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authorRussell King <rmk+kernel@arm.linux.org.uk>2012-04-25 00:16:00 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2012-07-31 12:06:24 +0100
commit763e735910922382c2577e820e2a51df0a7cf17c (patch)
treef03b8e03378eccd75f11e276742e56b21f27a4c1 /drivers/mtd
parent8c7494a501bd45e1bf1599a51331b1c210cadbae (diff)
downloadop-kernel-dev-763e735910922382c2577e820e2a51df0a7cf17c.zip
op-kernel-dev-763e735910922382c2577e820e2a51df0a7cf17c.tar.gz
mtd: omap2: add DMA engine support
Add DMA engine support to the OMAP2 NAND driver. This supplements the private DMA API implementation contained within this driver, and the driver can be independently switched at build time between using DMA engine and the private DMA API. Tested-by: Grazvydas Ignotas <notasas@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'drivers/mtd')
-rw-r--r--drivers/mtd/nand/omap2.c92
1 files changed, 91 insertions, 1 deletions
diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index d7f681d..2912d6c 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -9,6 +9,7 @@
*/
#include <linux/platform_device.h>
+#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/delay.h>
#include <linux/module.h>
@@ -18,6 +19,7 @@
#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
#include <linux/mtd/partitions.h>
+#include <linux/omap-dma.h>
#include <linux/io.h>
#include <linux/slab.h>
@@ -123,6 +125,7 @@ struct omap_nand_info {
int gpmc_cs;
unsigned long phys_base;
struct completion comp;
+ struct dma_chan *dma;
int dma_ch;
int gpmc_irq;
enum {
@@ -345,6 +348,10 @@ static void omap_nand_dma_cb(int lch, u16 ch_status, void *data)
{
complete((struct completion *) data);
}
+static void omap_nand_dma_callback(void *data)
+{
+ complete((struct completion *) data);
+}
/*
* omap_nand_dma_transfer: configer and start dma transfer
@@ -382,6 +389,56 @@ static inline int omap_nand_dma_transfer(struct mtd_info *mtd, void *addr,
addr = page_address(p1) + ((size_t)addr & ~PAGE_MASK);
}
+ if (info->dma) {
+ struct dma_async_tx_descriptor *tx;
+ struct scatterlist sg;
+ unsigned n;
+
+ sg_init_one(&sg, addr, len);
+ n = dma_map_sg(info->dma->device->dev, &sg, 1, dir);
+ if (n == 0) {
+ dev_err(&info->pdev->dev,
+ "Couldn't DMA map a %d byte buffer\n", len);
+ goto out_copy;
+ }
+
+ tx = dmaengine_prep_slave_sg(info->dma, &sg, n,
+ is_write ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+ if (!tx) {
+ dma_unmap_sg(info->dma->device->dev, &sg, 1, dir);
+ goto out_copy;
+ }
+ tx->callback = omap_nand_dma_callback;
+ tx->callback_param = &info->comp;
+ dmaengine_submit(tx);
+
+ /* configure and start prefetch transfer */
+ ret = gpmc_prefetch_enable(info->gpmc_cs,
+ PREFETCH_FIFOTHRESHOLD_MAX, 0x1, len, is_write);
+ if (ret) {
+ /* PFPW engine is busy, use cpu copy method */
+ dma_unmap_sg(info->dma->device->dev, &sg, 1, dir);
+ goto out_copy;
+ }
+
+ init_completion(&info->comp);
+ dma_async_issue_pending(info->dma);
+
+ /* setup and start DMA using dma_addr */
+ wait_for_completion(&info->comp);
+ tim = 0;
+ limit = (loops_per_jiffy * msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
+ while (gpmc_read_status(GPMC_PREFETCH_COUNT) && (tim++ < limit))
+ cpu_relax();
+
+ /* disable and stop the PFPW engine */
+ gpmc_prefetch_reset(info->gpmc_cs);
+
+ dma_unmap_sg(info->dma->device->dev, &sg, 1, dir);
+ return 0;
+ }
+
dma_addr = dma_map_single(&info->pdev->dev, addr, len, dir);
if (dma_mapping_error(&info->pdev->dev, dma_addr)) {
dev_err(&info->pdev->dev,
@@ -414,7 +471,6 @@ static inline int omap_nand_dma_transfer(struct mtd_info *mtd, void *addr,
goto out_copy_unmap;
init_completion(&info->comp);
-
omap_start_dma(info->dma_ch);
/* setup and start DMA using dma_addr */
@@ -1164,6 +1220,8 @@ static int __devinit omap_nand_probe(struct platform_device *pdev)
struct omap_nand_platform_data *pdata;
int err;
int i, offset;
+ dma_cap_mask_t mask;
+ unsigned sig;
pdata = pdev->dev.platform_data;
if (pdata == NULL) {
@@ -1244,6 +1302,33 @@ static int __devinit omap_nand_probe(struct platform_device *pdev)
break;
case NAND_OMAP_PREFETCH_DMA:
+ dma_cap_zero(mask);
+ dma_cap_set(DMA_SLAVE, mask);
+ sig = OMAP24XX_DMA_GPMC;
+ info->dma = dma_request_channel(mask, omap_dma_filter_fn, &sig);
+ if (!info->dma) {
+ dev_warn(&pdev->dev, "DMA engine request failed\n");
+ } else {
+ struct dma_slave_config cfg;
+ int rc;
+
+ memset(&cfg, 0, sizeof(cfg));
+ cfg.src_addr = info->phys_base;
+ cfg.dst_addr = info->phys_base;
+ cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+ cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+ cfg.src_maxburst = 16;
+ cfg.dst_maxburst = 16;
+ rc = dmaengine_slave_config(info->dma, &cfg);
+ if (rc) {
+ dev_err(&pdev->dev, "DMA engine slave config failed: %d\n",
+ rc);
+ goto out_release_mem_region;
+ }
+ info->nand.read_buf = omap_read_buf_dma_pref;
+ info->nand.write_buf = omap_write_buf_dma_pref;
+ break;
+ }
err = omap_request_dma(OMAP24XX_DMA_GPMC, "NAND",
omap_nand_dma_cb, &info->comp, &info->dma_ch);
if (err < 0) {
@@ -1358,6 +1443,8 @@ static int __devinit omap_nand_probe(struct platform_device *pdev)
return 0;
out_release_mem_region:
+ if (info->dma)
+ dma_release_channel(info->dma);
release_mem_region(info->phys_base, NAND_IO_SIZE);
out_free_info:
kfree(info);
@@ -1376,6 +1463,9 @@ static int omap_nand_remove(struct platform_device *pdev)
if (info->dma_ch != -1)
omap_free_dma(info->dma_ch);
+ if (info->dma)
+ dma_release_channel(info->dma);
+
if (info->gpmc_irq)
free_irq(info->gpmc_irq, info);
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