[v3] cxl: mask slice error interrupts after first occurrence

From: Alastair D'Silva <alastair@d-silva.org>

In some situations, a faulty AFU slice may create an interrupt storm,
rendering the machine unusable. Since these interrupts are informational
only, present the interrupt once, then mask it off to prevent it from
being retriggered until the card is reset.

Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
---
Changelog:
v3
	Add CXL_PSL_SERR_An_IRQS, CXL_PSL_SERR_An_IRQ_MASKS macros
	Explicitly reenable masked interrupts after reset
	Issue an info line that subsequent interrupts will be masked
v2
        Rebase against linux-next

---
 drivers/misc/cxl/cxl.h    | 18 ++++++++++++++++++
 drivers/misc/cxl/native.c | 19 +++++++++++++++++--
 2 files changed, 35 insertions(+), 2 deletions(-)

On 28/04/17 13:20, Alastair D'Silva wrote:
> From: Alastair D'Silva <alastair@d-silva.org>
>
> In some situations, a faulty AFU slice may create an interrupt storm,
> rendering the machine unusable. Since these interrupts are informational
> only, present the interrupt once, then mask it off to prevent it from
> being retriggered until the card is reset.
>
> Signed-off-by: Alastair D'Silva <alastair@d-silva.org>

LGTM

Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>

Hi Alastair,

Thanks for addressing previous review comments. Few additional and very
minor comments.

Alastair D'Silva <alastair@au1.ibm.com> writes:
> From: Alastair D'Silva <alastair@d-silva.org>
>
> In some situations, a faulty AFU slice may create an interrupt storm,
'interrupt storm of slice-errors,'
> rendering the machine unusable. Since these interrupts are informational
> only, present the interrupt once, then mask it off to prevent it from
> being retriggered until the card is reset.
s|card|card/afu

> @@ -1226,7 +1237,11 @@ static irqreturn_t native_slice_irq_err(int irq, void *data)
>  	dev_crit(&afu->dev, "AFU_ERR_An: 0x%.16llx\n", afu_error);
>  	dev_crit(&afu->dev, "PSL_DSISR_An: 0x%.16llx\n", dsisr);
>
> +	/* mask off the IRQ so it won't retrigger until the card is reset */
> +	irq_mask = (serr & CXL_PSL_SERR_An_IRQS) >> 32;
> +	serr |= irq_mask;
>  	cxl_p1n_write(afu, CXL_PSL_SERR_An, serr);
> +	dev_info(&afu->dev, "Further interrupts will be masked until the
Optional: Just to be explicit, since you are only masking a subset of possible
slice errors hence I would suggest rephrasing the message as:
"Further such interrupts....

> AFU is reset\n");
To be consistent with the patch description  s|AFU|AFU/Card

Hi Alastair,


Le 28/04/2017 à 05:20, Alastair D'Silva a écrit :
> From: Alastair D'Silva <alastair@d-silva.org>
>
> In some situations, a faulty AFU slice may create an interrupt storm,
> rendering the machine unusable. Since these interrupts are informational
> only, present the interrupt once, then mask it off to prevent it from
> being retriggered until the card is reset.
>
> Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
> ---
> Changelog:
> v3
> 	Add CXL_PSL_SERR_An_IRQS, CXL_PSL_SERR_An_IRQ_MASKS macros
> 	Explicitly reenable masked interrupts after reset
> 	Issue an info line that subsequent interrupts will be masked
> v2
>         Rebase against linux-next
>
> ---
>  drivers/misc/cxl/cxl.h    | 18 ++++++++++++++++++
>  drivers/misc/cxl/native.c | 19 +++++++++++++++++--
>  2 files changed, 35 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/misc/cxl/cxl.h b/drivers/misc/cxl/cxl.h
> index 452e209..6b00952 100644
> --- a/drivers/misc/cxl/cxl.h
> +++ b/drivers/misc/cxl/cxl.h
> @@ -228,6 +228,24 @@ static const cxl_p2n_reg_t CXL_PSL_WED_An     = {0x0A0};
>  #define CXL_PSL_SERR_An_llcmdto	(1ull << (63-6))
>  #define CXL_PSL_SERR_An_afupar	(1ull << (63-7))
>  #define CXL_PSL_SERR_An_afudup	(1ull << (63-8))
> +#define CXL_PSL_SERR_An_IRQS	( \
> +	CXL_PSL_SERR_An_afuto | CXL_PSL_SERR_An_afudup | CXL_PSL_SERR_An_afuov | \
> +	CXL_PSL_SERR_An_badsrc | CXL_PSL_SERR_An_badctx | CXL_PSL_SERR_An_llcmdis | \
> +	CXL_PSL_SERR_An_llcmdto | CXL_PSL_SERR_An_afupar | CXL_PSL_SERR_An_afudup)

arg, thanks for cleaning that up. As mentioned in a different thread, it 
didn't have to fall on you.

However, there's a cut-and-paste issue here: 'afudis' is missing (the 
2nd one) and 'afudup' is listed twice.

Same in the mask below.



> +#define CXL_PSL_SERR_An_afuto_mask	(1ull << (63-32))
> +#define CXL_PSL_SERR_An_afudis_mask	(1ull << (63-33))
> +#define CXL_PSL_SERR_An_afuov_mask	(1ull << (63-34))
> +#define CXL_PSL_SERR_An_badsrc_mask	(1ull << (63-35))
> +#define CXL_PSL_SERR_An_badctx_mask	(1ull << (63-36))
> +#define CXL_PSL_SERR_An_llcmdis_mask	(1ull << (63-37))
> +#define CXL_PSL_SERR_An_llcmdto_mask	(1ull << (63-38))
> +#define CXL_PSL_SERR_An_afupar_mask	(1ull << (63-39))
> +#define CXL_PSL_SERR_An_afudup_mask	(1ull << (63-40))
> +#define CXL_PSL_SERR_An_IRQ_MASKS	( \
> +	CXL_PSL_SERR_An_afuto_mask | CXL_PSL_SERR_An_afudup_mask | CXL_PSL_SERR_An_afuov_mask | \
> +	CXL_PSL_SERR_An_badsrc_mask | CXL_PSL_SERR_An_badctx_mask | CXL_PSL_SERR_An_llcmdis_mask | \
> +	CXL_PSL_SERR_An_llcmdto_mask | CXL_PSL_SERR_An_afupar_mask | CXL_PSL_SERR_An_afudup_mask)
> +


^^^

With those corrected:
Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>

Thanks for the patch.

   Fred


>  #define CXL_PSL_SERR_An_AE	(1ull << (63-30))
>
>  /****** CXL_PSL_SCNTL_An ****************************************************/
> diff --git a/drivers/misc/cxl/native.c b/drivers/misc/cxl/native.c
> index 194c58e..3e7fc86 100644
> --- a/drivers/misc/cxl/native.c
> +++ b/drivers/misc/cxl/native.c
> @@ -95,12 +95,23 @@ int cxl_afu_disable(struct cxl_afu *afu)
>  /* This will disable as well as reset */
>  static int native_afu_reset(struct cxl_afu *afu)
>  {
> +	int rc;
> +	u64 serr;
> +
>  	pr_devel("AFU reset request\n");
>
> -	return afu_control(afu, CXL_AFU_Cntl_An_RA, 0,
> +	rc = afu_control(afu, CXL_AFU_Cntl_An_RA, 0,
>  			   CXL_AFU_Cntl_An_RS_Complete | CXL_AFU_Cntl_An_ES_Disabled,
>  			   CXL_AFU_Cntl_An_RS_MASK | CXL_AFU_Cntl_An_ES_MASK,
>  			   false);
> +
> +	/* Re-enable any masked interrupts */
> +	serr = cxl_p1n_read(afu, CXL_PSL_SERR_An);
> +	serr &= ~CXL_PSL_SERR_An_IRQ_MASKS;
> +	cxl_p1n_write(afu, CXL_PSL_SERR_An, serr);
> +
> +
> +	return rc;
>  }
>
>  static int native_afu_check_and_enable(struct cxl_afu *afu)
> @@ -1205,7 +1216,7 @@ static irqreturn_t native_slice_irq_err(int irq, void *data)
>  {
>  	struct cxl_afu *afu = data;
>  	u64 errstat, serr, afu_error, dsisr;
> -	u64 fir_slice, afu_debug;
> +	u64 fir_slice, afu_debug, irq_mask;
>
>  	/*
>  	 * slice err interrupt is only used with full PSL (no XSL)
> @@ -1226,7 +1237,11 @@ static irqreturn_t native_slice_irq_err(int irq, void *data)
>  	dev_crit(&afu->dev, "AFU_ERR_An: 0x%.16llx\n", afu_error);
>  	dev_crit(&afu->dev, "PSL_DSISR_An: 0x%.16llx\n", dsisr);
>
> +	/* mask off the IRQ so it won't retrigger until the card is reset */
> +	irq_mask = (serr & CXL_PSL_SERR_An_IRQS) >> 32;
> +	serr |= irq_mask;
>  	cxl_p1n_write(afu, CXL_PSL_SERR_An, serr);
> +	dev_info(&afu->dev, "Further interrupts will be masked until the AFU is reset\n");
>
>  	return IRQ_HANDLED;
>  }
>