On Sat, 9 Feb 2019 18:44:51 +0530
Jagan Teki wrote:
Hi,
> To drain rx fifo the fifo need to poll till the fifo
> count become empty.
>
> 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
> ---
> 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..87b396a96e 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->ctl, rx_fifocnt,
That's not the right register, it should be regs->fifo_sta.
> + !(((rx_fifocnt &
> SUN4I_FIFO_STA_RF_CNT_MASK) >>
> + SUN4I_FIFO_STA_RF_CNT_BITS) < nbytes),
I think removing the negation and using ">=" instead is less confusing.
Cheers,
Andre.
> + 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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