| Message ID | 20190209131500.29954-2-jagan@amarulasolutions.com |
|---|---|
| State | Changes Requested |
| Delegated to: | Jagannadha Sutradharudu Teki |
| Headers | show |
| Series | spi: Add Allwinner A31 SPI driver | expand |
On Sat, 9 Feb 2019 18:44:51 +0530 Jagan Teki <jagan@amarulasolutions.com> 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 <jagan@amarulasolutions.com> > --- > 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 <asm/arch/clock.h> > > +#include <linux/iopoll.h> > + > #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_XCH BIT(10) > #define SUN4I_CTL_CS_MASK 0x3000 > #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(&priv->regs->ctl); > writel(reg | SUN4I_CTL_XCH, &priv->regs->ctl); > > - /* Wait transfer to complete */ > - ret = wait_for_bit_le32(&priv->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(&priv->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;
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 <asm/arch/clock.h> +#include <linux/iopoll.h> + #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_XCH BIT(10) #define SUN4I_CTL_CS_MASK 0x3000 #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(&priv->regs->ctl); writel(reg | SUN4I_CTL_XCH, &priv->regs->ctl); - /* Wait transfer to complete */ - ret = wait_for_bit_le32(&priv->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(&priv->regs->ctl, 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;
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 <jagan@amarulasolutions.com> --- drivers/spi/sun4i_spi.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)