_data *this) +{ + struct nand_chip *chip = &this->nand; + + /* Enable the asynchronous EDO feature. */ + if (GPMI_IS_MX6(this) && chip->onfi_version) { + int mode = onfi_get_async_timing_mode(chip); + + /* We only support the timing mode 4 and mode 5. */ + if (mode & ONFI_TIMING_MODE_5) + mode = 5; + else if (mode & ONFI_TIMING_MODE_4) + mode = 4; + else + return 0; + + return enable_edo_mode(this, mode); + } + return 0; +} + +/* Begin the I/O */ +void gpmi_begin(struct gpmi_nand_data *this) +{ + struct resources *r = &this->resources; + void __iomem *gpmi_regs = r->gpmi_regs; + unsigned int clock_period_in_ns; + uint32_t reg; + unsigned int dll_wait_time_in_us; + struct gpmi_nfc_hardware_timing hw; + int ret; + + /* Enable the clock. */ + ret = gpmi_enable_clk(this); + if (ret) { + dev_err(this->dev, "We failed in enable the clk\n"); + goto err_out; + } + + /* Only initialize the timing once */ + if (this->flags & GPMI_TIMING_INIT_OK) + return; + this->flags |= GPMI_TIMING_INIT_OK; + + if (this->flags & GPMI_ASYNC_EDO_ENABLED) + gpmi_compute_edo_timing(this, &hw); + else + gpmi_nfc_compute_hardware_timing(this, &hw); + + /* [1] Set HW_GPMI_TIMING0 */ + reg = BF_GPMI_TIMING0_ADDRESS_SETUP(hw.address_setup_in_cycles) | + BF_GPMI_TIMING0_DATA_HOLD(hw.data_hold_in_cycles) | + BF_GPMI_TIMING0_DATA_SETUP(hw.data_setup_in_cycles); + + writel(reg, gpmi_regs + HW_GPMI_TIMING0); + + /* [2] Set HW_GPMI_TIMING1 */ + writel(BF_GPMI_TIMING1_BUSY_TIMEOUT(hw.device_busy_timeout), + gpmi_regs + HW_GPMI_TIMING1); + + /* [3] The following code is to set the HW_GPMI_CTRL1. */ + + /* Set the WRN_DLY_SEL */ + writel(BM_GPMI_CTRL1_WRN_DLY_SEL, gpmi_regs + HW_GPMI_CTRL1_CLR); + writel(BF_GPMI_CTRL1_WRN_DLY_SEL(hw.wrn_dly_sel), + gpmi_regs + HW_GPMI_CTRL1_SET); + + /* DLL_ENABLE must be set to 0 when setting RDN_DELAY or HALF_PERIOD. */ + writel(BM_GPMI_CTRL1_DLL_ENABLE, gpmi_regs + HW_GPMI_CTRL1_CLR); + + /* Clear out the DLL control fields. */ + reg = BM_GPMI_CTRL1_RDN_DELAY | BM_GPMI_CTRL1_HALF_PERIOD; + writel(reg, gpmi_regs + HW_GPMI_CTRL1_CLR); + + /* If no sample delay is called for, return immediately. */ + if (!hw.sample_delay_factor) + return; + + /* Set RDN_DELAY or HALF_PERIOD. */ + reg = ((hw.use_half_periods) ? BM_GPMI_CTRL1_HALF_PERIOD : 0) + | BF_GPMI_CTRL1_RDN_DELAY(hw.sample_delay_factor); + + writel(reg, gpmi_regs + HW_GPMI_CTRL1_SET); + + /* At last, we enable the DLL. */ + writel(BM_GPMI_CTRL1_DLL_ENABLE, gpmi_regs + HW_GPMI_CTRL1_SET); + + /* + * After we enable the GPMI DLL, we have to wait 64 clock cycles before + * we can use the GPMI. Calculate the amount of time we need to wait, + * in microseconds. + */ + clock_period_in_ns = NSEC_PER_SEC / clk_get_rate(r->clock[0]); + dll_wait_time_in_us = (clock_period_in_ns * 64) / 1000; + + if (!dll_wait_time_in_us) + dll_wait_time_in_us = 1; + + /* Wait for the DLL to settle. */ + udelay(dll_wait_time_in_us); + +err_out: + return; +} + +void gpmi_end(struct gpmi_nand_data *this) +{ + gpmi_disable_clk(this); +} + +/* Clears a BCH interrupt. */ +void gpmi_clear_bch(struct gpmi_nand_data *this) +{ + struct resources *r = &this->resources; + writel(BM_BCH_CTRL_COMPLETE_IRQ, r->bch_regs + HW_BCH_CTRL_CLR); +} + +/* Returns the Ready/Busy status of the given chip. */ +int gpmi_is_ready(struct gpmi_nand_data *this, unsigned chip) +{ + struct resources *r = &this->resources; + uint32_t mask = 0; + uint32_t reg = 0; + + if (GPMI_IS_MX23(this)) { + mask = MX23_BM_GPMI_DEBUG_READY0 << chip; + reg = readl(r->gpmi_regs + HW_GPMI_DEBUG); + } else if (GPMI_IS_MX28(this) || GPMI_IS_MX6(this)) { + /* + * In the imx6, all the ready/busy pins are bound + * together. So we only need to check chip 0. + */ + if (GPMI_IS_MX6(this)) + chip = 0; + + /* MX28 shares the same R/B register as MX6Q. */ + mask = MX28_BF_GPMI_STAT_READY_BUSY(1 << chip); + reg = readl(r->gpmi_regs + HW_GPMI_STAT); + } else + dev_err(this->dev, "unknown arch.\n"); + return reg & mask; +} + +static inline void set_dma_type(struct gpmi_nand_data *this, + enum dma_ops_type type) +{ + this->last_dma_type = this->dma_type; + this->dma_type = type; +} + +int gpmi_send_command(struct gpmi_nand_data *this) +{ + struct dma_chan *channel = get_dma_chan(this); + struct dma_async_tx_descriptor *desc; + struct scatterlist *sgl; + int chip = this->current_chip; + u32 pio[3]; + + /* [1] send out the PIO words */ + pio[0] = BF_GPMI_CTRL0_COMMAND_MODE(BV_GPMI_CTRL0_COMMAND_MODE__WRITE) + | BM_GPMI_CTRL0_WORD_LENGTH + | BF_GPMI_CTRL0_CS(chip, this) + | BF_GPMI_CTRL0_LOCK_CS(LOCK_CS_ENABLE, this) + | BF_GPMI_CTRL0_ADDRESS(BV_GPMI_CTRL0_ADDRESS__NAND_CLE) + | BM_GPMI_CTRL0_ADDRESS_INCREMENT + | BF_GPMI_CTRL0_XFER_COUNT(this->command_length); + pio[1] = pio[2] = 0; + desc = dmaengine_prep_slave_sg(channel, + (struct scatterlist *)pio, + ARRAY_SIZE(pio), DMA_TRANS_NONE, 0); + if (!desc) + return -EINVAL; + + /* [2] send out the COMMAND + ADDRESS string stored in @buffer */ + sgl = &this->cmd_sgl; + + sg_init_one(sgl, this->cmd_buffer, this->command_length); + dma_map_sg(this->dev, sgl, 1, DMA_TO_DEVICE); + desc = dmaengine_prep_slave_sg(channel, + sgl, 1, DMA_MEM_TO_DEV, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!desc) + return -EINVAL; + + /* [3] submit the DMA */ + set_dma_type(this, DMA_FOR_COMMAND); + return start_dma_without_bch_irq(this, desc); +} + +int gpmi_send_data(struct gpmi_nand_data *this) +{ + struct dma_async_tx_descriptor *desc; + struct dma_chan *channel = get_dma_chan(this); + int chip = this->current_chip; + uint32_t command_mode; + uint32_t address; + u32 pio[2]; + + /* [1] PIO */ + command_mode = BV_GPMI_CTRL0_COMMAND_MODE__WRITE; + address = BV_GPMI_CTRL0_ADDRESS__NAND_DATA; + + pio[0] = BF_GPMI_CTRL0_COMMAND_MODE(command_mode) + | BM_GPMI_CTRL0_WORD_LENGTH + | BF_GPMI_CTRL0_CS(chip, this) + | BF_GPMI_CTRL0_LOCK_CS(LOCK_CS_ENABLE, this) + | BF_GPMI_CTRL0_ADDRESS(address) + | BF_GPMI_CTRL0_XFER_COUNT(this->upper_len); + pio[1] = 0; + desc = dmaengine_prep_slave_sg(channel, (struct scatterlist *)pio, + ARRAY_SIZE(pio), DMA_TRANS_NONE, 0); + if (!desc) + return -EINVAL; + + /* [2] send DMA request */ + prepare_data_dma(this, DMA_TO_DEVICE); + desc = dmaengine_prep_slave_sg(channel, &this->data_sgl, + 1, DMA_MEM_TO_DEV, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!desc) + return -EINVAL; + + /* [3] submit the DMA */ + set_dma_type(this, DMA_FOR_WRITE_DATA); + return start_dma_without_bch_irq(this, desc); +} + +int gpmi_read_data(struct gpmi_nand_data *this) +{ + struct dma_async_tx_descriptor *desc; + struct dma_chan *channel = get_dma_chan(this); + int chip = this->current_chip; + u32 pio[2]; + + /* [1] : send PIO */ + pio[0] = BF_GPMI_CTRL0_COMMAND_MODE(BV_GPMI_CTRL0_COMMAND_MODE__READ) + | BM_GPMI_CTRL0_WORD_LENGTH + | BF_GPMI_CTRL0_CS(chip, this) + | BF_GPMI_CTRL0_LOCK_CS(LOCK_CS_ENABLE, this) + | BF_GPMI_CTRL0_ADDRESS(BV_GPMI_CTRL0_ADDRESS__NAND_DATA) + | BF_GPMI_CTRL0_XFER_COUNT(this->upper_len); + pio[1] = 0; + desc = dmaengine_prep_slave_sg(channel, + (struct scatterlist *)pio, + ARRAY_SIZE(pio), DMA_TRANS_NONE, 0); + if (!desc) + return -EINVAL; + + /* [2] : send DMA request */ + prepare_data_dma(this, DMA_FROM_DEVICE); + desc = dmaengine_prep_slave_sg(channel, &this->data_sgl, + 1, DMA_DEV_TO_MEM, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!desc) + return -EINVAL; + + /* [3] : submit the DMA */ + set_dma_type(this, DMA_FOR_READ_DATA); + return start_dma_without_bch_irq(this, desc); +} + +int gpmi_send_page(struct gpmi_nand_data *this, + dma_addr_t payload, dma_addr_t auxiliary) +{ + struct bch_geometry *geo = &this->bch_geometry; + uint32_t command_mode; + uint32_t address; + uint32_t ecc_command; + uint32_t buffer_mask; + struct dma_async_tx_descriptor *desc; + struct dma_chan *channel = get_dma_chan(this); + int chip = this->current_chip; + u32 pio[6]; + + /* A DMA descriptor that does an ECC page read. */ + command_mode = BV_GPMI_CTRL0_COMMAND_MODE__WRITE; + address = BV_GPMI_CTRL0_ADDRESS__NAND_DATA; + ecc_command = BV_GPMI_ECCCTRL_ECC_CMD__BCH_ENCODE; + buffer_mask = BV_GPMI_ECCCTRL_BUFFER_MASK__BCH_PAGE | + BV_GPMI_ECCCTRL_BUFFER_MASK__BCH_AUXONLY; + + pio[0] = BF_GPMI_CTRL0_COMMAND_MODE(command_mode) + | BM_GPMI_CTRL0_WORD_LENGTH + | BF_GPMI_CTRL0_CS(chip, this) + | BF_GPMI_CTRL0_LOCK_CS(LOCK_CS_ENABLE, this) + | BF_GPMI_CTRL0_ADDRESS(address) + | BF_GPMI_CTRL0_XFER_COUNT(0); + pio[1] = 0; + pio[2] = BM_GPMI_ECCCTRL_ENABLE_ECC + | BF_GPMI_ECCCTRL_ECC_CMD(ecc_command) + | BF_GPMI_ECCCTRL_BUFFER_MASK(buffer_mask); + pio[3] = geo->page_size; + pio[4] = payload; + pio[5] = auxiliary; + + desc = dmaengine_prep_slave_sg(channel, + (struct scatterlist *)pio, + ARRAY_SIZE(pio), DMA_TRANS_NONE, + DMA_CTRL_ACK); + if (!desc) + return -EINVAL; + + set_dma_type(this, DMA_FOR_WRITE_ECC_PAGE); + return start_dma_with_bch_irq(this, desc); +} + +int gpmi_read_page(struct gpmi_nand_data *this, + dma_addr_t payload, dma_addr_t auxiliary) +{ + struct bch_geometry *geo = &this->bch_geometry; + uint32_t command_mode; + uint32_t address; + uint32_t ecc_command; + uint32_t buffer_mask; + struct dma_async_tx_descriptor *desc; + struct dma_chan *channel = get_dma_chan(this); + int chip = this->current_chip; + u32 pio[6]; + + /* [1] Wait for the chip to report ready. */ + command_mode = BV_GPMI_CTRL0_COMMAND_MODE__WAIT_FOR_READY; + address = BV_GPMI_CTRL0_ADDRESS__NAND_DATA; + + pio[0] = BF_GPMI_CTRL0_COMMAND_MODE(command_mode) + | BM_GPMI_CTRL0_WORD_LENGTH + | BF_GPMI_CTRL0_CS(chip, this) + | BF_GPMI_CTRL0_LOCK_CS(LOCK_CS_ENABLE, this) + | BF_GPMI_CTRL0_ADDRESS(address) + | BF_GPMI_CTRL0_XFER_COUNT(0); + pio[1] = 0; + desc = dmaengine_prep_slave_sg(channel, + (struct scatterlist *)pio, 2, + DMA_TRANS_NONE, 0); + if (!desc) + return -EINVAL; + + /* [2] Enable the BCH block and read. */ + command_mode = BV_GPMI_CTRL0_COMMAND_MODE__READ; + address = BV_GPMI_CTRL0_ADDRESS__NAND_DATA; + ecc_command = BV_GPMI_ECCCTRL_ECC_CMD__BCH_DECODE; + buffer_mask = BV_GPMI_ECCCTRL_BUFFER_MASK__BCH_PAGE + | BV_GPMI_ECCCTRL_BUFFER_MASK__BCH_AUXONLY; + + pio[0] = BF_GPMI_CTRL0_COMMAND_MODE(command_mode) + | BM_GPMI_CTRL0_WORD_LENGTH + | BF_GPMI_CTRL0_CS(chip, this) + | BF_GPMI_CTRL0_LOCK_CS(LOCK_CS_ENABLE, this) + | BF_GPMI_CTRL0_ADDRESS(address) + | BF_GPMI_CTRL0_XFER_COUNT(geo->page_size); + + pio[1] = 0; + pio[2] = BM_GPMI_ECCCTRL_ENABLE_ECC + | BF_GPMI_ECCCTRL_ECC_CMD(ecc_command) + | BF_GPMI_ECCCTRL_BUFFER_MASK(buffer_mask); + pio[3] = geo->page_size; + pio[4] = payload; + pio[5] = auxiliary; + desc = dmaengine_prep_slave_sg(channel, + (struct scatterlist *)pio, + ARRAY_SIZE(pio), DMA_TRANS_NONE, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!desc) + return -EINVAL; + + /* [3] Disable the BCH block */ + command_mode = BV_GPMI_CTRL0_COMMAND_MODE__WAIT_FOR_READY; + address = BV_GPMI_CTRL0_ADDRESS__NAND_DATA; + + pio[0] = BF_GPMI_CTRL0_COMMAND_MODE(command_mode) + | BM_GPMI_CTRL0_WORD_LENGTH + | BF_GPMI_CTRL0_CS(chip, this) + | BF_GPMI_CTRL0_LOCK_CS(LOCK_CS_ENABLE, this) + | BF_GPMI_CTRL0_ADDRESS(address) + | BF_GPMI_CTRL0_XFER_COUNT(geo->page_size); + pio[1] = 0; + pio[2] = 0; /* clear GPMI_HW_GPMI_ECCCTRL, disable the BCH. */ + desc = dmaengine_prep_slave_sg(channel, + (struct scatterlist *)pio, 3, + DMA_TRANS_NONE, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!desc) + return -EINVAL; + + /* [4] submit the DMA */ + set_dma_type(this, DMA_FOR_READ_ECC_PAGE); + return start_dma_with_bch_irq(this, desc); +} + +/** + * gpmi_copy_bits - copy bits from one memory region to another + * @dst: destination buffer + * @dst_bit_off: bit offset we're starting to write at + * @src: source buffer + * @src_bit_off: bit offset we're starting to read from + * @nbits: number of bits to copy + * + * This functions copies bits from one memory region to another, and is used by + * the GPMI driver to copy ECC sections which are not guaranteed to be byte + * aligned. + * + * src and dst should not overlap. + * + */ +void gpmi_copy_bits(u8 *dst, size_t dst_bit_off, + const u8 *src, size_t src_bit_off, + size_t nbits) +{ + size_t i; + size_t nbytes; + u32 src_buffer = 0; + size_t bits_in_src_buffer = 0; + + if (!nbits) + return; + + /* + * Move src and dst pointers to the closest byte pointer and store bit + * offsets within a byte. + */ + src += src_bit_off / 8; + src_bit_off %= 8; + + dst += dst_bit_off / 8; + dst_bit_off %= 8; + + /* + * Initialize the src_buffer value with bits available in the first + * byte of data so that we end up with a byte aligned src pointer. + */ + if (src_bit_off) { + src_buffer = src[0] >> src_bit_off; + if (nbits >= (8 - src_bit_off)) { + bits_in_src_buffer += 8 - src_bit_off; + } else { + src_buffer &= GENMASK(nbits - 1, 0); + bits_in_src_buffer += nbits; + } + nbits -= bits_in_src_buffer; + src++; + } + + /* Calculate the number of bytes that can be copied from src to dst. */ + nbytes = nbits / 8; + + /* Try to align dst to a byte boundary. */ + if (dst_bit_off) { + if (bits_in_src_buffer < (8 - dst_bit_off) && nbytes) { + src_buffer |= src[0] << bits_in_src_buffer; + bits_in_src_buffer += 8; + src++; + nbytes--; + } + + if (bits_in_src_buffer >= (8 - dst_bit_off)) { + dst[0] &= GENMASK(dst_bit_off - 1, 0); + dst[0] |= src_buffer << dst_bit_off; + src_buffer >>= (8 - dst_bit_off); + bits_in_src_buffer -= (8 - dst_bit_off); + dst_bit_off = 0; + dst++; + if (bits_in_src_buffer > 7) { + bits_in_src_buffer -= 8; + dst[0] = src_buffer; + dst++; + src_buffer >>= 8; + } + } + } + + if (!bits_in_src_buffer && !dst_bit_off) { + /* + * Both src and dst pointers are byte aligned, thus we can + * just use the optimized memcpy function. + */ + if (nbytes) + memcpy(dst, src, nbytes); + } else { + /* + * src buffer is not byte aligned, hence we have to copy each + * src byte to the src_buffer variable before extracting a byte + * to store in dst. + */ + for (i = 0; i < nbytes; i++) { + src_buffer |= src[i] << bits_in_src_buffer; + dst[i] = src_buffer; + src_buffer >>= 8; + } + } + /* Update dst and src pointers */ + dst += nbytes; + src += nbytes; + + /* + * nbits is the number of remaining bits. It should not exceed 8 as + * we've already copied as much bytes as possible. + */ + nbits %= 8; + + /* + * If there's no more bits to copy to the destination and src buffer + * was already byte aligned, then we're done. + */ + if (!nbits && !bits_in_src_buffer) + return; + + /* Copy the remaining bits to src_buffer */ + if (nbits) + src_buffer |= (*src & GENMASK(nbits - 1, 0)) << + bits_in_src_buffer; + bits_in_src_buffer += nbits; + + /* + * In case there were not enough bits to get a byte aligned dst buffer + * prepare the src_buffer variable to match the dst organization (shift + * src_buffer by dst_bit_off and retrieve the least significant bits + * from dst). + */ + if (dst_bit_off) + src_buffer = (src_buffer << dst_bit_off) | + (*dst & GENMASK(dst_bit_off - 1, 0)); + bits_in_src_buffer += dst_bit_off; + + /* + * Keep most significant bits from dst if we end up with an unaligned + * number of bits. + */ + nbytes = bits_in_src_buffer / 8; + if (bits_in_src_buffer % 8) { + src_buffer |= (dst[nbytes] & + GENMASK(7, bits_in_src_buffer % 8)) << + (nbytes * 8); + nbytes++; + } + + /* Copy the remaining bytes to dst */ + for (i = 0; i < nbytes; i++) { + dst[i] = src_buffer; + src_buffer >>= 8; + } +} |
