On 14/02/2019 08:36, Jagan Teki wrote:
> To drain rx fifo the fifo need to poll till the fifo
> count become empty.
Thanks for the changes!
Just realised, the description is somewhat misleading: We are not
waiting for the FIFO count to become empty, but actually for the RX FIFO
to fill up. Can you still change this, especially in the code comment below?
With that:
>
> The current code is using wait_for_bit logic on control
> register with exchange burst mode mask, which is not a
> proper way of waiting for draining fifo.
>
> So, add code for polling fifo status register till rxfifo
> count become empty.
>
> Signed-off-by: Jagan Teki
Reviewed-by: Andre Przywara
Cheers,
Andre.
> ---
> drivers/spi/sun4i_spi.c | 15 +--
> 1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/spi/sun4i_spi.c b/drivers/spi/sun4i_spi.c
> index 38cc743c61..f5f2d5635a 100644
> --- a/drivers/spi/sun4i_spi.c
> +++ b/drivers/spi/sun4i_spi.c
> @@ -31,6 +31,8 @@
>
> #include
>
> +#include
> +
> #define SUN4I_FIFO_DEPTH 64
>
> #define SUN4I_RXDATA_REG 0x00
> @@ -46,7 +48,6 @@
> #define SUN4I_CTL_LMTF BIT(6)
> #define SUN4I_CTL_TF_RST BIT(8)
> #define SUN4I_CTL_RF_RST BIT(9)
> -#define SUN4I_CTL_XCH_MASK 0x0400
> #define SUN4I_CTL_XCHBIT(10)
> #define SUN4I_CTL_CS_MASK0x3000
> #define SUN4I_CTL_CS(cs) (((cs) << 12) & SUN4I_CTL_CS_MASK)
> @@ -308,7 +309,7 @@ static int sun4i_spi_xfer(struct udevice *dev, unsigned
> int bitlen,
> struct dm_spi_slave_platdata *slave_plat = dev_get_parent_platdata(dev);
>
> u32 len = bitlen / 8;
> - u32 reg;
> + u32 reg, rx_fifocnt;
> u8 nbytes;
> int ret;
>
> @@ -343,10 +344,12 @@ static int sun4i_spi_xfer(struct udevice *dev, unsigned
> int bitlen,
> reg = readl(>regs->ctl);
> writel(reg | SUN4I_CTL_XCH, >regs->ctl);
>
> - /* Wait transfer to complete */
> - ret = wait_for_bit_le32(>regs->ctl, SUN4I_CTL_XCH_MASK,
> - false, SUN4I_SPI_TIMEOUT_US, false);
> - if (ret) {
> + /* Wait till RX FIFO to be empty */
> + ret = readl_poll_timeout(>regs->fifo_sta, rx_fifocnt,
> + (((rx_fifocnt &
> SUN4I_FIFO_STA_RF_CNT_MASK) >>
> + SUN4I_FIFO_STA_RF_CNT_BITS) >= nbytes),
> + SUN4I_SPI_TIMEOUT_US);
> + if (ret < 0) {
> printf("ERROR: sun4i_spi: Timeout transferring data\n");
> sun4i_spi_set_cs(bus, slave_plat->cs, false);
> return ret;
>
___
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