Re: [PATCH v4 2/6] cxl: Add CXL spec v3.0 interleave support

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

On Wed, 17 Aug 2022 14:21:48 -0700
Dave Jiang <dave.jiang@intel.com> wrote:

> CXL spec v3.0 added 2 CAP bits to the CXL HDM Decoder Capability Register.
> CXL spec v3.0 8.2.4.19.1. Bit 11 indicates that 3, 6, and 12 way interleave
> is capable. Bit 12 indicates that 16 way interleave is capable.
> 
> Add code to parse_hdm_decoder_caps() to cache those new bits. Add check in
> cxl_interleave_verify() call to make sure those CAP bits matches the passed
Whilst looking at mocking patch, I noticed there isn't a cxl_interleave_verify()
renamed?  Looks like that was in v2 from your change log.

> in interleave value.
> 
> Reviewed-by: Dan Williams <dan.j.williams@intel.com>
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
> ---
>  drivers/cxl/core/hdm.c    |    6 ++++++
>  drivers/cxl/core/region.c |    3 +++
>  drivers/cxl/cxl.h         |    2 ++
>  drivers/cxl/cxlmem.h      |    5 +++++
>  4 files changed, 16 insertions(+)
> 
> diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
> index d1d2caea5c62..2f91ff9b0227 100644
> --- a/drivers/cxl/core/hdm.c
> +++ b/drivers/cxl/core/hdm.c
> @@ -80,6 +80,12 @@ static void parse_hdm_decoder_caps(struct cxl_hdm *cxlhdm)
>  		cxlhdm->interleave_mask |= GENMASK(11, 8);
>  	if (FIELD_GET(CXL_HDM_DECODER_INTERLEAVE_14_12, hdm_cap))
>  		cxlhdm->interleave_mask |= GENMASK(14, 12);
> +
> +	cxlhdm->interleave_cap = CXL_HDM_INTERLEAVE_CAP_DEFAULT;
> +	if (FIELD_GET(CXL_HDM_DECODER_INTERLEAVE_3_6_12_WAY, hdm_cap))
> +		cxlhdm->interleave_cap |= CXL_HDM_INTERLEAVE_CAP_3_6_12;
> +	if (FIELD_GET(CXL_HDM_DECODER_INTERLEAVE_16_WAY, hdm_cap))
> +		cxlhdm->interleave_cap |= CXL_HDM_INTERLEAVE_CAP_16;
>  }
>  
>  static void __iomem *map_hdm_decoder_regs(struct cxl_port *port,
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index 28272b0196e6..9851ab2782f2 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -960,6 +960,9 @@ static int cxl_interleave_capable(struct cxl_port *port, struct device *dev,
>  	if (eiw == 0)
>  		return 0;
>  
> +	if (!test_bit(ways, &cxlhdm->interleave_cap))
> +		return -EINVAL;
> +
>  	if (is_power_of_2(eiw))
>  		addr_mask = GENMASK(eig + 8 + eiw - 1, eig + 8);
>  	else
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index f680450f0b16..11f2a14f42eb 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -42,6 +42,8 @@
>  #define   CXL_HDM_DECODER_TARGET_COUNT_MASK GENMASK(7, 4)
>  #define   CXL_HDM_DECODER_INTERLEAVE_11_8 BIT(8)
>  #define   CXL_HDM_DECODER_INTERLEAVE_14_12 BIT(9)
> +#define   CXL_HDM_DECODER_INTERLEAVE_3_6_12_WAY BIT(11)
> +#define   CXL_HDM_DECODER_INTERLEAVE_16_WAY BIT(12)
>  #define CXL_HDM_DECODER_CTRL_OFFSET 0x4
>  #define   CXL_HDM_DECODER_ENABLE BIT(1)
>  #define CXL_HDM_DECODER0_BASE_LOW_OFFSET(i) (0x20 * (i) + 0x10)
> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
> index 88e3a8e54b6a..4e65c9cc1d30 100644
> --- a/drivers/cxl/cxlmem.h
> +++ b/drivers/cxl/cxlmem.h
> @@ -393,11 +393,16 @@ static inline void cxl_mem_active_dec(void)
>  }
>  #endif
>  
> +#define CXL_HDM_INTERLEAVE_CAP_DEFAULT BIT(1) | BIT(2) | BIT(4) | BIT(8)
> +#define CXL_HDM_INTERLEAVE_CAP_3_6_12 BIT(3) | BIT(6) | BIT(12)
> +#define CXL_HDM_INTERLEAVE_CAP_16 BIT(16)
> +
>  struct cxl_hdm {
>  	struct cxl_component_regs regs;
>  	unsigned int decoder_count;
>  	unsigned int target_count;
>  	unsigned int interleave_mask;
> +	unsigned long interleave_cap;
>  	struct cxl_port *port;
>  };
>  
> 
>