On Thu, Jan 25, 2024 at 8:50 AM Tudor Ambarus <tudor.ambarus@xxxxxxxxxx> wrote:
>
> s3c64xx_spi_transfer_one() makes sure that for PIO the xfer->len is
> always smaller than the fifo size. Since we can't receive more that the
> FIFO size, droop the loop handling, the code becomes less misleading.
Drop (spelling)?
For the patch: how exactly it was tested to make sure there is no regression?
>
> Signed-off-by: Tudor Ambarus <tudor.ambarus@xxxxxxxxxx>
> ---
> drivers/spi/spi-s3c64xx.c | 75 +++++++++------------------------------
> 1 file changed, 17 insertions(+), 58 deletions(-)
>
> diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
> index d2dd28ff00c6..00a0878aeb80 100644
> --- a/drivers/spi/spi-s3c64xx.c
> +++ b/drivers/spi/spi-s3c64xx.c
> @@ -485,26 +485,6 @@ static int s3c64xx_enable_datapath(struct s3c64xx_spi_driver_data *sdd,
> return 0;
> }
>
> -static u32 s3c64xx_spi_wait_for_timeout(struct s3c64xx_spi_driver_data *sdd,
> - int timeout_ms)
> -{
> - void __iomem *regs = sdd->regs;
> - unsigned long val = 1;
> - u32 status;
> - u32 max_fifo = FIFO_DEPTH(sdd);
> -
> - if (timeout_ms)
> - val = msecs_to_loops(timeout_ms);
> -
> - do {
> - status = readl(regs + S3C64XX_SPI_STATUS);
> - } while (FIELD_GET(S3C64XX_SPI_ST_RX_FIFO_LVL, status) < max_fifo &&
> - --val);
> -
> - /* return the actual received data length */
> - return FIELD_GET(S3C64XX_SPI_ST_RX_FIFO_LVL, status);
> -}
> -
> static int s3c64xx_wait_for_dma(struct s3c64xx_spi_driver_data *sdd,
> struct spi_transfer *xfer)
> {
> @@ -553,13 +533,11 @@ static int s3c64xx_wait_for_pio(struct s3c64xx_spi_driver_data *sdd,
> struct spi_transfer *xfer, bool use_irq)
> {
> void __iomem *regs = sdd->regs;
> + u8 *buf = xfer->rx_buf;
> + unsigned long time_us;
> unsigned long val;
> - u32 status;
> - int loops;
> - u32 cpy_len;
> - u8 *buf;
> + u32 status, len;
> int ms;
> - unsigned long time_us;
>
> /* microsecs to xfer 'len' bytes @ 'cur_speed' */
> time_us = (xfer->len * 8 * 1000 * 1000) / sdd->cur_speed;
> @@ -582,48 +560,29 @@ static int s3c64xx_wait_for_pio(struct s3c64xx_spi_driver_data *sdd,
> status = readl(regs + S3C64XX_SPI_STATUS);
> } while (FIELD_GET(S3C64XX_SPI_ST_RX_FIFO_LVL, status) < xfer->len &&
> --val);
> -
> if (!val)
> return -EIO;
>
> /* If it was only Tx */
> - if (!xfer->rx_buf) {
> + if (!buf) {
> sdd->state &= ~TXBUSY;
> return 0;
> }
>
> - /*
> - * If the receive length is bigger than the controller fifo
> - * size, calculate the loops and read the fifo as many times.
> - * loops = length / max fifo size (calculated by using the
> - * fifo mask).
> - * For any size less than the fifo size the below code is
> - * executed atleast once.
> - */
> - loops = xfer->len / FIFO_DEPTH(sdd);
> - buf = xfer->rx_buf;
> - do {
> - /* wait for data to be received in the fifo */
> - cpy_len = s3c64xx_spi_wait_for_timeout(sdd,
> - (loops ? ms : 0));
> -
> - switch (sdd->cur_bpw) {
> - case 32:
> - ioread32_rep(regs + S3C64XX_SPI_RX_DATA,
> - buf, cpy_len / 4);
> - break;
> - case 16:
> - ioread16_rep(regs + S3C64XX_SPI_RX_DATA,
> - buf, cpy_len / 2);
> - break;
> - default:
> - ioread8_rep(regs + S3C64XX_SPI_RX_DATA,
> - buf, cpy_len);
> - break;
> - }
> + len = FIELD_GET(S3C64XX_SPI_ST_RX_FIFO_LVL, status);
> +
> + switch (sdd->cur_bpw) {
> + case 32:
> + ioread32_rep(regs + S3C64XX_SPI_RX_DATA, buf, len / 4);
> + break;
> + case 16:
> + ioread16_rep(regs + S3C64XX_SPI_RX_DATA, buf, len / 2);
> + break;
> + default:
> + ioread8_rep(regs + S3C64XX_SPI_RX_DATA, buf, len);
> + break;
> + }
>
> - buf = buf + cpy_len;
> - } while (loops--);
> sdd->state &= ~RXBUSY;
>
> return 0;
> --
> 2.43.0.429.g432eaa2c6b-goog
>
