As per Errata i2310[0], Erroneous timeout can be triggered,
if this Erroneous interrupt is not cleared then it may leads
to strom of interrupts, therefore apply Errata i2310 solution.
[0] https://www.ti.com/lit/pdf/sprz536 page 23
Signed-off-by: Udit Kumar <[email protected]>
---
drivers/tty/serial/8250/8250_omap.c | 25 ++++++++++++++++++++-----
1 file changed, 20 insertions(+), 5 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
index 170639d12b2a..38eb639f78d3 100644
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -115,6 +115,10 @@
/* RX FIFO occupancy indicator */
#define UART_OMAP_RX_LVL 0x19
+/* Timeout Low and High */
+#define UART_OMAP_TO_L 0x26
+#define UART_OMAP_TO_H 0x27
+
/*
* Copy of the genpd flags for the console.
* Only used if console suspend is disabled
@@ -663,13 +667,24 @@ static irqreturn_t omap8250_irq(int irq, void *dev_id)
/*
* On K3 SoCs, it is observed that RX TIMEOUT is signalled after
- * FIFO has been drained, in which case a dummy read of RX FIFO
- * is required to clear RX TIMEOUT condition.
+ * FIFO has been drained or erroneously.
+ * So apply solution of Errata i2310 as mentioned in
+ * https://www.ti.com/lit/pdf/sprz536
*/
if (priv->habit & UART_RX_TIMEOUT_QUIRK &&
- (iir & UART_IIR_RX_TIMEOUT) == UART_IIR_RX_TIMEOUT &&
- serial_port_in(port, UART_OMAP_RX_LVL) == 0) {
- serial_port_in(port, UART_RX);
+ (iir & UART_IIR_RX_TIMEOUT) == UART_IIR_RX_TIMEOUT) {
+ unsigned char efr2, timeout_h, timeout_l;
+
+ efr2 = serial_in(up, UART_OMAP_EFR2);
+ timeout_h = serial_in(up, UART_OMAP_TO_H);
+ timeout_l = serial_in(up, UART_OMAP_TO_L);
+ serial_out(up, UART_OMAP_TO_H, 0xFF);
+ serial_out(up, UART_OMAP_TO_L, 0xFF);
+ serial_out(up, UART_OMAP_EFR2, 0x1);
+ serial_in(up, UART_IIR);
+ serial_out(up, UART_OMAP_EFR2, efr2);
+ serial_out(up, UART_OMAP_TO_H, timeout_h);
+ serial_out(up, UART_OMAP_TO_L, timeout_l);
}
/* Stop processing interrupts on input overrun */
--
2.34.1
On Fri, Jun 14, 2024 at 11:43:14AM +0530, Udit Kumar wrote:
> As per Errata i2310[0], Erroneous timeout can be triggered,
> if this Erroneous interrupt is not cleared then it may leads
> to strom of interrupts, therefore apply Errata i2310 solution.
>
> [0] https://www.ti.com/lit/pdf/sprz536 page 23
>
> Signed-off-by: Udit Kumar <[email protected]>
> ---
> drivers/tty/serial/8250/8250_omap.c | 25 ++++++++++++++++++++-----
> 1 file changed, 20 insertions(+), 5 deletions(-)
Does this need to go to older/stable kernels? If so, how far back?
thanks,
greg k-h
On 14/06/24 12:16, Greg KH wrote:
> On Fri, Jun 14, 2024 at 11:43:14AM +0530, Udit Kumar wrote:
>> As per Errata i2310[0], Erroneous timeout can be triggered,
>> if this Erroneous interrupt is not cleared then it may leads
>> to strom of interrupts, therefore apply Errata i2310 solution.
>>
s/strom/storm
>> [0] https://www.ti.com/lit/pdf/sprz536 page 23
>>
>> Signed-off-by: Udit Kumar <[email protected]>
>> ---
>> drivers/tty/serial/8250/8250_omap.c | 25 ++++++++++++++++++++-----
>> 1 file changed, 20 insertions(+), 5 deletions(-)
>
> Does this need to go to older/stable kernels? If so, how far back?
>
Yes, this seems to be an updated workaround to existing errata.
Please add below Fixes tag when you respin
Fixes: b67e830d38fa ("serial: 8250: 8250_omap: Fix possible interrupt storm on K3 SoCs")
> thanks,
>
> greg k-h
--
Regards
Vignesh
On Fri, 14 Jun 2024, Udit Kumar wrote:
> As per Errata i2310[0], Erroneous timeout can be triggered,
> if this Erroneous interrupt is not cleared then it may leads
> to strom of interrupts, therefore apply Errata i2310 solution.
>
> [0] https://www.ti.com/lit/pdf/sprz536 page 23
>
> Signed-off-by: Udit Kumar <[email protected]>
> ---
> drivers/tty/serial/8250/8250_omap.c | 25 ++++++++++++++++++++-----
> 1 file changed, 20 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
> index 170639d12b2a..38eb639f78d3 100644
> --- a/drivers/tty/serial/8250/8250_omap.c
> +++ b/drivers/tty/serial/8250/8250_omap.c
> @@ -115,6 +115,10 @@
> /* RX FIFO occupancy indicator */
> #define UART_OMAP_RX_LVL 0x19
>
> +/* Timeout Low and High */
> +#define UART_OMAP_TO_L 0x26
> +#define UART_OMAP_TO_H 0x27
> +
> /*
> * Copy of the genpd flags for the console.
> * Only used if console suspend is disabled
> @@ -663,13 +667,24 @@ static irqreturn_t omap8250_irq(int irq, void *dev_id)
>
> /*
> * On K3 SoCs, it is observed that RX TIMEOUT is signalled after
> - * FIFO has been drained, in which case a dummy read of RX FIFO
> - * is required to clear RX TIMEOUT condition.
> + * FIFO has been drained or erroneously.
> + * So apply solution of Errata i2310 as mentioned in
> + * https://www.ti.com/lit/pdf/sprz536
> */
> if (priv->habit & UART_RX_TIMEOUT_QUIRK &&
> - (iir & UART_IIR_RX_TIMEOUT) == UART_IIR_RX_TIMEOUT &&
> - serial_port_in(port, UART_OMAP_RX_LVL) == 0) {
> - serial_port_in(port, UART_RX);
> + (iir & UART_IIR_RX_TIMEOUT) == UART_IIR_RX_TIMEOUT) {
> + unsigned char efr2, timeout_h, timeout_l;
> +
> + efr2 = serial_in(up, UART_OMAP_EFR2);
> + timeout_h = serial_in(up, UART_OMAP_TO_H);
> + timeout_l = serial_in(up, UART_OMAP_TO_L);
> + serial_out(up, UART_OMAP_TO_H, 0xFF);
> + serial_out(up, UART_OMAP_TO_L, 0xFF);
> + serial_out(up, UART_OMAP_EFR2, 0x1);
Eh, this doesn't match the workaround in the errata???
Also, don't use literals but name the bits with defines (for the correct
bit there's probably a pre-existing define but it's not named as good as
it could be, I'd say it should be named as
UART_OMAP_EFR2_TIMEOUT_PERIODIC).
> + serial_in(up, UART_IIR);
> + serial_out(up, UART_OMAP_EFR2, efr2);
> + serial_out(up, UART_OMAP_TO_H, timeout_h);
> + serial_out(up, UART_OMAP_TO_L, timeout_l);
--
i.
On 6/14/2024 1:58 PM, Ilpo Järvinen wrote:
> On Fri, 14 Jun 2024, Udit Kumar wrote:
>
>> As per Errata i2310[0], Erroneous timeout can be triggered,
>> if this Erroneous interrupt is not cleared then it may leads
>> to strom of interrupts, therefore apply Errata i2310 solution.
>>
>> [0] https://www.ti.com/lit/pdf/sprz536 page 23
>>
>> Signed-off-by: Udit Kumar <[email protected]>
>> ---
>> drivers/tty/serial/8250/8250_omap.c | 25 ++++++++++++++++++++-----
>> 1 file changed, 20 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
>> index 170639d12b2a..38eb639f78d3 100644
>> --- a/drivers/tty/serial/8250/8250_omap.c
>> +++ b/drivers/tty/serial/8250/8250_omap.c
>> @@ -115,6 +115,10 @@
>> /* RX FIFO occupancy indicator */
>> #define UART_OMAP_RX_LVL 0x19
>>
>> +/* Timeout Low and High */
>> +#define UART_OMAP_TO_L 0x26
>> +#define UART_OMAP_TO_H 0x27
>> +
>> /*
>> * Copy of the genpd flags for the console.
>> * Only used if console suspend is disabled
>> @@ -663,13 +667,24 @@ static irqreturn_t omap8250_irq(int irq, void *dev_id)
>>
>> /*
>> * On K3 SoCs, it is observed that RX TIMEOUT is signalled after
>> - * FIFO has been drained, in which case a dummy read of RX FIFO
>> - * is required to clear RX TIMEOUT condition.
>> + * FIFO has been drained or erroneously.
>> + * So apply solution of Errata i2310 as mentioned in
>> + * https://www.ti.com/lit/pdf/sprz536
>> */
>> if (priv->habit & UART_RX_TIMEOUT_QUIRK &&
>> - (iir & UART_IIR_RX_TIMEOUT) == UART_IIR_RX_TIMEOUT &&
>> - serial_port_in(port, UART_OMAP_RX_LVL) == 0) {
>> - serial_port_in(port, UART_RX);
>> + (iir & UART_IIR_RX_TIMEOUT) == UART_IIR_RX_TIMEOUT) {
>> + unsigned char efr2, timeout_h, timeout_l;
>> +
>> + efr2 = serial_in(up, UART_OMAP_EFR2);
>> + timeout_h = serial_in(up, UART_OMAP_TO_H);
>> + timeout_l = serial_in(up, UART_OMAP_TO_L);
>> + serial_out(up, UART_OMAP_TO_H, 0xFF);
>> + serial_out(up, UART_OMAP_TO_L, 0xFF);
>> + serial_out(up, UART_OMAP_EFR2, 0x1);
> Eh, this doesn't match the workaround in the errata???
>
> Also, don't use literals but name the bits with defines (for the correct
> bit there's probably a pre-existing define but it's not named as good as
> it could be, I'd say it should be named as
> UART_OMAP_EFR2_TIMEOUT_PERIODIC).
Thanks, will address in v2.
>
>> + serial_in(up, UART_IIR);
>> + serial_out(up, UART_OMAP_EFR2, efr2);
>> + serial_out(up, UART_OMAP_TO_H, timeout_h);
>> + serial_out(up, UART_OMAP_TO_L, timeout_l);