mtd: rawnand: omap_gpmc: Optimize NAND reads

Rename omap_nand_read() to omap_nand_read_buf() to reflect
actual behaviour.

Use FIFO read address instead of raw read address for reads.

The GPMC automatically converts 32-bit/16-bit reads to NAND
device specific reads (8/16 bit). Use the largest possible
read granularity size for more efficient reads.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
Reviewed-by: Michael Trimarchi <michael@amarulasolutions.com>
Link: https://lore.kernel.org/all/20221011115012.6181-5-rogerq@kernel.org
Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>

diff --git a/drivers/mtd/nand/raw/omap_gpmc.c b/drivers/mtd/nand/raw/omap_gpmc.c
index d62c3e6..b36fe76 100644 (file)
--- a/drivers/mtd/nand/raw/omap_gpmc.c
+++ b/drivers/mtd/nand/raw/omap_gpmc.c
@@ -55,6 +55,7 @@ struct omap_nand_info {
        enum omap_ecc ecc_scheme;
        uint8_t cs;
        uint8_t ws;             /* wait status pin (0,1) */
+       void __iomem *fifo;
 };
 
 /* We are wasting a bit of memory but al least we are safe */
@@ -350,6 +351,20 @@ static int omap_calculate_ecc(struct mtd_info *mtd, const uint8_t *dat,
        return 0;
 }
 
+static inline void omap_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
+{
+       struct nand_chip *chip = mtd_to_nand(mtd);
+       struct omap_nand_info *info = nand_get_controller_data(chip);
+       u32 alignment = ((uintptr_t)buf | len) & 3;
+
+       if (alignment & 1)
+               readsb(info->fifo, buf, len);
+       else if (alignment & 3)
+               readsw(info->fifo, buf, len >> 1);
+       else
+               readsl(info->fifo, buf, len >> 2);
+}
+
 #ifdef CONFIG_NAND_OMAP_GPMC_PREFETCH
 
 #define PREFETCH_CONFIG1_CS_SHIFT      24
@@ -415,7 +430,7 @@ static int __read_prefetch_aligned(struct nand_chip *chip, uint32_t *buf, int le
                cnt = PREFETCH_STATUS_FIFO_CNT(cnt);
 
                for (i = 0; i < cnt / 4; i++) {
-                       *buf++ = readl(CONFIG_SYS_NAND_BASE);
+                       *buf++ = readl(info->fifo);
                        len -= 4;
                }
        } while (len);
@@ -425,16 +440,6 @@ static int __read_prefetch_aligned(struct nand_chip *chip, uint32_t *buf, int le
        return 0;
 }
 
-static inline void omap_nand_read(struct mtd_info *mtd, uint8_t *buf, int len)
-{
-       struct nand_chip *chip = mtd_to_nand(mtd);
-
-       if (chip->options & NAND_BUSWIDTH_16)
-               nand_read_buf16(mtd, buf, len);
-       else
-               nand_read_buf(mtd, buf, len);
-}
-
 static void omap_nand_read_prefetch(struct mtd_info *mtd, uint8_t *buf, int len)
 {
        int ret;
@@ -447,7 +452,7 @@ static void omap_nand_read_prefetch(struct mtd_info *mtd, uint8_t *buf, int len)
         */
        head = ((uintptr_t)buf) % 4;
        if (head) {
-               omap_nand_read(mtd, buf, head);
+               omap_nand_read_buf(mtd, buf, head);
                buf += head;
                len -= head;
        }
@@ -461,10 +466,10 @@ static void omap_nand_read_prefetch(struct mtd_info *mtd, uint8_t *buf, int len)
        ret = __read_prefetch_aligned(chip, (uint32_t *)buf, len - tail);
        if (ret < 0) {
                /* fallback in case the prefetch engine is busy */
-               omap_nand_read(mtd, buf, len);
+               omap_nand_read_buf(mtd, buf, len);
        } else if (tail) {
                buf += len - tail;
-               omap_nand_read(mtd, buf, tail);
+               omap_nand_read_buf(mtd, buf, tail);
        }
 }
 #endif /* CONFIG_NAND_OMAP_GPMC_PREFETCH */
@@ -1001,6 +1006,8 @@ int board_nand_init(struct nand_chip *nand)
        int32_t gpmc_config = 0;
        int cs = cs_next++;
        int err = 0;
+       struct omap_nand_info *info;
+
        /*
         * xloader/Uboot's gpmc configuration would have configured GPMC for
         * nand type of memory. The following logic scans and latches on to the
@@ -1029,9 +1036,12 @@ int board_nand_init(struct nand_chip *nand)
 
        nand->IO_ADDR_R = (void __iomem *)&gpmc_cfg->cs[cs].nand_dat;
        nand->IO_ADDR_W = (void __iomem *)&gpmc_cfg->cs[cs].nand_cmd;
-       omap_nand_info[cs].control = NULL;
-       omap_nand_info[cs].cs = cs;
-       omap_nand_info[cs].ws = wscfg[cs];
+
+       info = &omap_nand_info[cs];
+       info->control = NULL;
+       info->cs = cs;
+       info->ws = wscfg[cs];
+       info->fifo = (void __iomem *)CONFIG_SYS_NAND_BASE;
        nand_set_controller_data(nand, &omap_nand_info[cs]);
        nand->cmd_ctrl  = omap_nand_hwcontrol;
        nand->options   |= NAND_NO_PADDING | NAND_CACHEPRG;
@@ -1062,10 +1072,7 @@ int board_nand_init(struct nand_chip *nand)
 #ifdef CONFIG_NAND_OMAP_GPMC_PREFETCH
        nand->read_buf = omap_nand_read_prefetch;
 #else
-       if (nand->options & NAND_BUSWIDTH_16)
-               nand->read_buf = nand_read_buf16;
-       else
-               nand->read_buf = nand_read_buf;
+       nand->read_buf = omap_nand_read_buf;
 #endif
 
        nand->dev_ready = omap_dev_ready;