spi: sh-msiof: Refactor sh_msiof_transfer_one()

  - Move buffer pointer and length setup to the top,
  - Make unsigned values unsigned,
  - Loop over words and increment pointers instead of recalculating them,
    which allows to kill bytes_done.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@linaro.org>

1 files changed, 21 insertions, 22 deletions

diff --git a/drivers/spi/spi-sh-msiof.c b/drivers/spi/spi-sh-msiof.c
index e5894a65c797..824f44e6bd88 100644
--- a/drivers/spi/spi-sh-msiof.c
+++ b/drivers/spi/spi-sh-msiof.c
@@ -616,16 +616,17 @@ static int sh_msiof_transfer_one(struct spi_master *master,
         struct sh_msiof_spi_priv *p = spi_master_get_devdata(master);
         void (*tx_fifo)(struct sh_msiof_spi_priv *, const void *, int, int);
         void (*rx_fifo)(struct sh_msiof_spi_priv *, void *, int, int);
-        int bits;
-        int bytes_per_word;
-        int bytes_done;
-        int words;
+        const void *tx_buf = t->tx_buf;
+        void *rx_buf = t->rx_buf;
+        unsigned int len = t->len;
+        unsigned int bits = t->bits_per_word;
+        unsigned int bytes_per_word;
+        unsigned int words;
         int n;
         bool swab;
 
-        bits = t->bits_per_word;
 
-        if (bits <= 8 && t->len > 15 && !(t->len & 3)) {
+        if (bits <= 8 && len > 15 && !(len & 3)) {
                 bits = 32;
                 swab = true;
         } else {
@@ -639,34 +640,34 @@ static int sh_msiof_transfer_one(struct spi_master *master,
                 rx_fifo = sh_msiof_spi_read_fifo_8;
         } else if (bits <= 16) {
                 bytes_per_word = 2;
-                if ((unsigned long)t->tx_buf & 0x01)
+                if ((unsigned long)tx_buf & 0x01)
                         tx_fifo = sh_msiof_spi_write_fifo_16u;
                 else
                         tx_fifo = sh_msiof_spi_write_fifo_16;
 
-                if ((unsigned long)t->rx_buf & 0x01)
+                if ((unsigned long)rx_buf & 0x01)
                         rx_fifo = sh_msiof_spi_read_fifo_16u;
                 else
                         rx_fifo = sh_msiof_spi_read_fifo_16;
         } else if (swab) {
                 bytes_per_word = 4;
-                if ((unsigned long)t->tx_buf & 0x03)
+                if ((unsigned long)tx_buf & 0x03)
                         tx_fifo = sh_msiof_spi_write_fifo_s32u;
                 else
                         tx_fifo = sh_msiof_spi_write_fifo_s32;
 
-                if ((unsigned long)t->rx_buf & 0x03)
+                if ((unsigned long)rx_buf & 0x03)
                         rx_fifo = sh_msiof_spi_read_fifo_s32u;
                 else
                         rx_fifo = sh_msiof_spi_read_fifo_s32;
         } else {
                 bytes_per_word = 4;
-                if ((unsigned long)t->tx_buf & 0x03)
+                if ((unsigned long)tx_buf & 0x03)
                         tx_fifo = sh_msiof_spi_write_fifo_32u;
                 else
                         tx_fifo = sh_msiof_spi_write_fifo_32;
 
-                if ((unsigned long)t->rx_buf & 0x03)
+                if ((unsigned long)rx_buf & 0x03)
                         rx_fifo = sh_msiof_spi_read_fifo_32u;
                 else
                         rx_fifo = sh_msiof_spi_read_fifo_32;
@@ -676,20 +677,18 @@ static int sh_msiof_transfer_one(struct spi_master *master,
         sh_msiof_spi_set_clk_regs(p, clk_get_rate(p->clk), t->speed_hz);
 
         /* transfer in fifo sized chunks */
-        words = t->len / bytes_per_word;
-        bytes_done = 0;
-
-        while (bytes_done < t->len) {
-                void *rx_buf = t->rx_buf ? t->rx_buf + bytes_done : NULL;
-                const void *tx_buf = t->tx_buf ? t->tx_buf + bytes_done : NULL;
-                n = sh_msiof_spi_txrx_once(p, tx_fifo, rx_fifo,
-                                           tx_buf,
-                                           rx_buf,
+        words = len / bytes_per_word;
+
+        while (words > 0) {
+                n = sh_msiof_spi_txrx_once(p, tx_fifo, rx_fifo, tx_buf, rx_buf,
                                            words, bits);
                 if (n < 0)
                         return n;
 
-                bytes_done += n * bytes_per_word;
+                if (tx_buf)
+                        tx_buf += n * bytes_per_word;
+                if (rx_buf)
+                        rx_buf += n * bytes_per_word;
                 words -= n;
         }