diff options
Diffstat (limited to 'drivers/tty/serial/amba-pl011.c')
| -rw-r--r-- | drivers/tty/serial/amba-pl011.c | 1519 |
1 files changed, 1519 insertions, 0 deletions
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c new file mode 100644 index 0000000..e76d7d0 --- /dev/null +++ b/drivers/tty/serial/amba-pl011.c @@ -0,0 +1,1519 @@ +/* + * linux/drivers/char/amba.c + * + * Driver for AMBA serial ports + * + * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o. + * + * Copyright 1999 ARM Limited + * Copyright (C) 2000 Deep Blue Solutions Ltd. + * Copyright (C) 2010 ST-Ericsson SA + * + * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + * This is a generic driver for ARM AMBA-type serial ports. They + * have a lot of 16550-like features, but are not register compatible. + * Note that although they do have CTS, DCD and DSR inputs, they do + * not have an RI input, nor do they have DTR or RTS outputs. If + * required, these have to be supplied via some other means (eg, GPIO) + * and hooked into this driver. + */ + +#if defined(CONFIG_SERIAL_AMBA_PL011_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) +#define SUPPORT_SYSRQ +#endif + +#include <linux/module.h> +#include <linux/ioport.h> +#include <linux/init.h> +#include <linux/console.h> +#include <linux/sysrq.h> +#include <linux/device.h> +#include <linux/tty.h> +#include <linux/tty_flip.h> +#include <linux/serial_core.h> +#include <linux/serial.h> +#include <linux/amba/bus.h> +#include <linux/amba/serial.h> +#include <linux/clk.h> +#include <linux/slab.h> +#include <linux/dmaengine.h> +#include <linux/dma-mapping.h> +#include <linux/scatterlist.h> + +#include <asm/io.h> +#include <asm/sizes.h> + +#define UART_NR 14 + +#define SERIAL_AMBA_MAJOR 204 +#define SERIAL_AMBA_MINOR 64 +#define SERIAL_AMBA_NR UART_NR + +#define AMBA_ISR_PASS_LIMIT 256 + +#define UART_DR_ERROR (UART011_DR_OE|UART011_DR_BE|UART011_DR_PE|UART011_DR_FE) +#define UART_DUMMY_DR_RX (1 << 16) + +/* There is by now at least one vendor with differing details, so handle it */ +struct vendor_data { + unsigned int ifls; + unsigned int fifosize; + unsigned int lcrh_tx; + unsigned int lcrh_rx; + bool oversampling; + bool dma_threshold; +}; + +static struct vendor_data vendor_arm = { + .ifls = UART011_IFLS_RX4_8|UART011_IFLS_TX4_8, + .fifosize = 16, + .lcrh_tx = UART011_LCRH, + .lcrh_rx = UART011_LCRH, + .oversampling = false, + .dma_threshold = false, +}; + +static struct vendor_data vendor_st = { + .ifls = UART011_IFLS_RX_HALF|UART011_IFLS_TX_HALF, + .fifosize = 64, + .lcrh_tx = ST_UART011_LCRH_TX, + .lcrh_rx = ST_UART011_LCRH_RX, + .oversampling = true, + .dma_threshold = true, +}; + +/* Deals with DMA transactions */ +struct pl011_dmatx_data { + struct dma_chan *chan; + struct scatterlist sg; + char *buf; + bool queued; +}; + +/* + * We wrap our port structure around the generic uart_port. + */ +struct uart_amba_port { + struct uart_port port; + struct clk *clk; + const struct vendor_data *vendor; + unsigned int dmacr; /* dma control reg */ + unsigned int im; /* interrupt mask */ + unsigned int old_status; + unsigned int fifosize; /* vendor-specific */ + unsigned int lcrh_tx; /* vendor-specific */ + unsigned int lcrh_rx; /* vendor-specific */ + bool autorts; + char type[12]; +#ifdef CONFIG_DMA_ENGINE + /* DMA stuff */ + bool using_dma; + struct pl011_dmatx_data dmatx; +#endif +}; + +/* + * All the DMA operation mode stuff goes inside this ifdef. + * This assumes that you have a generic DMA device interface, + * no custom DMA interfaces are supported. + */ +#ifdef CONFIG_DMA_ENGINE + +#define PL011_DMA_BUFFER_SIZE PAGE_SIZE + +static void pl011_dma_probe_initcall(struct uart_amba_port *uap) +{ + /* DMA is the sole user of the platform data right now */ + struct amba_pl011_data *plat = uap->port.dev->platform_data; + struct dma_slave_config tx_conf = { + .dst_addr = uap->port.mapbase + UART01x_DR, + .dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE, + .direction = DMA_TO_DEVICE, + .dst_maxburst = uap->fifosize >> 1, + }; + struct dma_chan *chan; + dma_cap_mask_t mask; + + /* We need platform data */ + if (!plat || !plat->dma_filter) { + dev_info(uap->port.dev, "no DMA platform data\n"); + return; + } + + /* Try to acquire a generic DMA engine slave channel */ + dma_cap_zero(mask); + dma_cap_set(DMA_SLAVE, mask); + + chan = dma_request_channel(mask, plat->dma_filter, plat->dma_tx_param); + if (!chan) { + dev_err(uap->port.dev, "no TX DMA channel!\n"); + return; + } + + dmaengine_slave_config(chan, &tx_conf); + uap->dmatx.chan = chan; + + dev_info(uap->port.dev, "DMA channel TX %s\n", + dma_chan_name(uap->dmatx.chan)); +} + +#ifndef MODULE +/* + * Stack up the UARTs and let the above initcall be done at device + * initcall time, because the serial driver is called as an arch + * initcall, and at this time the DMA subsystem is not yet registered. + * At this point the driver will switch over to using DMA where desired. + */ +struct dma_uap { + struct list_head node; + struct uart_amba_port *uap; +}; + +static LIST_HEAD(pl011_dma_uarts); + +static int __init pl011_dma_initcall(void) +{ + struct list_head *node, *tmp; + + list_for_each_safe(node, tmp, &pl011_dma_uarts) { + struct dma_uap *dmau = list_entry(node, struct dma_uap, node); + pl011_dma_probe_initcall(dmau->uap); + list_del(node); + kfree(dmau); + } + return 0; +} + +device_initcall(pl011_dma_initcall); + +static void pl011_dma_probe(struct uart_amba_port *uap) +{ + struct dma_uap *dmau = kzalloc(sizeof(struct dma_uap), GFP_KERNEL); + if (dmau) { + dmau->uap = uap; + list_add_tail(&dmau->node, &pl011_dma_uarts); + } +} +#else +static void pl011_dma_probe(struct uart_amba_port *uap) +{ + pl011_dma_probe_initcall(uap); +} +#endif + +static void pl011_dma_remove(struct uart_amba_port *uap) +{ + /* TODO: remove the initcall if it has not yet executed */ + if (uap->dmatx.chan) + dma_release_channel(uap->dmatx.chan); +} + + +/* Forward declare this for the refill routine */ +static int pl011_dma_tx_refill(struct uart_amba_port *uap); + +/* + * The current DMA TX buffer has been sent. + * Try to queue up another DMA buffer. + */ +static void pl011_dma_tx_callback(void *data) +{ + struct uart_amba_port *uap = data; + struct pl011_dmatx_data *dmatx = &uap->dmatx; + unsigned long flags; + u16 dmacr; + + spin_lock_irqsave(&uap->port.lock, flags); + if (uap->dmatx.queued) + dma_unmap_sg(dmatx->chan->device->dev, &dmatx->sg, 1, + DMA_TO_DEVICE); + + dmacr = uap->dmacr; + uap->dmacr = dmacr & ~UART011_TXDMAE; + writew(uap->dmacr, uap->port.membase + UART011_DMACR); + + /* + * If TX DMA was disabled, it means that we've stopped the DMA for + * some reason (eg, XOFF received, or we want to send an X-char.) + * + * Note: we need to be careful here of a potential race between DMA + * and the rest of the driver - if the driver disables TX DMA while + * a TX buffer completing, we must update the tx queued status to + * get further refills (hence we check dmacr). + */ + if (!(dmacr & UART011_TXDMAE) || uart_tx_stopped(&uap->port) || + uart_circ_empty(&uap->port.state->xmit)) { + uap->dmatx.queued = false; + spin_unlock_irqrestore(&uap->port.lock, flags); + return; + } + + if (pl011_dma_tx_refill(uap) <= 0) { + /* + * We didn't queue a DMA buffer for some reason, but we + * have data pending to be sent. Re-enable the TX IRQ. + */ + uap->im |= UART011_TXIM; + writew(uap->im, uap->port.membase + UART011_IMSC); + } + spin_unlock_irqrestore(&uap->port.lock, flags); +} + +/* + * Try to refill the TX DMA buffer. + * Locking: called with port lock held and IRQs disabled. + * Returns: + * 1 if we queued up a TX DMA buffer. + * 0 if we didn't want to handle this by DMA + * <0 on error + */ +static int pl011_dma_tx_refill(struct uart_amba_port *uap) +{ + struct pl011_dmatx_data *dmatx = &uap->dmatx; + struct dma_chan *chan = dmatx->chan; + struct dma_device *dma_dev = chan->device; + struct dma_async_tx_descriptor *desc; + struct circ_buf *xmit = &uap->port.state->xmit; + unsigned int count; + + /* + * Try to avoid the overhead involved in using DMA if the + * transaction fits in the first half of the FIFO, by using + * the standard interrupt handling. This ensures that we + * issue a uart_write_wakeup() at the appropriate time. + */ + count = uart_circ_chars_pending(xmit); + if (count < (uap->fifosize >> 1)) { + uap->dmatx.queued = false; + return 0; + } + + /* + * Bodge: don't send the last character by DMA, as this + * will prevent XON from notifying us to restart DMA. + */ + count -= 1; + + /* Else proceed to copy the TX chars to the DMA buffer and fire DMA */ + if (count > PL011_DMA_BUFFER_SIZE) + count = PL011_DMA_BUFFER_SIZE; + + if (xmit->tail < xmit->head) + memcpy(&dmatx->buf[0], &xmit->buf[xmit->tail], count); + else { + size_t first = UART_XMIT_SIZE - xmit->tail; + size_t second = xmit->head; + + memcpy(&dmatx->buf[0], &xmit->buf[xmit->tail], first); + if (second) + memcpy(&dmatx->buf[first], &xmit->buf[0], second); + } + + dmatx->sg.length = count; + + if (dma_map_sg(dma_dev->dev, &dmatx->sg, 1, DMA_TO_DEVICE) != 1) { + uap->dmatx.queued = false; + dev_dbg(uap->port.dev, "unable to map TX DMA\n"); + return -EBUSY; + } + + desc = dma_dev->device_prep_slave_sg(chan, &dmatx->sg, 1, DMA_TO_DEVICE, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!desc) { + dma_unmap_sg(dma_dev->dev, &dmatx->sg, 1, DMA_TO_DEVICE); + uap->dmatx.queued = false; + /* + * If DMA cannot be used right now, we complete this + * transaction via IRQ and let the TTY layer retry. + */ + dev_dbg(uap->port.dev, "TX DMA busy\n"); + return -EBUSY; + } + + /* Some data to go along to the callback */ + desc->callback = pl011_dma_tx_callback; + desc->callback_param = uap; + + /* All errors should happen at prepare time */ + dmaengine_submit(desc); + + /* Fire the DMA transaction */ + dma_dev->device_issue_pending(chan); + + uap->dmacr |= UART011_TXDMAE; + writew(uap->dmacr, uap->port.membase + UART011_DMACR); + uap->dmatx.queued = true; + + /* + * Now we know that DMA will fire, so advance the ring buffer + * with the stuff we just dispatched. + */ + xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1); + uap->port.icount.tx += count; + + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + uart_write_wakeup(&uap->port); + + return 1; +} + +/* + * We received a transmit interrupt without a pending X-char but with + * pending characters. + * Locking: called with port lock held and IRQs disabled. + * Returns: + * false if we want to use PIO to transmit + * true if we queued a DMA buffer + */ +static bool pl011_dma_tx_irq(struct uart_amba_port *uap) +{ + if (!uap->using_dma) + return false; + + /* + * If we already have a TX buffer queued, but received a + * TX interrupt, it will be because we've just sent an X-char. + * Ensure the TX DMA is enabled and the TX IRQ is disabled. + */ + if (uap->dmatx.queued) { + uap->dmacr |= UART011_TXDMAE; + writew(uap->dmacr, uap->port.membase + UART011_DMACR); + uap->im &= ~UART011_TXIM; + writew(uap->im, uap->port.membase + UART011_IMSC); + return true; + } + + /* + * We don't have a TX buffer queued, so try to queue one. + * If we succesfully queued a buffer, mask the TX IRQ. + */ + if (pl011_dma_tx_refill(uap) > 0) { + uap->im &= ~UART011_TXIM; + writew(uap->im, uap->port.membase + UART011_IMSC); + return true; + } + return false; +} + +/* + * Stop the DMA transmit (eg, due to received XOFF). + * Locking: called with port lock held and IRQs disabled. + */ +static inline void pl011_dma_tx_stop(struct uart_amba_port *uap) +{ + if (uap->dmatx.queued) { + uap->dmacr &= ~UART011_TXDMAE; + writew(uap->dmacr, uap->port.membase + UART011_DMACR); + } +} + +/* + * Try to start a DMA transmit, or in the case of an XON/OFF + * character queued for send, try to get that character out ASAP. + * Locking: called with port lock held and IRQs disabled. + * Returns: + * false if we want the TX IRQ to be enabled + * true if we have a buffer queued + */ +static inline bool pl011_dma_tx_start(struct uart_amba_port *uap) +{ + u16 dmacr; + + if (!uap->using_dma) + return false; + + if (!uap->port.x_char) { + /* no X-char, try to push chars out in DMA mode */ + bool ret = true; + + if (!uap->dmatx.queued) { + if (pl011_dma_tx_refill(uap) > 0) { + uap->im &= ~UART011_TXIM; + ret = true; + } else { + uap->im |= UART011_TXIM; + ret = false; + } + writew(uap->im, uap->port.membase + UART011_IMSC); + } else if (!(uap->dmacr & UART011_TXDMAE)) { + uap->dmacr |= UART011_TXDMAE; + writew(uap->dmacr, + uap->port.membase + UART011_DMACR); + } + return ret; + } + + /* + * We have an X-char to send. Disable DMA to prevent it loading + * the TX fifo, and then see if we can stuff it into the FIFO. + */ + dmacr = uap->dmacr; + uap->dmacr &= ~UART011_TXDMAE; + writew(uap->dmacr, uap->port.membase + UART011_DMACR); + + if (readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF) { + /* + * No space in the FIFO, so enable the transmit interrupt + * so we know when there is space. Note that once we've + * loaded the character, we should just re-enable DMA. + */ + return false; + } + + writew(uap->port.x_char, uap->port.membase + UART01x_DR); + uap->port.icount.tx++; + uap->port.x_char = 0; + + /* Success - restore the DMA state */ + uap->dmacr = dmacr; + writew(dmacr, uap->port.membase + UART011_DMACR); + + return true; +} + +/* + * Flush the transmit buffer. + * Locking: called with port lock held and IRQs disabled. + */ +static void pl011_dma_flush_buffer(struct uart_port *port) +{ + struct uart_amba_port *uap = (struct uart_amba_port *)port; + + if (!uap->using_dma) + return; + + /* Avoid deadlock with the DMA engine callback */ + spin_unlock(&uap->port.lock); + dmaengine_terminate_all(uap->dmatx.chan); + spin_lock(&uap->port.lock); + if (uap->dmatx.queued) { + dma_unmap_sg(uap->dmatx.chan->device->dev, &uap->dmatx.sg, 1, + DMA_TO_DEVICE); + uap->dmatx.queued = false; + uap->dmacr &= ~UART011_TXDMAE; + writew(uap->dmacr, uap->port.membase + UART011_DMACR); + } +} + + +static void pl011_dma_startup(struct uart_amba_port *uap) +{ + if (!uap->dmatx.chan) + return; + + uap->dmatx.buf = kmalloc(PL011_DMA_BUFFER_SIZE, GFP_KERNEL); + if (!uap->dmatx.buf) { + dev_err(uap->port.dev, "no memory for DMA TX buffer\n"); + uap->port.fifosize = uap->fifosize; + return; + } + + sg_init_one(&uap->dmatx.sg, uap->dmatx.buf, PL011_DMA_BUFFER_SIZE); + + /* The DMA buffer is now the FIFO the TTY subsystem can use */ + uap->port.fifosize = PL011_DMA_BUFFER_SIZE; + uap->using_dma = true; + + /* Turn on DMA error (RX/TX will be enabled on demand) */ + uap->dmacr |= UART011_DMAONERR; + writew(uap->dmacr, uap->port.membase + UART011_DMACR); + + /* + * ST Micro variants has some specific dma burst threshold + * compensation. Set this to 16 bytes, so burst will only + * be issued above/below 16 bytes. + */ + if (uap->vendor->dma_threshold) + writew(ST_UART011_DMAWM_RX_16 | ST_UART011_DMAWM_TX_16, + uap->port.membase + ST_UART011_DMAWM); +} + +static void pl011_dma_shutdown(struct uart_amba_port *uap) +{ + if (!uap->using_dma) + return; + + /* Disable RX and TX DMA */ + while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_BUSY) + barrier(); + + spin_lock_irq(&uap->port.lock); + uap->dmacr &= ~(UART011_DMAONERR | UART011_RXDMAE | UART011_TXDMAE); + writew(uap->dmacr, uap->port.membase + UART011_DMACR); + spin_unlock_irq(&uap->port.lock); + + /* In theory, this should already be done by pl011_dma_flush_buffer */ + dmaengine_terminate_all(uap->dmatx.chan); + if (uap->dmatx.queued) { + dma_unmap_sg(uap->dmatx.chan->device->dev, &uap->dmatx.sg, 1, + DMA_TO_DEVICE); + uap->dmatx.queued = false; + } + + kfree(uap->dmatx.buf); + + uap->using_dma = false; +} + +#else +/* Blank functions if the DMA engine is not available */ +static inline void pl011_dma_probe(struct uart_amba_port *uap) +{ +} + +static inline void pl011_dma_remove(struct uart_amba_port *uap) +{ +} + +static inline void pl011_dma_startup(struct uart_amba_port *uap) +{ +} + +static inline void pl011_dma_shutdown(struct uart_amba_port *uap) +{ +} + +static inline bool pl011_dma_tx_irq(struct uart_amba_port *uap) +{ + return false; +} + +static inline void pl011_dma_tx_stop(struct uart_amba_port *uap) +{ +} + +static inline bool pl011_dma_tx_start(struct uart_amba_port *uap) +{ + return false; +} + +#define pl011_dma_flush_buffer NULL +#endif + + +static void pl011_stop_tx(struct uart_port *port) +{ + struct uart_amba_port *uap = (struct uart_amba_port *)port; + + uap->im &= ~UART011_TXIM; + writew(uap->im, uap->port.membase + UART011_IMSC); + pl011_dma_tx_stop(uap); +} + +static void pl011_start_tx(struct uart_port *port) +{ + struct uart_amba_port *uap = (struct uart_amba_port *)port; + + if (!pl011_dma_tx_start(uap)) { + uap->im |= UART011_TXIM; + writew(uap->im, uap->port.membase + UART011_IMSC); + } +} + +static void pl011_stop_rx(struct uart_port *port) +{ + struct uart_amba_port *uap = (struct uart_amba_port *)port; + + uap->im &= ~(UART011_RXIM|UART011_RTIM|UART011_FEIM| + UART011_PEIM|UART011_BEIM|UART011_OEIM); + writew(uap->im, uap->port.membase + UART011_IMSC); +} + +static void pl011_enable_ms(struct uart_port *port) +{ + struct uart_amba_port *uap = (struct uart_amba_port *)port; + + uap->im |= UART011_RIMIM|UART011_CTSMIM|UART011_DCDMIM|UART011_DSRMIM; + writew(uap->im, uap->port.membase + UART011_IMSC); +} + +static void pl011_rx_chars(struct uart_amba_port *uap) +{ + struct tty_struct *tty = uap->port.state->port.tty; + unsigned int status, ch, flag, max_count = 256; + + status = readw(uap->port.membase + UART01x_FR); + while ((status & UART01x_FR_RXFE) == 0 && max_count--) { + ch = readw(uap->port.membase + UART01x_DR) | UART_DUMMY_DR_RX; + flag = TTY_NORMAL; + uap->port.icount.rx++; + + /* + * Note that the error handling code is + * out of the main execution path + */ + if (unlikely(ch & UART_DR_ERROR)) { + if (ch & UART011_DR_BE) { + ch &= ~(UART011_DR_FE | UART011_DR_PE); + uap->port.icount.brk++; + if (uart_handle_break(&uap->port)) + goto ignore_char; + } else if (ch & UART011_DR_PE) + uap->port.icount.parity++; + else if (ch & UART011_DR_FE) + uap->port.icount.frame++; + if (ch & UART011_DR_OE) + uap->port.icount.overrun++; + + ch &= uap->port.read_status_mask; + + if (ch & UART011_DR_BE) + flag = TTY_BREAK; + else if (ch & UART011_DR_PE) + flag = TTY_PARITY; + else if (ch & UART011_DR_FE) + flag = TTY_FRAME; + } + + if (uart_handle_sysrq_char(&uap->port, ch & 255)) + goto ignore_char; + + uart_insert_char(&uap->port, ch, UART011_DR_OE, ch, flag); + + ignore_char: + status = readw(uap->port.membase + UART01x_FR); + } + spin_unlock(&uap->port.lock); + tty_flip_buffer_push(tty); + spin_lock(&uap->port.lock); +} + +static void pl011_tx_chars(struct uart_amba_port *uap) +{ + struct circ_buf *xmit = &uap->port.state->xmit; + int count; + + if (uap->port.x_char) { + writew(uap->port.x_char, uap->port.membase + UART01x_DR); + uap->port.icount.tx++; + uap->port.x_char = 0; + return; + } + if (uart_circ_empty(xmit) || uart_tx_stopped(&uap->port)) { + pl011_stop_tx(&uap->port); + return; + } + + /* If we are using DMA mode, try to send some characters. */ + if (pl011_dma_tx_irq(uap)) + return; + + count = uap->fifosize >> 1; + do { + writew(xmit->buf[xmit->tail], uap->port.membase + UART01x_DR); + xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); + uap->port.icount.tx++; + if (uart_circ_empty(xmit)) + break; + } while (--count > 0); + + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + uart_write_wakeup(&uap->port); + + if (uart_circ_empty(xmit)) + pl011_stop_tx(&uap->port); +} + +static void pl011_modem_status(struct uart_amba_port *uap) +{ + unsigned int status, delta; + + status = readw(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY; + + delta = status ^ uap->old_status; + uap->old_status = status; + + if (!delta) + return; + + if (delta & UART01x_FR_DCD) + uart_handle_dcd_change(&uap->port, status & UART01x_FR_DCD); + + if (delta & UART01x_FR_DSR) + uap->port.icount.dsr++; + + if (delta & UART01x_FR_CTS) + uart_handle_cts_change(&uap->port, status & UART01x_FR_CTS); + + wake_up_interruptible(&uap->port.state->port.delta_msr_wait); +} + +static irqreturn_t pl011_int(int irq, void *dev_id) +{ + struct uart_amba_port *uap = dev_id; + unsigned long flags; + unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT; + int handled = 0; + + spin_lock_irqsave(&uap->port.lock, flags); + + status = readw(uap->port.membase + UART011_MIS); + if (status) { + do { + writew(status & ~(UART011_TXIS|UART011_RTIS| + UART011_RXIS), + uap->port.membase + UART011_ICR); + + if (status & (UART011_RTIS|UART011_RXIS)) + pl011_rx_chars(uap); + if (status & (UART011_DSRMIS|UART011_DCDMIS| + UART011_CTSMIS|UART011_RIMIS)) + pl011_modem_status(uap); + if (status & UART011_TXIS) + pl011_tx_chars(uap); + + if (pass_counter-- == 0) + break; + + status = readw(uap->port.membase + UART011_MIS); + } while (status != 0); + handled = 1; + } + + spin_unlock_irqrestore(&uap->port.lock, flags); + + return IRQ_RETVAL(handled); +} + +static unsigned int pl01x_tx_empty(struct uart_port *port) +{ + struct uart_amba_port *uap = (struct uart_amba_port *)port; + unsigned int status = readw(uap->port.membase + UART01x_FR); + return status & (UART01x_FR_BUSY|UART01x_FR_TXFF) ? 0 : TIOCSER_TEMT; +} + +static unsigned int pl01x_get_mctrl(struct uart_port *port) +{ + struct uart_amba_port *uap = (struct uart_amba_port *)port; + unsigned int result = 0; + unsigned int status = readw(uap->port.membase + UART01x_FR); + +#define TIOCMBIT(uartbit, tiocmbit) \ + if (status & uartbit) \ + result |= tiocmbit + + TIOCMBIT(UART01x_FR_DCD, TIOCM_CAR); + TIOCMBIT(UART01x_FR_DSR, TIOCM_DSR); + TIOCMBIT(UART01x_FR_CTS, TIOCM_CTS); + TIOCMBIT(UART011_FR_RI, TIOCM_RNG); +#undef TIOCMBIT + return result; +} + +static void pl011_set_mctrl(struct uart_port *port, unsigned int mctrl) +{ + struct uart_amba_port *uap = (struct uart_amba_port *)port; + unsigned int cr; + + cr = readw(uap->port.membase + UART011_CR); + +#define TIOCMBIT(tiocmbit, uartbit) \ + if (mctrl & tiocmbit) \ + cr |= uartbit; \ + else \ + cr &= ~uartbit + + TIOCMBIT(TIOCM_RTS, UART011_CR_RTS); + TIOCMBIT(TIOCM_DTR, UART011_CR_DTR); + TIOCMBIT(TIOCM_OUT1, UART011_CR_OUT1); + TIOCMBIT(TIOCM_OUT2, UART011_CR_OUT2); + TIOCMBIT(TIOCM_LOOP, UART011_CR_LBE); + + if (uap->autorts) { + /* We need to disable auto-RTS if we want to turn RTS off */ + TIOCMBIT(TIOCM_RTS, UART011_CR_RTSEN); + } +#undef TIOCMBIT + + writew(cr, uap->port.membase + UART011_CR); +} + +static void pl011_break_ctl(struct uart_port *port, int break_state) +{ + struct uart_amba_port *uap = (struct uart_amba_port *)port; + unsigned long flags; + unsigned int lcr_h; + + spin_lock_irqsave(&uap->port.lock, flags); + lcr_h = readw(uap->port.membase + uap->lcrh_tx); + if (break_state == -1) + lcr_h |= UART01x_LCRH_BRK; + else + lcr_h &= ~UART01x_LCRH_BRK; + writew(lcr_h, uap->port.membase + uap->lcrh_tx); + spin_unlock_irqrestore(&uap->port.lock, flags); +} + +#ifdef CONFIG_CONSOLE_POLL +static int pl010_get_poll_char(struct uart_port *port) +{ + struct uart_amba_port *uap = (struct uart_amba_port *)port; + unsigned int status; + + status = readw(uap->port.membase + UART01x_FR); + if (status & UART01x_FR_RXFE) + return NO_POLL_CHAR; + + return readw(uap->port.membase + UART01x_DR); +} + +static void pl010_put_poll_char(struct uart_port *port, + unsigned char ch) +{ + struct uart_amba_port *uap = (struct uart_amba_port *)port; + + while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF) + barrier(); + + writew(ch, uap->port.membase + UART01x_DR); +} + +#endif /* CONFIG_CONSOLE_POLL */ + +static int pl011_startup(struct uart_port *port) +{ + struct uart_amba_port *uap = (struct uart_amba_port *)port; + unsigned int cr; + int retval; + + /* + * Try to enable the clock producer. + */ + retval = clk_enable(uap->clk); + if (retval) + goto out; + + uap->port.uartclk = clk_get_rate(uap->clk); + + /* + * Allocate the IRQ + */ + retval = request_irq(uap->port.irq, pl011_int, 0, "uart-pl011", uap); + if (retval) + goto clk_dis; + + writew(uap->vendor->ifls, uap->port.membase + UART011_IFLS); + + /* + * Provoke TX FIFO interrupt into asserting. + */ + cr = UART01x_CR_UARTEN | UART011_CR_TXE | UART011_CR_LBE; + writew(cr, uap->port.membase + UART011_CR); + writew(0, uap->port.membase + UART011_FBRD); + writew(1, uap->port.membase + UART011_IBRD); + writew(0, uap->port.membase + uap->lcrh_rx); + if (uap->lcrh_tx != uap->lcrh_rx) { + int i; + /* + * Wait 10 PCLKs before writing LCRH_TX register, + * to get this delay write read only register 10 times + */ + for (i = 0; i < 10; ++i) + writew(0xff, uap->port.membase + UART011_MIS); + writew(0, uap->port.membase + uap->lcrh_tx); + } + writew(0, uap->port.membase + UART01x_DR); + while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_BUSY) + barrier(); + + cr = UART01x_CR_UARTEN | UART011_CR_RXE | UART011_CR_TXE; + writew(cr, uap->port.membase + UART011_CR); + + /* Clear pending error interrupts */ + writew(UART011_OEIS | UART011_BEIS | UART011_PEIS | UART011_FEIS, + uap->port.membase + UART011_ICR); + + /* + * initialise the old status of the modem signals + */ + uap->old_status = readw(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY; + + /* Startup DMA */ + pl011_dma_startup(uap); + + /* + * Finally, enable interrupts + */ + spin_lock_irq(&uap->port.lock); + uap->im = UART011_RXIM | UART011_RTIM; + writew(uap->im, uap->port.membase + UART011_IMSC); + spin_unlock_irq(&uap->port.lock); + + return 0; + + clk_dis: + clk_disable(uap->clk); + out: + return retval; +} + +static void pl011_shutdown_channel(struct uart_amba_port *uap, + unsigned int lcrh) +{ + unsigned long val; + + val = readw(uap->port.membase + lcrh); + val &= ~(UART01x_LCRH_BRK | UART01x_LCRH_FEN); + writew(val, uap->port.membase + lcrh); +} + +static void pl011_shutdown(struct uart_port *port) +{ + struct uart_amba_port *uap = (struct uart_amba_port *)port; + + /* + * disable all interrupts + */ + spin_lock_irq(&uap->port.lock); + uap->im = 0; + writew(uap->im, uap->port.membase + UART011_IMSC); + writew(0xffff, uap->port.membase + UART011_ICR); + spin_unlock_irq(&uap->port.lock); + + pl011_dma_shutdown(uap); + + /* + * Free the interrupt + */ + free_irq(uap->port.irq, uap); + + /* + * disable the port + */ + uap->autorts = false; + writew(UART01x_CR_UARTEN | UART011_CR_TXE, uap->port.membase + UART011_CR); + + /* + * disable break condition and fifos + */ + pl011_shutdown_channel(uap, uap->lcrh_rx); + if (uap->lcrh_rx != uap->lcrh_tx) + pl011_shutdown_channel(uap, uap->lcrh_tx); + + /* + * Shut down the clock producer + */ + clk_disable(uap->clk); +} + +static void +pl011_set_termios(struct uart_port *port, struct ktermios *termios, + struct ktermios *old) +{ + struct uart_amba_port *uap = (struct uart_amba_port *)port; + unsigned int lcr_h, old_cr; + unsigned long flags; + unsigned int baud, quot, clkdiv; + + if (uap->vendor->oversampling) + clkdiv = 8; + else + clkdiv = 16; + + /* + * Ask the core to calculate the divisor for us. + */ + baud = uart_get_baud_rate(port, termios, old, 0, + port->uartclk / clkdiv); + + if (baud > port->uartclk/16) + quot = DIV_ROUND_CLOSEST(port->uartclk * 8, baud); + else + quot = DIV_ROUND_CLOSEST(port->uartclk * 4, baud); + + switch (termios->c_cflag & CSIZE) { + case CS5: + lcr_h = UART01x_LCRH_WLEN_5; + break; + case CS6: + lcr_h = UART01x_LCRH_WLEN_6; + break; + case CS7: + lcr_h = UART01x_LCRH_WLEN_7; + break; + default: // CS8 + lcr_h = UART01x_LCRH_WLEN_8; + break; + } + if (termios->c_cflag & CSTOPB) + lcr_h |= UART01x_LCRH_STP2; + if (termios->c_cflag & PARENB) { + lcr_h |= UART01x_LCRH_PEN; + if (!(termios->c_cflag & PARODD)) + lcr_h |= UART01x_LCRH_EPS; + } + if (uap->fifosize > 1) + lcr_h |= UART01x_LCRH_FEN; + + spin_lock_irqsave(&port->lock, flags); + + /* + * Update the per-port timeout. + */ + uart_update_timeout(port, termios->c_cflag, baud); + + port->read_status_mask = UART011_DR_OE | 255; + if (termios->c_iflag & INPCK) + port->read_status_mask |= UART011_DR_FE | UART011_DR_PE; + if (termios->c_iflag & (BRKINT | PARMRK)) + port->read_status_mask |= UART011_DR_BE; + + /* + * Characters to ignore + */ + port->ignore_status_mask = 0; + if (termios->c_iflag & IGNPAR) + port->ignore_status_mask |= UART011_DR_FE | UART011_DR_PE; + if (termios->c_iflag & IGNBRK) { + port->ignore_status_mask |= UART011_DR_BE; + /* + * If we're ignoring parity and break indicators, + * ignore overruns too (for real raw support). + */ + if (termios->c_iflag & IGNPAR) + port->ignore_status_mask |= UART011_DR_OE; + } + + /* + * Ignore all characters if CREAD is not set. + */ + if ((termios->c_cflag & CREAD) == 0) + port->ignore_status_mask |= UART_DUMMY_DR_RX; + + if (UART_ENABLE_MS(port, termios->c_cflag)) + pl011_enable_ms(port); + + /* first, disable everything */ + old_cr = readw(port->membase + UART011_CR); + writew(0, port->membase + UART011_CR); + + if (termios->c_cflag & CRTSCTS) { + if (old_cr & UART011_CR_RTS) + old_cr |= UART011_CR_RTSEN; + + old_cr |= UART011_CR_CTSEN; + uap->autorts = true; + } else { + old_cr &= ~(UART011_CR_CTSEN | UART011_CR_RTSEN); + uap->autorts = false; + } + + if (uap->vendor->oversampling) { + if (baud > port->uartclk / 16) + old_cr |= ST_UART011_CR_OVSFACT; + else + old_cr &= ~ST_UART011_CR_OVSFACT; + } + + /* Set baud rate */ + writew(quot & 0x3f, port->membase + UART011_FBRD); + writew(quot >> 6, port->membase + UART011_IBRD); + + /* + * ----------v----------v----------v----------v----- + * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L + * ----------^----------^----------^----------^----- + */ + writew(lcr_h, port->membase + uap->lcrh_rx); + if (uap->lcrh_rx != uap->lcrh_tx) { + int i; + /* + * Wait 10 PCLKs before writing LCRH_TX register, + * to get this delay write read only register 10 times + */ + for (i = 0; i < 10; ++i) + writew(0xff, uap->port.membase + UART011_MIS); + writew(lcr_h, port->membase + uap->lcrh_tx); + } + writew(old_cr, port->membase + UART011_CR); + + spin_unlock_irqrestore(&port->lock, flags); +} + +static const char *pl011_type(struct uart_port *port) +{ + struct uart_amba_port *uap = (struct uart_amba_port *)port; + return uap->port.type == PORT_AMBA ? uap->type : NULL; +} + +/* + * Release the memory region(s) being used by 'port' + */ +static void pl010_release_port(struct uart_port *port) +{ + release_mem_region(port->mapbase, SZ_4K); +} + +/* + * Request the memory region(s) being used by 'port' + */ +static int pl010_request_port(struct uart_port *port) +{ + return request_mem_region(port->mapbase, SZ_4K, "uart-pl011") + != NULL ? 0 : -EBUSY; +} + +/* + * Configure/autoconfigure the port. + */ +static void pl010_config_port(struct uart_port *port, int flags) +{ + if (flags & UART_CONFIG_TYPE) { + port->type = PORT_AMBA; + pl010_request_port(port); + } +} + +/* + * verify the new serial_struct (for TIOCSSERIAL). + */ +static int pl010_verify_port(struct uart_port *port, struct serial_struct *ser) +{ + int ret = 0; + if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA) + ret = -EINVAL; + if (ser->irq < 0 || ser->irq >= nr_irqs) + ret = -EINVAL; + if (ser->baud_base < 9600) + ret = -EINVAL; + return ret; +} + +static struct uart_ops amba_pl011_pops = { + .tx_empty = pl01x_tx_empty, + .set_mctrl = pl011_set_mctrl, + .get_mctrl = pl01x_get_mctrl, + .stop_tx = pl011_stop_tx, + .start_tx = pl011_start_tx, + .stop_rx = pl011_stop_rx, + .enable_ms = pl011_enable_ms, + .break_ctl = pl011_break_ctl, + .startup = pl011_startup, + .shutdown = pl011_shutdown, + .flush_buffer = pl011_dma_flush_buffer, + .set_termios = pl011_set_termios, + .type = pl011_type, + .release_port = pl010_release_port, + .request_port = pl010_request_port, + .config_port = pl010_config_port, + .verify_port = pl010_verify_port, +#ifdef CONFIG_CONSOLE_POLL + .poll_get_char = pl010_get_poll_char, + .poll_put_char = pl010_put_poll_char, +#endif +}; + +static struct uart_amba_port *amba_ports[UART_NR]; + +#ifdef CONFIG_SERIAL_AMBA_PL011_CONSOLE + +static void pl011_console_putchar(struct uart_port *port, int ch) +{ + struct uart_amba_port *uap = (struct uart_amba_port *)port; + + while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF) + barrier(); + writew(ch, uap->port.membase + UART01x_DR); +} + +static void +pl011_console_write(struct console *co, const char *s, unsigned int count) +{ + struct uart_amba_port *uap = amba_ports[co->index]; + unsigned int status, old_cr, new_cr; + + clk_enable(uap->clk); + + /* + * First save the CR then disable the interrupts + */ + old_cr = readw(uap->port.membase + UART011_CR); + new_cr = old_cr & ~UART011_CR_CTSEN; + new_cr |= UART01x_CR_UARTEN | UART011_CR_TXE; + writew(new_cr, uap->port.membase + UART011_CR); + + uart_console_write(&uap->port, s, count, pl011_console_putchar); + + /* + * Finally, wait for transmitter to become empty + * and restore the TCR + */ + do { + status = readw(uap->port.membase + UART01x_FR); + } while (status & UART01x_FR_BUSY); + writew(old_cr, uap->port.membase + UART011_CR); + + clk_disable(uap->clk); +} + +static void __init +pl011_console_get_options(struct uart_amba_port *uap, int *baud, + int *parity, int *bits) +{ + if (readw(uap->port.membase + UART011_CR) & UART01x_CR_UARTEN) { + unsigned int lcr_h, ibrd, fbrd; + + lcr_h = readw(uap->port.membase + uap->lcrh_tx); + + *parity = 'n'; + if (lcr_h & UART01x_LCRH_PEN) { + if (lcr_h & UART01x_LCRH_EPS) + *parity = 'e'; + else + *parity = 'o'; + } + + if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7) + *bits = 7; + else + *bits = 8; + + ibrd = readw(uap->port.membase + UART011_IBRD); + fbrd = readw(uap->port.membase + UART011_FBRD); + + *baud = uap->port.uartclk * 4 / (64 * ibrd + fbrd); + + if (uap->vendor->oversampling) { + if (readw(uap->port.membase + UART011_CR) + & ST_UART011_CR_OVSFACT) + *baud *= 2; + } + } +} + +static int __init pl011_console_setup(struct console *co, char *options) +{ + struct uart_amba_port *uap; + int baud = 38400; + int bits = 8; + int parity = 'n'; + int flow = 'n'; + + /* + * Check whether an invalid uart number has been specified, and + * if so, search for the first available port that does have + * console support. + */ + if (co->index >= UART_NR) + co->index = 0; + uap = amba_ports[co->index]; + if (!uap) + return -ENODEV; + + uap->port.uartclk = clk_get_rate(uap->clk); + + if (options) + uart_parse_options(options, &baud, &parity, &bits, &flow); + else + pl011_console_get_options(uap, &baud, &parity, &bits); + + return uart_set_options(&uap->port, co, baud, parity, bits, flow); +} + +static struct uart_driver amba_reg; +static struct console amba_console = { + .name = "ttyAMA", + .write = pl011_console_write, + .device = uart_console_device, + .setup = pl011_console_setup, + .flags = CON_PRINTBUFFER, + .index = -1, + .data = &amba_reg, +}; + +#define AMBA_CONSOLE (&amba_console) +#else +#define AMBA_CONSOLE NULL +#endif + +static struct uart_driver amba_reg = { + .owner = THIS_MODULE, + .driver_name = "ttyAMA", + .dev_name = "ttyAMA", + .major = SERIAL_AMBA_MAJOR, + .minor = SERIAL_AMBA_MINOR, + .nr = UART_NR, + .cons = AMBA_CONSOLE, +}; + +static int pl011_probe(struct amba_device *dev, struct amba_id *id) +{ + struct uart_amba_port *uap; + struct vendor_data *vendor = id->data; + void __iomem *base; + int i, ret; + + for (i = 0; i < ARRAY_SIZE(amba_ports); i++) + if (amba_ports[i] == NULL) + break; + + if (i == ARRAY_SIZE(amba_ports)) { + ret = -EBUSY; + goto out; + } + + uap = kzalloc(sizeof(struct uart_amba_port), GFP_KERNEL); + if (uap == NULL) { + ret = -ENOMEM; + goto out; + } + + base = ioremap(dev->res.start, resource_size(&dev->res)); + if (!base) { + ret = -ENOMEM; + goto free; + } + + uap->clk = clk_get(&dev->dev, NULL); + if (IS_ERR(uap->clk)) { + ret = PTR_ERR(uap->clk); + goto unmap; + } + + uap->vendor = vendor; + uap->lcrh_rx = vendor->lcrh_rx; + uap->lcrh_tx = vendor->lcrh_tx; + uap->fifosize = vendor->fifosize; + uap->port.dev = &dev->dev; + uap->port.mapbase = dev->res.start; + uap->port.membase = base; + uap->port.iotype = UPIO_MEM; + uap->port.irq = dev->irq[0]; + uap->port.fifosize = uap->fifosize; + uap->port.ops = &amba_pl011_pops; + uap->port.flags = UPF_BOOT_AUTOCONF; + uap->port.line = i; + pl011_dma_probe(uap); + + snprintf(uap->type, sizeof(uap->type), "PL011 rev%u", amba_rev(dev)); + + amba_ports[i] = uap; + + amba_set_drvdata(dev, uap); + ret = uart_add_one_port(&amba_reg, &uap->port); + if (ret) { + amba_set_drvdata(dev, NULL); + amba_ports[i] = NULL; + pl011_dma_remove(uap); + clk_put(uap->clk); + unmap: + iounmap(base); + free: + kfree(uap); + } + out: + return ret; +} + +static int pl011_remove(struct amba_device *dev) +{ + struct uart_amba_port *uap = amba_get_drvdata(dev); + int i; + + amba_set_drvdata(dev, NULL); + + uart_remove_one_port(&amba_reg, &uap->port); + + for (i = 0; i < ARRAY_SIZE(amba_ports); i++) + if (amba_ports[i] == uap) + amba_ports[i] = NULL; + + pl011_dma_remove(uap); + iounmap(uap->port.membase); + clk_put(uap->clk); + kfree(uap); + return 0; +} + +#ifdef CONFIG_PM +static int pl011_suspend(struct amba_device *dev, pm_message_t state) +{ + struct uart_amba_port *uap = amba_get_drvdata(dev); + + if (!uap) + return -EINVAL; + + return uart_suspend_port(&amba_reg, &uap->port); +} + +static int pl011_resume(struct amba_device *dev) +{ + struct uart_amba_port *uap = amba_get_drvdata(dev); + + if (!uap) + return -EINVAL; + + return uart_resume_port(&amba_reg, &uap->port); +} +#endif + +static struct amba_id pl011_ids[] = { + { + .id = 0x00041011, + .mask = 0x000fffff, + .data = &vendor_arm, + }, + { + .id = 0x00380802, + .mask = 0x00ffffff, + .data = &vendor_st, + }, + { 0, 0 }, +}; + +static struct amba_driver pl011_driver = { + .drv = { + .name = "uart-pl011", + }, + .id_table = pl011_ids, + .probe = pl011_probe, + .remove = pl011_remove, +#ifdef CONFIG_PM + .suspend = pl011_suspend, + .resume = pl011_resume, +#endif +}; + +static int __init pl011_init(void) +{ + int ret; + printk(KERN_INFO "Serial: AMBA PL011 UART driver\n"); + + ret = uart_register_driver(&amba_reg); + if (ret == 0) { + ret = amba_driver_register(&pl011_driver); + if (ret) + uart_unregister_driver(&amba_reg); + } + return ret; +} + +static void __exit pl011_exit(void) +{ + amba_driver_unregister(&pl011_driver); + uart_unregister_driver(&amba_reg); +} + +/* + * While this can be a module, if builtin it's most likely the console + * So let's leave module_exit but move module_init to an earlier place + */ +arch_initcall(pl011_init); +module_exit(pl011_exit); + +MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd"); +MODULE_DESCRIPTION("ARM AMBA serial port driver"); +MODULE_LICENSE("GPL"); |
