spi: cadence_qspi: support FIFO width other than 4 bytes

This patch makes the code compatible with FIFO depths other than 4
bytes. It also simplify read/write FIFO loops.

Signed-off-by: Vikas Manocha <vikas.manocha@st.com>
Tested-by: Stefan Roese <sr@denx.de>
Reviewed-by: Jagannadh Teki <jteki@openedev.com>

diff --git a/drivers/spi/cadence_qspi_apb.c b/drivers/spi/cadence_qspi_apb.c
index cbf0d42..d053407 100644 (file)
--- a/drivers/spi/cadence_qspi_apb.c
+++ b/drivers/spi/cadence_qspi_apb.c
@@ -200,18 +200,16 @@ static void cadence_qspi_apb_read_fifo_data(void *dest,
        unsigned int *dest_ptr = (unsigned int *)dest;
        unsigned int *src_ptr = (unsigned int *)src_ahb_addr;
 
-       while (remaining > 0) {
-               if (remaining >= CQSPI_FIFO_WIDTH) {
-                       *dest_ptr = readl(src_ptr);
-                       remaining -= CQSPI_FIFO_WIDTH;
-               } else {
-                       /* dangling bytes */
-                       temp = readl(src_ptr);
-                       memcpy(dest_ptr, &temp, remaining);
-                       break;
-               }
+       while (remaining >= sizeof(dest_ptr)) {
+               *dest_ptr = readl(src_ptr);
+               remaining -= sizeof(src_ptr);
                dest_ptr++;
        }
+       if (remaining) {
+               /* dangling bytes */
+               temp = readl(src_ptr);
+               memcpy(dest_ptr, &temp, remaining);
+       }
 
        return;
 }
@@ -219,24 +217,26 @@ static void cadence_qspi_apb_read_fifo_data(void *dest,
 static void cadence_qspi_apb_write_fifo_data(const void *dest_ahb_addr,
        const void *src, unsigned int bytes)
 {
-       unsigned int temp;
+       unsigned int temp = 0;
+       int i;
        int remaining = bytes;
        unsigned int *dest_ptr = (unsigned int *)dest_ahb_addr;
        unsigned int *src_ptr = (unsigned int *)src;
 
-       while (remaining > 0) {
-               if (remaining >= CQSPI_FIFO_WIDTH) {
-                       writel(*src_ptr, dest_ptr);
-                       remaining -= sizeof(unsigned int);
-               } else {
-                       /* dangling bytes */
-                       memcpy(&temp, src_ptr, remaining);
-                       writel(temp, dest_ptr);
-                       break;
-               }
-               src_ptr++;
+       while (remaining >= CQSPI_FIFO_WIDTH) {
+               for (i = CQSPI_FIFO_WIDTH/sizeof(src_ptr) - 1; i >= 0; i--)
+                       writel(*(src_ptr+i), dest_ptr+i);
+               src_ptr += CQSPI_FIFO_WIDTH/sizeof(src_ptr);
+               remaining -= CQSPI_FIFO_WIDTH;
+       }
+       if (remaining) {
+               /* dangling bytes */
+               i = remaining/sizeof(dest_ptr);
+               memcpy(&temp, src_ptr+i, remaining % sizeof(dest_ptr));
+               writel(temp, dest_ptr+i);
+               for (--i; i >= 0; i--)
+                       writel(*(src_ptr+i), dest_ptr+i);
        }
-
        return;
 }