mtd: omap: add support for nand prefetch-read and post-write
This patch adds prefetch support to access nand flash in mpu mode.
This patch also adds 8-bit nand support (omap_read/write_buf8).
Prefetch can be used for both 8- and 16-bit devices.
Signed-off-by: Vimal Singh <vimalsingh@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index ebd07e9..6736822 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -112,6 +112,16 @@
static const char *part_probes[] = { "cmdlinepart", NULL };
#endif
+#ifdef CONFIG_MTD_NAND_OMAP_PREFETCH
+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");
+#else
+const int use_prefetch;
+#endif
+
struct omap_nand_info {
struct nand_hw_control controller;
struct omap_nand_platform_data *pdata;
@@ -124,6 +134,7 @@
unsigned long phys_base;
void __iomem *gpmc_cs_baseaddr;
void __iomem *gpmc_baseaddr;
+ void __iomem *nand_pref_fifo_add;
};
/**
@@ -189,6 +200,38 @@
}
/**
+ * omap_read_buf8 - 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_buf8(struct mtd_info *mtd, u_char *buf, int len)
+{
+ struct nand_chip *nand = mtd->priv;
+
+ ioread8_rep(nand->IO_ADDR_R, buf, len);
+}
+
+/**
+ * omap_write_buf8 - write buffer to NAND controller
+ * @mtd: MTD device structure
+ * @buf: data buffer
+ * @len: number of bytes to write
+ */
+static void omap_write_buf8(struct mtd_info *mtd, const u_char *buf, int len)
+{
+ struct omap_nand_info *info = container_of(mtd,
+ struct omap_nand_info, mtd);
+ u_char *p = (u_char *)buf;
+
+ while (len--) {
+ iowrite8(*p++, info->nand.IO_ADDR_W);
+ while (GPMC_BUF_EMPTY == (readl(info->gpmc_baseaddr +
+ GPMC_STATUS) & GPMC_BUF_FULL));
+ }
+}
+
+/**
* omap_read_buf16 - read data from NAND controller into buffer
* @mtd: MTD device structure
* @buf: buffer to store date
@@ -198,7 +241,7 @@
{
struct nand_chip *nand = mtd->priv;
- __raw_readsw(nand->IO_ADDR_R, buf, len / 2);
+ ioread16_rep(nand->IO_ADDR_R, buf, len / 2);
}
/**
@@ -217,13 +260,101 @@
len >>= 1;
while (len--) {
- writew(*p++, info->nand.IO_ADDR_W);
+ iowrite16(*p++, info->nand.IO_ADDR_W);
while (GPMC_BUF_EMPTY == (readl(info->gpmc_baseaddr +
GPMC_STATUS) & GPMC_BUF_FULL))
;
}
}
+
+/**
+ * omap_read_buf_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_pref(struct mtd_info *mtd, u_char *buf, int len)
+{
+ struct omap_nand_info *info = container_of(mtd,
+ struct omap_nand_info, mtd);
+ uint32_t pfpw_status = 0, r_count = 0;
+ int ret = 0;
+ u32 *p = (u32 *)buf;
+
+ /* take care of subpage reads */
+ for (; len % 4 != 0; ) {
+ *buf++ = __raw_readb(info->nand.IO_ADDR_R);
+ len--;
+ }
+ p = (u32 *) buf;
+
+ /* configure and start prefetch transfer */
+ ret = gpmc_prefetch_enable(info->gpmc_cs, 0x0, len, 0x0);
+ if (ret) {
+ /* PFPW engine is busy, use cpu copy method */
+ if (info->nand.options & NAND_BUSWIDTH_16)
+ omap_read_buf16(mtd, buf, len);
+ else
+ omap_read_buf8(mtd, buf, len);
+ } else {
+ do {
+ pfpw_status = gpmc_prefetch_status();
+ r_count = ((pfpw_status >> 24) & 0x7F) >> 2;
+ ioread32_rep(info->nand_pref_fifo_add, p, r_count);
+ p += r_count;
+ len -= r_count << 2;
+ } while (len);
+
+ /* disable and stop the PFPW engine */
+ gpmc_prefetch_reset();
+ }
+}
+
+/**
+ * omap_write_buf_pref - write buffer to NAND controller
+ * @mtd: MTD device structure
+ * @buf: data buffer
+ * @len: number of bytes to write
+ */
+static void omap_write_buf_pref(struct mtd_info *mtd,
+ const u_char *buf, int len)
+{
+ struct omap_nand_info *info = container_of(mtd,
+ struct omap_nand_info, mtd);
+ uint32_t pfpw_status = 0, w_count = 0;
+ int i = 0, ret = 0;
+ u16 *p = (u16 *) buf;
+
+ /* take care of subpage writes */
+ if (len % 2 != 0) {
+ writeb(*buf, info->nand.IO_ADDR_R);
+ p = (u16 *)(buf + 1);
+ len--;
+ }
+
+ /* configure and start prefetch transfer */
+ ret = gpmc_prefetch_enable(info->gpmc_cs, 0x0, len, 0x1);
+ if (ret) {
+ /* PFPW engine is busy, use cpu copy method */
+ if (info->nand.options & NAND_BUSWIDTH_16)
+ omap_write_buf16(mtd, buf, len);
+ else
+ omap_write_buf8(mtd, buf, len);
+ } else {
+ pfpw_status = gpmc_prefetch_status();
+ while (pfpw_status & 0x3FFF) {
+ w_count = ((pfpw_status >> 24) & 0x7F) >> 1;
+ for (i = 0; (i < w_count) && len; i++, len -= 2)
+ iowrite16(*p++, info->nand_pref_fifo_add);
+ pfpw_status = gpmc_prefetch_status();
+ }
+
+ /* disable and stop the PFPW engine */
+ gpmc_prefetch_reset();
+ }
+}
+
/**
* omap_verify_buf - Verify chip data against buffer
* @mtd: MTD device structure
@@ -658,17 +789,12 @@
err = -ENOMEM;
goto out_release_mem_region;
}
+
info->nand.controller = &info->controller;
info->nand.IO_ADDR_W = info->nand.IO_ADDR_R;
info->nand.cmd_ctrl = omap_hwcontrol;
- /* REVISIT: only supports 16-bit NAND flash */
-
- info->nand.read_buf = omap_read_buf16;
- info->nand.write_buf = omap_write_buf16;
- info->nand.verify_buf = omap_verify_buf;
-
/*
* If RDY/BSY line is connected to OMAP then use the omap ready
* funcrtion and the generic nand_wait function which reads the status
@@ -689,6 +815,23 @@
== 0x1000)
info->nand.options |= NAND_BUSWIDTH_16;
+ if (use_prefetch) {
+ /* copy the virtual address of nand base for fifo access */
+ info->nand_pref_fifo_add = info->nand.IO_ADDR_R;
+
+ info->nand.read_buf = omap_read_buf_pref;
+ info->nand.write_buf = omap_write_buf_pref;
+ } else {
+ if (info->nand.options & NAND_BUSWIDTH_16) {
+ info->nand.read_buf = omap_read_buf16;
+ info->nand.write_buf = omap_write_buf16;
+ } else {
+ info->nand.read_buf = omap_read_buf8;
+ info->nand.write_buf = omap_write_buf8;
+ }
+ }
+ info->nand.verify_buf = omap_verify_buf;
+
#ifdef CONFIG_MTD_NAND_OMAP_HWECC
info->nand.ecc.bytes = 3;
info->nand.ecc.size = 512;
@@ -746,7 +889,7 @@
platform_set_drvdata(pdev, NULL);
/* Release NAND device, its internal structures and partitions */
nand_release(&info->mtd);
- iounmap(info->nand.IO_ADDR_R);
+ iounmap(info->nand_pref_fifo_add);
kfree(&info->mtd);
return 0;
}