* [PATCH v1] i2c: designware: Do not complete i2c read without RX_FULL interrupt
@ 2021-12-11 4:16 tamal.saha
2021-12-13 11:43 ` Andy Shevchenko
0 siblings, 1 reply; 3+ messages in thread
From: tamal.saha @ 2021-12-11 4:16 UTC (permalink / raw)
To: wsa, andriy.shevchenko, jarkko.nikula, linux-i2c; +Cc: tamal.saha, bala.senthil
From: Tamal Saha <tamal.saha@intel.com>
Intel Keem Bay platform supports multimaster operations over same i2c
bus using Synopsis i2c designware IP. When multi masters initiate i2c
operation simultaneously in a loop, SCL line is stucked low forever
after few i2c operations. Following interrupt sequences are observed
in:
working case: TX_EMPTY, RX_FULL and STOP_DET
non working case: TX_EMPTY, STOP_DET, RX_FULL.
DW_apb_i2c stretches the SCL line when the TX FIFO is empty or when
RX FIFO is full. The DW_apb_i2c master will continue to hold the SCL
line LOW until RX FIFO is read.
Linux kernel i2c designware software does not handle above non working
sequence. TX_EMPTY, RX_FULL and STOP_DET routine execution are required
in sequence although RX_FULL interrupt is raised after STOP_DET by
hardware. Clear STOP_DET for following conditions
(STOP_DET ,RX_FULL, rx_outstanding)
Write Operation: (1, 0, 0)
Read Operation:
RX_FULL followed by STOP_DET: (0, 1, 1) -> (1, 0, 0)
STOP_DET followed by RX_FULL: (1, 0, 1) -> (1, 1, 0)
RX_FULL and STOP_DET together: (1, 1, 1)
Signed-off-by: Tamal Saha <tamal.saha@intel.com>
---
drivers/i2c/busses/i2c-designware-master.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c
index 9b08bb5df38d..9177463c2cbb 100644
--- a/drivers/i2c/busses/i2c-designware-master.c
+++ b/drivers/i2c/busses/i2c-designware-master.c
@@ -701,7 +701,8 @@ static u32 i2c_dw_read_clear_intrbits(struct dw_i2c_dev *dev)
regmap_read(dev->map, DW_IC_CLR_RX_DONE, &dummy);
if (stat & DW_IC_INTR_ACTIVITY)
regmap_read(dev->map, DW_IC_CLR_ACTIVITY, &dummy);
- if (stat & DW_IC_INTR_STOP_DET)
+ if ((stat & DW_IC_INTR_STOP_DET) &&
+ ((dev->rx_outstanding == 0) || (stat & DW_IC_INTR_RX_FULL)))
regmap_read(dev->map, DW_IC_CLR_STOP_DET, &dummy);
if (stat & DW_IC_INTR_START_DET)
regmap_read(dev->map, DW_IC_CLR_START_DET, &dummy);
@@ -723,6 +724,7 @@ static int i2c_dw_irq_handler_master(struct dw_i2c_dev *dev)
if (stat & DW_IC_INTR_TX_ABRT) {
dev->cmd_err |= DW_IC_ERR_TX_ABRT;
dev->status = STATUS_IDLE;
+ dev->rx_outstanding = 0;
/*
* Anytime TX_ABRT is set, the contents of the tx/rx
@@ -745,7 +747,8 @@ static int i2c_dw_irq_handler_master(struct dw_i2c_dev *dev)
*/
tx_aborted:
- if ((stat & (DW_IC_INTR_TX_ABRT | DW_IC_INTR_STOP_DET)) || dev->msg_err)
+ if (((stat & (DW_IC_INTR_TX_ABRT | DW_IC_INTR_STOP_DET)) || dev->msg_err) &&
+ (dev->rx_outstanding == 0))
complete(&dev->cmd_complete);
else if (unlikely(dev->flags & ACCESS_INTR_MASK)) {
/* Workaround to trigger pending interrupt */
--
2.17.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v1] i2c: designware: Do not complete i2c read without RX_FULL interrupt
2021-12-11 4:16 [PATCH v1] i2c: designware: Do not complete i2c read without RX_FULL interrupt tamal.saha
@ 2021-12-13 11:43 ` Andy Shevchenko
2021-12-14 2:26 ` Saha, Tamal
0 siblings, 1 reply; 3+ messages in thread
From: Andy Shevchenko @ 2021-12-13 11:43 UTC (permalink / raw)
To: tamal.saha; +Cc: wsa, jarkko.nikula, linux-i2c, bala.senthil
On Sat, Dec 11, 2021 at 09:46:43AM +0530, tamal.saha@intel.com wrote:
> From: Tamal Saha <tamal.saha@intel.com>
>
> Intel Keem Bay platform supports multimaster operations over same i2c
> bus using Synopsis i2c designware IP. When multi masters initiate i2c
Synopsys
DesignWare (and everywhere else in the text and comments).
> operation simultaneously in a loop, SCL line is stucked low forever
> after few i2c operations. Following interrupt sequences are observed
> in:
> working case: TX_EMPTY, RX_FULL and STOP_DET
> non working case: TX_EMPTY, STOP_DET, RX_FULL.
>
> DW_apb_i2c stretches the SCL line when the TX FIFO is empty or when
> RX FIFO is full. The DW_apb_i2c master will continue to hold the SCL
> line LOW until RX FIFO is read.
>
> Linux kernel i2c designware software does not handle above non working
software --> driver ?
> sequence. TX_EMPTY, RX_FULL and STOP_DET routine execution are required
> in sequence although RX_FULL interrupt is raised after STOP_DET by
> hardware. Clear STOP_DET for following conditions
the following
(and seems the colon is missed at the end of line)
> (STOP_DET ,RX_FULL, rx_outstanding)
> Write Operation: (1, 0, 0)
> Read Operation:
> RX_FULL followed by STOP_DET: (0, 1, 1) -> (1, 0, 0)
> STOP_DET followed by RX_FULL: (1, 0, 1) -> (1, 1, 0)
> RX_FULL and STOP_DET together: (1, 1, 1)
>
> Signed-off-by: Tamal Saha <tamal.saha@intel.com>
> ---
> drivers/i2c/busses/i2c-designware-master.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c
> index 9b08bb5df38d..9177463c2cbb 100644
> --- a/drivers/i2c/busses/i2c-designware-master.c
> +++ b/drivers/i2c/busses/i2c-designware-master.c
> @@ -701,7 +701,8 @@ static u32 i2c_dw_read_clear_intrbits(struct dw_i2c_dev *dev)
> regmap_read(dev->map, DW_IC_CLR_RX_DONE, &dummy);
> if (stat & DW_IC_INTR_ACTIVITY)
> regmap_read(dev->map, DW_IC_CLR_ACTIVITY, &dummy);
> - if (stat & DW_IC_INTR_STOP_DET)
> + if ((stat & DW_IC_INTR_STOP_DET) &&
> + ((dev->rx_outstanding == 0) || (stat & DW_IC_INTR_RX_FULL)))
> regmap_read(dev->map, DW_IC_CLR_STOP_DET, &dummy);
> if (stat & DW_IC_INTR_START_DET)
> regmap_read(dev->map, DW_IC_CLR_START_DET, &dummy);
> @@ -723,6 +724,7 @@ static int i2c_dw_irq_handler_master(struct dw_i2c_dev *dev)
> if (stat & DW_IC_INTR_TX_ABRT) {
> dev->cmd_err |= DW_IC_ERR_TX_ABRT;
> dev->status = STATUS_IDLE;
> + dev->rx_outstanding = 0;
>
> /*
> * Anytime TX_ABRT is set, the contents of the tx/rx
> @@ -745,7 +747,8 @@ static int i2c_dw_irq_handler_master(struct dw_i2c_dev *dev)
> */
>
> tx_aborted:
> - if ((stat & (DW_IC_INTR_TX_ABRT | DW_IC_INTR_STOP_DET)) || dev->msg_err)
> + if (((stat & (DW_IC_INTR_TX_ABRT | DW_IC_INTR_STOP_DET)) || dev->msg_err) &&
> + (dev->rx_outstanding == 0))
> complete(&dev->cmd_complete);
> else if (unlikely(dev->flags & ACCESS_INTR_MASK)) {
> /* Workaround to trigger pending interrupt */
> --
> 2.17.1
>
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 3+ messages in thread
* RE: [PATCH v1] i2c: designware: Do not complete i2c read without RX_FULL interrupt
2021-12-13 11:43 ` Andy Shevchenko
@ 2021-12-14 2:26 ` Saha, Tamal
0 siblings, 0 replies; 3+ messages in thread
From: Saha, Tamal @ 2021-12-14 2:26 UTC (permalink / raw)
To: Andy Shevchenko
Cc: wsa@kernel.org, jarkko.nikula@linux.intel.com,
linux-i2c@vger.kernel.org, Senthil, Bala
Thanks Andy. Will incorporate these findings and share next version patch.
-----Original Message-----
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Sent: Monday, 13 December, 2021 5:14 PM
To: Saha, Tamal <tamal.saha@intel.com>
Cc: wsa@kernel.org; jarkko.nikula@linux.intel.com; linux-i2c@vger.kernel.org; Senthil, Bala <bala.senthil@intel.com>
Subject: Re: [PATCH v1] i2c: designware: Do not complete i2c read without RX_FULL interrupt
On Sat, Dec 11, 2021 at 09:46:43AM +0530, tamal.saha@intel.com wrote:
> From: Tamal Saha <tamal.saha@intel.com>
>
> Intel Keem Bay platform supports multimaster operations over same i2c
> bus using Synopsis i2c designware IP. When multi masters initiate i2c
Synopsys
DesignWare (and everywhere else in the text and comments).
> operation simultaneously in a loop, SCL line is stucked low forever
> after few i2c operations. Following interrupt sequences are observed
> in:
> working case: TX_EMPTY, RX_FULL and STOP_DET
> non working case: TX_EMPTY, STOP_DET, RX_FULL.
>
> DW_apb_i2c stretches the SCL line when the TX FIFO is empty or when RX
> FIFO is full. The DW_apb_i2c master will continue to hold the SCL line
> LOW until RX FIFO is read.
>
> Linux kernel i2c designware software does not handle above non working
software --> driver ?
> sequence. TX_EMPTY, RX_FULL and STOP_DET routine execution are
> required in sequence although RX_FULL interrupt is raised after
> STOP_DET by hardware. Clear STOP_DET for following conditions
the following
(and seems the colon is missed at the end of line)
> (STOP_DET ,RX_FULL, rx_outstanding)
> Write Operation: (1, 0, 0)
> Read Operation:
> RX_FULL followed by STOP_DET: (0, 1, 1) -> (1, 0, 0)
> STOP_DET followed by RX_FULL: (1, 0, 1) -> (1, 1, 0)
> RX_FULL and STOP_DET together: (1, 1, 1)
>
> Signed-off-by: Tamal Saha <tamal.saha@intel.com>
> ---
> drivers/i2c/busses/i2c-designware-master.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-designware-master.c
> b/drivers/i2c/busses/i2c-designware-master.c
> index 9b08bb5df38d..9177463c2cbb 100644
> --- a/drivers/i2c/busses/i2c-designware-master.c
> +++ b/drivers/i2c/busses/i2c-designware-master.c
> @@ -701,7 +701,8 @@ static u32 i2c_dw_read_clear_intrbits(struct dw_i2c_dev *dev)
> regmap_read(dev->map, DW_IC_CLR_RX_DONE, &dummy);
> if (stat & DW_IC_INTR_ACTIVITY)
> regmap_read(dev->map, DW_IC_CLR_ACTIVITY, &dummy);
> - if (stat & DW_IC_INTR_STOP_DET)
> + if ((stat & DW_IC_INTR_STOP_DET) &&
> + ((dev->rx_outstanding == 0) || (stat & DW_IC_INTR_RX_FULL)))
> regmap_read(dev->map, DW_IC_CLR_STOP_DET, &dummy);
> if (stat & DW_IC_INTR_START_DET)
> regmap_read(dev->map, DW_IC_CLR_START_DET, &dummy); @@ -723,6
> +724,7 @@ static int i2c_dw_irq_handler_master(struct dw_i2c_dev *dev)
> if (stat & DW_IC_INTR_TX_ABRT) {
> dev->cmd_err |= DW_IC_ERR_TX_ABRT;
> dev->status = STATUS_IDLE;
> + dev->rx_outstanding = 0;
>
> /*
> * Anytime TX_ABRT is set, the contents of the tx/rx @@ -745,7
> +747,8 @@ static int i2c_dw_irq_handler_master(struct dw_i2c_dev *dev)
> */
>
> tx_aborted:
> - if ((stat & (DW_IC_INTR_TX_ABRT | DW_IC_INTR_STOP_DET)) || dev->msg_err)
> + if (((stat & (DW_IC_INTR_TX_ABRT | DW_IC_INTR_STOP_DET)) || dev->msg_err) &&
> + (dev->rx_outstanding == 0))
> complete(&dev->cmd_complete);
> else if (unlikely(dev->flags & ACCESS_INTR_MASK)) {
> /* Workaround to trigger pending interrupt */
> --
> 2.17.1
>
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-12-11 4:16 [PATCH v1] i2c: designware: Do not complete i2c read without RX_FULL interrupt tamal.saha
2021-12-13 11:43 ` Andy Shevchenko
2021-12-14 2:26 ` Saha, Tamal
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