[U-Boot] [PATCH 1/1] arm: sunxi: Add NULL pointer check

Jagan Teki jagan at amarulasolutions.com
Thu Dec 20 12:38:23 UTC 2018


On Thu, Dec 20, 2018 at 5:38 PM Stefan Mavrodiev <stefan at olimex.com> wrote:
>
>
> On 12/20/18 1:54 PM, Jagan Teki wrote:
> > On Thu, Dec 20, 2018 at 4:49 PM Stefan Mavrodiev <stefan at olimex.com> wrote:
> >>
> >> On 12/20/18 12:56 PM, Jagan Teki wrote:
> >>> On Thu, Dec 20, 2018 at 4:18 PM Stefan Mavrodiev <stefan at olimex.com> wrote:
> >>>> On 12/20/18 12:45 PM, Jagan Teki wrote:
> >>>>> On Thu, Dec 20, 2018 at 3:59 PM Stefan Mavrodiev <stefan at olimex.com> wrote:
> >>>>>> On 12/20/18 12:14 PM, Jagan Teki wrote:
> >>>>>>> On Fri, Dec 14, 2018 at 3:48 PM Jagan Teki <jagan at amarulasolutions.com> wrote:
> >>>>>>>> On Wed, Dec 5, 2018 at 5:58 PM Stefan Mavrodiev <stefan at olimex.com> wrote:
> >>>>>>>>> Current driver doesn't check if the destination pointer is NULL.
> >>>>>>>>> This cause the data from the FIFO to be stored inside the internal
> >>>>>>>>> SDRAM ( address 0 ).
> >>>>>>>>>
> >>>>>>>>> The patch add simple check if the destination pointer is NULL.
> >>>>>>>>>
> >>>>>>>>> Signed-off-by: Stefan Mavrodiev <stefan at olimex.com>
> >>>>>>>>> ---
> >>>>>>>>>      drivers/spi/sun4i_spi.c | 3 ++-
> >>>>>>>>>      1 file changed, 2 insertions(+), 1 deletion(-)
> >>>>>>>>>
> >>>>>>>>> diff --git a/drivers/spi/sun4i_spi.c b/drivers/spi/sun4i_spi.c
> >>>>>>>>> index b86b5a00ad..38cc743c61 100644
> >>>>>>>>> --- a/drivers/spi/sun4i_spi.c
> >>>>>>>>> +++ b/drivers/spi/sun4i_spi.c
> >>>>>>>>> @@ -129,7 +129,8 @@ static inline void sun4i_spi_drain_fifo(struct sun4i_spi_priv *priv, int len)
> >>>>>>>>>
> >>>>>>>>>             while (len--) {
> >>>>>>>>>                     byte = readb(&priv->regs->rxdata);
> >>>>>>>>> -               *priv->rx_buf++ = byte;
> >>>>>>>>> +               if (priv->rx_buf)
> >>>>>>>>> +                       *priv->rx_buf++ = byte;
> >>>>>>>> Acked-by: Jagan Teki <jagan at openedev.com>
> >>>>>>>>
> >>>>>>>> But, have you tested how much data in the fifo before drained? It's
> >>>>>>>> better we can get the available data before reading via fifo_sta
> >>>>>> I don't understand what's the point of doing this?
> >>>>> Didn't get? don't you understand what I'm saying or it not require
> >>>>> from point of you?
> >>>> Maybe I don't understand correctly what you're saying.
> >>> You comment now and previous mail doesn't match. better be specific.
> >>>
> >>> For draining fifo.
> >>> We can find how much data available before reading from fifo and
> >>> assign to local rx.
> >>>
> >>> static inline void sun4i_spi_drain_fifo(struct sun4i_spi_priv *priv, int len)
> >>> {
> >>>          u32 reg, cnt
> >>>          u8 byte;
> >>>
> >>>           /* See how much data is available */
> >>>           reg = readl(&priv->regs->fifo_sta);
> >>>           reg &= SUN4I_FIFO_STA_RF_CNT_MASK;
> >>>           cnt = reg >> SUN4I_FIFO_STA_RF_CNT_BITS;
> >>>
> >>>           if (len > cnt)
> >>>                   len = cnt;
> >>>
> >>>           while (len--) {
> >>>                   byte = readb(&priv->regs->rxdata);
> >>>                   *priv->rx_buf++ = byte;
> >>>           }
> >>> }
> >>>
> >>> This can be perfect drain fifo, and this is what I'm trying to test
> >>> you with existing code and after your patch and verify whether all the
> >>> data perfectly drain or not before and after.
> >>>
> >>> Hope you understand, this time.
> >>
> >> Hope I understood this time...
> >>
> >>
> >> I've made some modification to sun4i_spi_xfer:
> >>
> >> static int sun4i_spi_xfer(struct udevice *dev, unsigned int bitlen,
> >>                 const void *dout, void *din, unsigned long flags)
> >> {
> >>       struct udevice *bus = dev->parent;
> >>       struct sun4i_spi_priv *priv = dev_get_priv(bus);
> >>       struct dm_spi_slave_platdata *slave_plat =
> >> dev_get_parent_platdata(dev);
> >>
> >>       u32 len = bitlen / 8;
> >>       u32 reg, cnt;
> >>       u8 nbytes;
> >>       int ret;
> >>
> >>       priv->tx_buf = dout;
> >>       priv->rx_buf = din;
> >>
> >>       if (bitlen % 8) {
> >>           debug("%s: non byte-aligned SPI transfer.\n", __func__);
> >>           return -ENAVAIL;
> >>       }
> >>
> >>       if (flags & SPI_XFER_BEGIN)
> >>           sun4i_spi_set_cs(bus, slave_plat->cs, true);
> >>
> >>       reg = readl(&priv->regs->ctl);
> >>
> >>       /* Reset FIFOs */
> >>       writel(reg | SUN4I_CTL_RF_RST | SUN4I_CTL_TF_RST, &priv->regs->ctl);
> >>
> >>       while (len) {
> >>           /* Setup the transfer now... */
> >>           nbytes = min(len, (u32)(SUN4I_FIFO_DEPTH - 1));
> >>
> >>           if (!priv->rx_buf)
> >>               printf("%s: Sending %d bytes, ", __func__, nbytes);
> >>
> >>           /* Setup the counters */
> >>           writel(SUN4I_BURST_CNT(nbytes), &priv->regs->bc);
> >>           writel(SUN4I_XMIT_CNT(nbytes), &priv->regs->tc);
> >>
> >>           /* Fill the TX FIFO */
> >>           sun4i_spi_fill_fifo(priv, nbytes);
> >>
> >>           /* Start the transfer */
> >>           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) {
> >>               printf("ERROR: sun4i_spi: Timeout transferring data\n");
> >>               sun4i_spi_set_cs(bus, slave_plat->cs, false);
> >>               return ret;
> >>           }
> >>
> >>           /* Drain the RX FIFO */
> >>           if (!priv->rx_buf) {
> >>               reg = readl(&priv->regs->fifo_sta);
> >>               reg &= SUN4I_FIFO_STA_RF_CNT_MASK;
> >>               cnt = reg >> SUN4I_FIFO_STA_RF_CNT_BITS;
> >>               printf("rx fifo: before: %d, ", cnt);
> >>           }
> >>
> >>           sun4i_spi_drain_fifo(priv, nbytes);
> > So it's draining fifo without need to checking the available count
> > insun4i_spi_drain_fifo(), I mean the below code not require.
> >
> >          /* See how much data is available */
> >          reg = readl(&priv->regs->fifo_sta);
> >          reg &= SUN4I_FIFO_STA_RF_CNT_MASK;
> >          cnt = reg >> SUN4I_FIFO_STA_RF_CNT_BITS;
> >
> >          if (len > cnt)
> >                  len = cnt;
>
> Yes, I didn't made any modification to sun4i_spi_drain_fifo() function:

OK, thanks for the details and test.

Please send the v2 with proper commit head it should be "spi: sun4i:  ..."
Also I didn't find this patch on patchwork, don't know why?


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