[U-Boot] [PATCH 1/1] arm: sunxi: Add NULL pointer check
Stefan Mavrodiev
stefan at olimex.com
Thu Dec 20 12:46:01 UTC 2018
On 12/20/18 2:44 PM, Jagan Teki wrote:
> On Thu, Dec 20, 2018 at 6:12 PM Stefan Mavrodiev <stefan at olimex.com> wrote:
>>
>> On 12/20/18 2:38 PM, Jagan Teki wrote:
>>> 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?
>> No idea. I can see it here:
>> https://patchwork.ozlabs.org/patch/1008181/
> OK, got it. I will format the commit and apply if are OK?
Sure. Thank you.
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