[PATCH 2:2][MTD][NAND]omap : Adding DMA mode support in nand prefetch/post-write
vimal singh
vimalsingh at ti.com
Fri Jul 10 07:55:16 EDT 2009
This patch adds DMA mode support for nand prefetch/post-write engine.
Signed-off-by: Vimal Singh <vimalsingh at ti.com>
---
drivers/mtd/nand/Kconfig | 9 ++
drivers/mtd/nand/omap2.c | 186 ++++++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 193 insertions(+), 2 deletions(-)
Index: mtd-2.6/drivers/mtd/nand/Kconfig
===================================================================
--- mtd-2.6.orig/drivers/mtd/nand/Kconfig
+++ mtd-2.6/drivers/mtd/nand/Kconfig
@@ -88,6 +88,15 @@ config MTD_NAND_OMAP_PREFETCH
The NAND device can be accessed for Read/Write using GPMC PREFETCH engine
to improve the performance.
+config MTD_NAND_OMAP_PREFETCH_DMA
+ depends on MTD_NAND_OMAP_PREFETCH
+ bool "DMA mode"
+ default n
+ help
+ The GPMC PREFETCH engine can be configured eigther in MPU interrupt mode
+ or in DMA interrupt mode.
+ Say y for DMA mode or MPU mode will be used
+
config MTD_NAND_TS7250
tristate "NAND Flash device on TS-7250 board"
depends on MACH_TS72XX
Index: mtd-2.6/drivers/mtd/nand/omap2.c
===================================================================
--- mtd-2.6.orig/drivers/mtd/nand/omap2.c
+++ mtd-2.6/drivers/mtd/nand/omap2.c
@@ -18,8 +18,7 @@
#include <linux/mtd/partitions.h>
#include <linux/io.h>
-#include <asm/dma.h>
-
+#include <mach/dma.h>
#include <mach/gpmc.h>
#include <mach/nand.h>
@@ -118,8 +117,19 @@ static int use_prefetch = 1;
/* "modprobe ... use_prefetch=0" etc */
module_param(use_prefetch, bool, 0);
MODULE_PARM_DESC(use_prefetch, "enable/disable use of PREFETCH");
+
+#ifdef CONFIG_MTD_NAND_OMAP_PREFETCH_DMA
+static int use_dma = 1;
+
+/* "modprobe ... use_dma=0" etc */
+module_param(use_dma, bool, 0);
+MODULE_PARM_DESC(use_dma, "enable/disable use of DMA");
+#else
+const int use_dma;
+#endif
#else
const int use_prefetch;
+const int use_dma;
#endif
struct omap_nand_info {
@@ -135,6 +145,8 @@ struct omap_nand_info {
void __iomem *gpmc_cs_baseaddr;
void __iomem *gpmc_baseaddr;
void __iomem *nand_pref_fifo_add;
+ struct completion comp;
+ int dma_ch;
};
/**
@@ -356,6 +368,147 @@ static void omap_write_buf_pref(struct m
gpmc_prefetch_reset();
}
+#ifdef CONFIG_MTD_NAND_OMAP_PREFETCH_DMA
+/*
+ * omap_nand_dma_cb: callback on the completion of dma transfer
+ * @lch: logical channel
+ * @ch_satuts: channel status
+ * @data: pointer to completion data structure
+ */
+static void omap_nand_dma_cb(int lch, u16 ch_status, void *data)
+{
+ complete((struct completion *) data);
+}
+
+/*
+ * omap_nand_dma_transfer: configer and start dma transfer
+ * @mtd: MTD device structure
+ * @addr: virtual address in RAM of source/destination
+ * @len: number of data bytes to be transferred
+ * @is_write: flag for read/write operation
+ */
+static inline int omap_nand_dma_transfer(struct mtd_info *mtd, void *addr,
+ unsigned int len, int is_write)
+{
+ struct omap_nand_info *info = container_of(mtd,
+ struct omap_nand_info, mtd);
+ uint32_t prefetch_status = 0;
+ enum dma_data_direction dir = is_write ? DMA_TO_DEVICE :
+ DMA_FROM_DEVICE;
+ dma_addr_t dma_addr;
+ int ret;
+
+ /* The fifo depth is 64 bytes. We have a sync at each frame and frame
+ * length is 64 bytes.
+ */
+ int buf_len = len/64;
+
+ if (addr >= high_memory) {
+ struct page *p1;
+
+ if (((size_t)addr & PAGE_MASK) !=
+ ((size_t)(addr + len - 1) & PAGE_MASK))
+ goto out_copy;
+ p1 = vmalloc_to_page(addr);
+ if (!p1)
+ goto out_copy;
+ addr = page_address(p1) + ((size_t)addr & ~PAGE_MASK);
+ }
+
+ 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,
+ "Couldn't DMA map a %d byte buffer\n", len);
+ goto out_copy;
+ }
+
+ if (is_write) {
+ omap_set_dma_dest_params(info->dma_ch, 0, OMAP_DMA_AMODE_CONSTANT,
+ info->phys_base, 0, 0);
+ omap_set_dma_src_params(info->dma_ch, 0, OMAP_DMA_AMODE_POST_INC,
+ dma_addr, 0, 0);
+ omap_set_dma_transfer_params(info->dma_ch, OMAP_DMA_DATA_TYPE_S32,
+ 0x10, buf_len, OMAP_DMA_SYNC_FRAME,
+ OMAP24XX_DMA_GPMC, OMAP_DMA_DST_SYNC);
+ } else {
+ omap_set_dma_src_params(info->dma_ch, 0, OMAP_DMA_AMODE_CONSTANT,
+ info->phys_base, 0, 0);
+ omap_set_dma_dest_params(info->dma_ch, 0, OMAP_DMA_AMODE_POST_INC,
+ dma_addr, 0, 0);
+ omap_set_dma_transfer_params(info->dma_ch, OMAP_DMA_DATA_TYPE_S32,
+ 0x10, buf_len, OMAP_DMA_SYNC_FRAME,
+ OMAP24XX_DMA_GPMC, OMAP_DMA_SRC_SYNC);
+ }
+ /* configure and start prefetch transfer */
+ ret = gpmc_prefetch_enable(info->gpmc_cs, 0x1, len, is_write);
+ if (ret)
+ /* PFPW engine is busy, use cpu copy methode */
+ goto out_copy;
+
+ init_completion(&info->comp);
+
+ omap_start_dma(info->dma_ch);
+
+ /* setup and start DMA using dma_addr */
+ wait_for_completion(&info->comp);
+
+ while (0x3fff & (prefetch_status = gpmc_prefetch_status()))
+ ;
+ /* disable and stop the PFPW engine */
+ gpmc_prefetch_reset();
+
+ dma_unmap_single(&info->pdev->dev, dma_addr, len, dir);
+ return 0;
+
+out_copy:
+ if (info->nand.options & NAND_BUSWIDTH_16)
+ is_write == 0 ? omap_read_buf16(mtd, (u_char *) addr, len)
+ : omap_write_buf16(mtd, (u_char *) addr, len);
+ else
+ is_write == 0 ? omap_read_buf8(mtd, (u_char *) addr, len)
+ : omap_write_buf8(mtd, (u_char *) addr, len);
+ return 0;
+}
+#else
+static void omap_nand_dma_cb(int lch, u16 ch_status, void *data) {}
+static inline int omap_nand_dma_transfer(struct mtd_info *mtd, void *addr,
+ unsigned int len, int is_write)
+{
+ return 0;
+}
+#endif
+
+/**
+ * omap_read_buf_dma_pref - read data from NAND controller into buffer
+ * @mtd: MTD device structure
+ * @buf: buffer to store date
+ * @len: number of bytes to read
+ */
+static void omap_read_buf_dma_pref(struct mtd_info *mtd, u_char *buf, int len)
+{
+ if (len <= mtd->oobsize)
+ omap_read_buf_pref(mtd, buf, len);
+ else
+ /* start transfer in DMA mode */
+ omap_nand_dma_transfer(mtd, buf, len, 0x0);
+}
+
+/**
+ * omap_write_buf_dma_pref - write buffer to NAND controller
+ * @mtd: MTD device structure
+ * @buf: data buffer
+ * @len: number of bytes to write
+ */
+static void omap_write_buf_dma_pref(struct mtd_info *mtd,
+ const u_char *buf, int len)
+{
+ if (len <= mtd->oobsize)
+ omap_write_buf_pref(mtd, buf, len);
+ else
+ /* start transfer in DMA mode */
+ omap_nand_dma_transfer(mtd, buf, len, 0x1);
+}
+
/**
* omap_verify_buf - Verify chip data against buffer
* @mtd: MTD device structure
@@ -822,6 +975,23 @@ static int __devinit omap_nand_probe(str
info->nand.read_buf = omap_read_buf_pref;
info->nand.write_buf = omap_write_buf_pref;
+ if (use_dma) {
+ err = omap_request_dma(OMAP24XX_DMA_GPMC, "NAND",
+ omap_nand_dma_cb, &info->comp, &info->dma_ch);
+ if (err < 0) {
+ info->dma_ch = -1;
+ printk(KERN_WARNING "DMA request failed."
+ " Non-dma data transfer mode\n");
+ } else {
+ omap_set_dma_dest_burst_mode(info->dma_ch,
+ OMAP_DMA_DATA_BURST_16);
+ omap_set_dma_src_burst_mode(info->dma_ch,
+ OMAP_DMA_DATA_BURST_16);
+
+ info->nand.read_buf = omap_read_buf_dma_pref;
+ info->nand.write_buf = omap_write_buf_dma_pref;
+ }
+ }
} else {
if (info->nand.options & NAND_BUSWIDTH_16) {
info->nand.read_buf = omap_read_buf16;
@@ -888,6 +1058,9 @@ static int omap_nand_remove(struct platf
struct omap_nand_info *info = mtd->priv;
platform_set_drvdata(pdev, NULL);
+ if (use_dma)
+ omap_free_dma(info->dma_ch);
+
/* Release NAND device, its internal structures and partitions */
nand_release(&info->mtd);
iounmap(info->nand_pref_fifo_add);
@@ -907,6 +1080,15 @@ static struct platform_driver omap_nand_
static int __init omap_nand_init(void)
{
printk(KERN_INFO "%s driver initializing\n", DRIVER_NAME);
+
+ /* This check is required if driver is being
+ * loaded run time as a module
+ */
+ if ((1 == use_dma) && (0 == use_prefetch)) {
+ printk(KERN_INFO"Wrong parameters: 'use_dma' can not be 1 "
+ "without use_prefetch'. Prefetch will not be"
+ " used in either mode (mpu or dma)\n");
+ }
return platform_driver_register(&omap_nand_driver);
}
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