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>

diff --git a/drivers/spi/spi-sh-msiof.c b/drivers/spi/spi-sh-msiof.c
index e5894a6..824f44e 100644 (file)
--- 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;
        }