diff mbox series

[wireless-next,v2,1/4] wifi: rtw88: sdio: Check the HISR RX_REQUEST bit in rtw_sdio_rx_isr()

Message ID 20230522202425.1827005-2-martin.blumenstingl@googlemail.com (mailing list archive)
State New, archived
Headers show
Series wifi: rtw88: Add support for the RTL8723DS SDIO wifi chip | expand

Commit Message

Martin Blumenstingl May 22, 2023, 8:24 p.m. UTC 
rtw_sdio_rx_isr() is responsible for receiving data from the wifi chip
and is called from the SDIO interrupt handler when the interrupt status
register (HISR) has the RX_REQUEST bit set. After the first batch of
data has been processed by the driver the wifi chip may have more data
ready to be read, which is managed by a loop in rtw_sdio_rx_isr().

It turns out that there are cases where the RX buffer length (from the
REG_SDIO_RX0_REQ_LEN register) does not match the data we receive. The
following two cases were observed with a RTL8723DS card:
- RX length is smaller than the total packet length including overhead
  and actual data bytes (whose length is part of the buffer we read from
  the wifi chip and is stored in rtw_rx_pkt_stat.pkt_len). This can
  result in errors like:
    skbuff: skb_over_panic: text:ffff8000011924ac len:3341 put:3341
  (one case observed was: RX buffer length = 1536 bytes but
   rtw_rx_pkt_stat.pkt_len = 1546 bytes, this is not valid as it means
   we need to read beyond the end of the buffer)
- RX length looks valid but rtw_rx_pkt_stat.pkt_len is zero

Check if the RX_REQUEST is set in the HISR register for each iteration
inside rtw_sdio_rx_isr(). This mimics what the RTL8723DS vendor driver
does and makes the driver only read more data if the RX_REQUEST bit is
set (which seems to be a way for the card's hardware or firmware to
tell the host that data is ready to be processed).

For RTW_WCPU_11AC chips this check is not needed. The RTL8822BS vendor
driver for example states that this check is unnecessary (but still uses
it) and the RTL8822CS drops this check entirely.

Reviewed-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
Changes since v1:
- added Ping-Ke's Reviewed-by (thank you!)


 drivers/net/wireless/realtek/rtw88/sdio.c | 24 ++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

Comments

Kalle Valo May 25, 2023, 4:10 p.m. UTC | #1 
Martin Blumenstingl <martin.blumenstingl@googlemail.com> wrote:

> rtw_sdio_rx_isr() is responsible for receiving data from the wifi chip
> and is called from the SDIO interrupt handler when the interrupt status
> register (HISR) has the RX_REQUEST bit set. After the first batch of
> data has been processed by the driver the wifi chip may have more data
> ready to be read, which is managed by a loop in rtw_sdio_rx_isr().
> 
> It turns out that there are cases where the RX buffer length (from the
> REG_SDIO_RX0_REQ_LEN register) does not match the data we receive. The
> following two cases were observed with a RTL8723DS card:
> - RX length is smaller than the total packet length including overhead
>   and actual data bytes (whose length is part of the buffer we read from
>   the wifi chip and is stored in rtw_rx_pkt_stat.pkt_len). This can
>   result in errors like:
>     skbuff: skb_over_panic: text:ffff8000011924ac len:3341 put:3341
>   (one case observed was: RX buffer length = 1536 bytes but
>    rtw_rx_pkt_stat.pkt_len = 1546 bytes, this is not valid as it means
>    we need to read beyond the end of the buffer)
> - RX length looks valid but rtw_rx_pkt_stat.pkt_len is zero
> 
> Check if the RX_REQUEST is set in the HISR register for each iteration
> inside rtw_sdio_rx_isr(). This mimics what the RTL8723DS vendor driver
> does and makes the driver only read more data if the RX_REQUEST bit is
> set (which seems to be a way for the card's hardware or firmware to
> tell the host that data is ready to be processed).
> 
> For RTW_WCPU_11AC chips this check is not needed. The RTL8822BS vendor
> driver for example states that this check is unnecessary (but still uses
> it) and the RTL8822CS drops this check entirely.
> 
> Reviewed-by: Ping-Ke Shih <pkshih@realtek.com>
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>

4 patches applied to wireless-next.git, thanks.

e967229ead0e wifi: rtw88: sdio: Check the HISR RX_REQUEST bit in rtw_sdio_rx_isr()
9be20a822327 wifi: rtw88: rtw8723d: Implement RTL8723DS (SDIO) efuse parsing
09fcdbd28404 mmc: sdio: Add/rename SDIO ID of the RTL8723DS SDIO wifi cards
a3b125ceb45e wifi: rtw88: Add support for the SDIO based RTL8723DS chipset
Ulf Hansson May 26, 2023, 1:11 p.m. UTC | #2 
On Thu, 25 May 2023 at 18:10, Kalle Valo <kvalo@kernel.org> wrote:
>
> Martin Blumenstingl <martin.blumenstingl@googlemail.com> wrote:
>
> > rtw_sdio_rx_isr() is responsible for receiving data from the wifi chip
> > and is called from the SDIO interrupt handler when the interrupt status
> > register (HISR) has the RX_REQUEST bit set. After the first batch of
> > data has been processed by the driver the wifi chip may have more data
> > ready to be read, which is managed by a loop in rtw_sdio_rx_isr().
> >
> > It turns out that there are cases where the RX buffer length (from the
> > REG_SDIO_RX0_REQ_LEN register) does not match the data we receive. The
> > following two cases were observed with a RTL8723DS card:
> > - RX length is smaller than the total packet length including overhead
> >   and actual data bytes (whose length is part of the buffer we read from
> >   the wifi chip and is stored in rtw_rx_pkt_stat.pkt_len). This can
> >   result in errors like:
> >     skbuff: skb_over_panic: text:ffff8000011924ac len:3341 put:3341
> >   (one case observed was: RX buffer length = 1536 bytes but
> >    rtw_rx_pkt_stat.pkt_len = 1546 bytes, this is not valid as it means
> >    we need to read beyond the end of the buffer)
> > - RX length looks valid but rtw_rx_pkt_stat.pkt_len is zero
> >
> > Check if the RX_REQUEST is set in the HISR register for each iteration
> > inside rtw_sdio_rx_isr(). This mimics what the RTL8723DS vendor driver
> > does and makes the driver only read more data if the RX_REQUEST bit is
> > set (which seems to be a way for the card's hardware or firmware to
> > tell the host that data is ready to be processed).
> >
> > For RTW_WCPU_11AC chips this check is not needed. The RTL8822BS vendor
> > driver for example states that this check is unnecessary (but still uses
> > it) and the RTL8822CS drops this check entirely.
> >
> > Reviewed-by: Ping-Ke Shih <pkshih@realtek.com>
> > Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
>
> 4 patches applied to wireless-next.git, thanks.
>
> e967229ead0e wifi: rtw88: sdio: Check the HISR RX_REQUEST bit in rtw_sdio_rx_isr()
> 9be20a822327 wifi: rtw88: rtw8723d: Implement RTL8723DS (SDIO) efuse parsing
> 09fcdbd28404 mmc: sdio: Add/rename SDIO ID of the RTL8723DS SDIO wifi cards
> a3b125ceb45e wifi: rtw88: Add support for the SDIO based RTL8723DS chipset

If it's not too late, feel free to add my ack for patch3. Nevermind,
if it adds additional work for you.

Kind regards
Uffe
Kalle Valo May 26, 2023, 2:14 p.m. UTC | #3 
Ulf Hansson <ulf.hansson@linaro.org> writes:

> On Thu, 25 May 2023 at 18:10, Kalle Valo <kvalo@kernel.org> wrote:
>
>>
>> Martin Blumenstingl <martin.blumenstingl@googlemail.com> wrote:
>>
>> > rtw_sdio_rx_isr() is responsible for receiving data from the wifi chip
>> > and is called from the SDIO interrupt handler when the interrupt status
>> > register (HISR) has the RX_REQUEST bit set. After the first batch of
>> > data has been processed by the driver the wifi chip may have more data
>> > ready to be read, which is managed by a loop in rtw_sdio_rx_isr().
>> >
>> > It turns out that there are cases where the RX buffer length (from the
>> > REG_SDIO_RX0_REQ_LEN register) does not match the data we receive. The
>> > following two cases were observed with a RTL8723DS card:
>> > - RX length is smaller than the total packet length including overhead
>> >   and actual data bytes (whose length is part of the buffer we read from
>> >   the wifi chip and is stored in rtw_rx_pkt_stat.pkt_len). This can
>> >   result in errors like:
>> >     skbuff: skb_over_panic: text:ffff8000011924ac len:3341 put:3341
>> >   (one case observed was: RX buffer length = 1536 bytes but
>> >    rtw_rx_pkt_stat.pkt_len = 1546 bytes, this is not valid as it means
>> >    we need to read beyond the end of the buffer)
>> > - RX length looks valid but rtw_rx_pkt_stat.pkt_len is zero
>> >
>> > Check if the RX_REQUEST is set in the HISR register for each iteration
>> > inside rtw_sdio_rx_isr(). This mimics what the RTL8723DS vendor driver
>> > does and makes the driver only read more data if the RX_REQUEST bit is
>> > set (which seems to be a way for the card's hardware or firmware to
>> > tell the host that data is ready to be processed).
>> >
>> > For RTW_WCPU_11AC chips this check is not needed. The RTL8822BS vendor
>> > driver for example states that this check is unnecessary (but still uses
>> > it) and the RTL8822CS drops this check entirely.
>> >
>> > Reviewed-by: Ping-Ke Shih <pkshih@realtek.com>
>> > Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
>>
>> 4 patches applied to wireless-next.git, thanks.
>>
>> e967229ead0e wifi: rtw88: sdio: Check the HISR RX_REQUEST bit in rtw_sdio_rx_isr()
>> 9be20a822327 wifi: rtw88: rtw8723d: Implement RTL8723DS (SDIO) efuse parsing
>> 09fcdbd28404 mmc: sdio: Add/rename SDIO ID of the RTL8723DS SDIO wifi cards
>> a3b125ceb45e wifi: rtw88: Add support for the SDIO based RTL8723DS chipset
>
> If it's not too late, feel free to add my ack for patch3. Nevermind,
> if it adds additional work for you.

We don't rebase wireless trees so I can't add it anymore, sorry. But
thanks for reviewing it.
diff mbox series

Patch

diff --git a/drivers/net/wireless/realtek/rtw88/sdio.c b/drivers/net/wireless/realtek/rtw88/sdio.c
index 06fce7c3adda..2c1fb2dabd40 100644
--- a/drivers/net/wireless/realtek/rtw88/sdio.c
+++ b/drivers/net/wireless/realtek/rtw88/sdio.c
@@ -998,9 +998,9 @@  static void rtw_sdio_rxfifo_recv(struct rtw_dev *rtwdev, u32 rx_len)
 
 static void rtw_sdio_rx_isr(struct rtw_dev *rtwdev)
 {
-	u32 rx_len, total_rx_bytes = 0;
+	u32 rx_len, hisr, total_rx_bytes = 0;
 
-	while (total_rx_bytes < SZ_64K) {
+	do {
 		if (rtw_chip_wcpu_11n(rtwdev))
 			rx_len = rtw_read16(rtwdev, REG_SDIO_RX0_REQ_LEN);
 		else
@@ -1012,7 +1012,25 @@  static void rtw_sdio_rx_isr(struct rtw_dev *rtwdev)
 		rtw_sdio_rxfifo_recv(rtwdev, rx_len);
 
 		total_rx_bytes += rx_len;
-	}
+
+		if (rtw_chip_wcpu_11n(rtwdev)) {
+			/* Stop if no more RX requests are pending, even if
+			 * rx_len could be greater than zero in the next
+			 * iteration. This is needed because the RX buffer may
+			 * already contain data while either HW or FW are not
+			 * done filling that buffer yet. Still reading the
+			 * buffer can result in packets where
+			 * rtw_rx_pkt_stat.pkt_len is zero or points beyond the
+			 * end of the buffer.
+			 */
+			hisr = rtw_read32(rtwdev, REG_SDIO_HISR);
+		} else {
+			/* RTW_WCPU_11AC chips have improved hardware or
+			 * firmware and can use rx_len unconditionally.
+			 */
+			hisr = REG_SDIO_HISR_RX_REQUEST;
+		}
+	} while (total_rx_bytes < SZ_64K && hisr & REG_SDIO_HISR_RX_REQUEST);
 }
 
 static void rtw_sdio_handle_interrupt(struct sdio_func *sdio_func)