Re: [PATCH v4 2/3] platform/mellanox: mlxbf-pmc: Fix reading of unprogrammed events

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 9/5/23 14:49, Shravan Kumar Ramani wrote:
> This fix involves 2 changes:
>  - All event regs have a reset value of 0, which is not a valid
>    event_number as per the event_list for most blocks and hence seen
>    as an error. Add a "disable" event with event_number 0 for all blocks.
> 
>  - The enable bit for each counter need not be checked before
>    reading the event info, and hence removed.
> 
> Fixes: 1a218d312e65 ("platform/mellanox: mlxbf-pmc: Add Mellanox BlueField PMC driver")
> Signed-off-by: Shravan Kumar Ramani <shravankr@nvidia.com>
> Reviewed-by: Vadim Pasternak <vadimp@nvidia.com>
> Reviewed-by: David Thompson <davthompson@nvidia.com>

Thank you for your patch, I've applied this patch to my fixes
branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=fixes

Note it will show up in my fixes branch once I've pushed my
local branch there, which might take a while.

I will include this patch in my next fixes pull-req to Linus
for the current kernel development cycle.

Regards,

Hans


> ---
>  drivers/platform/mellanox/mlxbf-pmc.c | 27 +++++++--------------------
>  1 file changed, 7 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/platform/mellanox/mlxbf-pmc.c b/drivers/platform/mellanox/mlxbf-pmc.c
> index 95afcae7b9fa..2d4bbe99959e 100644
> --- a/drivers/platform/mellanox/mlxbf-pmc.c
> +++ b/drivers/platform/mellanox/mlxbf-pmc.c
> @@ -191,6 +191,7 @@ static const struct mlxbf_pmc_events mlxbf_pmc_smgen_events[] = {
>  };
>  
>  static const struct mlxbf_pmc_events mlxbf_pmc_trio_events_1[] = {
> +	{ 0x0, "DISABLE" },
>  	{ 0xa0, "TPIO_DATA_BEAT" },
>  	{ 0xa1, "TDMA_DATA_BEAT" },
>  	{ 0xa2, "MAP_DATA_BEAT" },
> @@ -214,6 +215,7 @@ static const struct mlxbf_pmc_events mlxbf_pmc_trio_events_1[] = {
>  };
>  
>  static const struct mlxbf_pmc_events mlxbf_pmc_trio_events_2[] = {
> +	{ 0x0, "DISABLE" },
>  	{ 0xa0, "TPIO_DATA_BEAT" },
>  	{ 0xa1, "TDMA_DATA_BEAT" },
>  	{ 0xa2, "MAP_DATA_BEAT" },
> @@ -246,6 +248,7 @@ static const struct mlxbf_pmc_events mlxbf_pmc_trio_events_2[] = {
>  };
>  
>  static const struct mlxbf_pmc_events mlxbf_pmc_ecc_events[] = {
> +	{ 0x0, "DISABLE" },
>  	{ 0x100, "ECC_SINGLE_ERROR_CNT" },
>  	{ 0x104, "ECC_DOUBLE_ERROR_CNT" },
>  	{ 0x114, "SERR_INJ" },
> @@ -258,6 +261,7 @@ static const struct mlxbf_pmc_events mlxbf_pmc_ecc_events[] = {
>  };
>  
>  static const struct mlxbf_pmc_events mlxbf_pmc_mss_events[] = {
> +	{ 0x0, "DISABLE" },
>  	{ 0xc0, "RXREQ_MSS" },
>  	{ 0xc1, "RXDAT_MSS" },
>  	{ 0xc2, "TXRSP_MSS" },
> @@ -265,6 +269,7 @@ static const struct mlxbf_pmc_events mlxbf_pmc_mss_events[] = {
>  };
>  
>  static const struct mlxbf_pmc_events mlxbf_pmc_hnf_events[] = {
> +	{ 0x0, "DISABLE" },
>  	{ 0x45, "HNF_REQUESTS" },
>  	{ 0x46, "HNF_REJECTS" },
>  	{ 0x47, "ALL_BUSY" },
> @@ -323,6 +328,7 @@ static const struct mlxbf_pmc_events mlxbf_pmc_hnf_events[] = {
>  };
>  
>  static const struct mlxbf_pmc_events mlxbf_pmc_hnfnet_events[] = {
> +	{ 0x0, "DISABLE" },
>  	{ 0x12, "CDN_REQ" },
>  	{ 0x13, "DDN_REQ" },
>  	{ 0x14, "NDN_REQ" },
> @@ -892,7 +898,7 @@ static int mlxbf_pmc_read_event(int blk_num, uint32_t cnt_num, bool is_l3,
>  				uint64_t *result)
>  {
>  	uint32_t perfcfg_offset, perfval_offset;
> -	uint64_t perfmon_cfg, perfevt, perfctl;
> +	uint64_t perfmon_cfg, perfevt;
>  
>  	if (cnt_num >= pmc->block[blk_num].counters)
>  		return -EINVAL;
> @@ -904,25 +910,6 @@ static int mlxbf_pmc_read_event(int blk_num, uint32_t cnt_num, bool is_l3,
>  	perfval_offset = perfcfg_offset +
>  			 pmc->block[blk_num].counters * MLXBF_PMC_REG_SIZE;
>  
> -	/* Set counter in "read" mode */
> -	perfmon_cfg = FIELD_PREP(MLXBF_PMC_PERFMON_CONFIG_ADDR,
> -				 MLXBF_PMC_PERFCTL);
> -	perfmon_cfg |= FIELD_PREP(MLXBF_PMC_PERFMON_CONFIG_STROBE, 1);
> -	perfmon_cfg |= FIELD_PREP(MLXBF_PMC_PERFMON_CONFIG_WR_R_B, 0);
> -
> -	if (mlxbf_pmc_write(pmc->block[blk_num].mmio_base + perfcfg_offset,
> -			    MLXBF_PMC_WRITE_REG_64, perfmon_cfg))
> -		return -EFAULT;
> -
> -	/* Check if the counter is enabled */
> -
> -	if (mlxbf_pmc_read(pmc->block[blk_num].mmio_base + perfval_offset,
> -			   MLXBF_PMC_READ_REG_64, &perfctl))
> -		return -EFAULT;
> -
> -	if (!FIELD_GET(MLXBF_PMC_PERFCTL_EN0, perfctl))
> -		return -EINVAL;
> -
>  	/* Set counter in "read" mode */
>  	perfmon_cfg = FIELD_PREP(MLXBF_PMC_PERFMON_CONFIG_ADDR,
>  				 MLXBF_PMC_PERFEVT);