Re: [PATCH 04/26] cxl/region: Add dynamic capacity decoder and region modes

Dave Jiang
2024-03-27T15:43:23Z

On 3/24/24 4:18 PM, ira.weiny@intel.com wrote:
> From: Navneet Singh <navneet.singh@intel.com>
>
> Region mode must reflect a general dynamic capacity type which is
> associated with a specific Dynamic Capacity (DC) partitions in each
> device decoder within the region. DC partitions are also know as DC
> regions per CXL 3.1.

This section reads somewhat awkward to me. Does this read any better?

One or more Dynamic Capacity (DC) partitions (and decoders) form a CXL software region. The region mode reflects composition of that entire software region. Decoder mode reflects a specific DC partition. DC partitions are also known as DC regions per CXL specification r3.1 but is not the same entity as CXL software regions.

DJ

>
> Decoder mode reflects a specific DC partition.
>
> Define the new modes to use in subsequent patches and the helper
> functions required to make the association between these new modes.
>
> Signed-off-by: Navneet Singh <navneet.singh@intel.com>
> Co-developed-by: Ira Weiny <ira.weiny@intel.com>
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> ---
> Changes for v1
> [iweiny: split out from: Add dynamic capacity cxl region support.]
> ---
> drivers/cxl/core/region.c | 4 ++++
> drivers/cxl/cxl.h | 23 +++++++++++++++++++++++
> 2 files changed, 27 insertions(+)
>
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index 1723d17f121e..ec3b8c6948e9 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -1690,6 +1690,8 @@ static bool cxl_modes_compatible(enum cxl_region_mode rmode,
> return true;
> if (rmode == CXL_REGION_PMEM && dmode == CXL_DECODER_PMEM)
> return true;
> + if (rmode == CXL_REGION_DC && cxl_decoder_mode_is_dc(dmode))
> + return true;
>
> return false;
> }
> @@ -2824,6 +2826,8 @@ cxl_decoder_to_region_mode(enum cxl_decoder_mode mode)
> return CXL_REGION_RAM;
> case CXL_DECODER_PMEM:
> return CXL_REGION_PMEM;
> + case CXL_DECODER_DC0 ... CXL_DECODER_DC7:
> + return CXL_REGION_DC;
> case CXL_DECODER_MIXED:
> default:
> return CXL_REGION_MIXED;
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index 9a0cce1e6fca..3b8935089c0c 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -365,6 +365,14 @@ enum cxl_decoder_mode {
> CXL_DECODER_NONE,
> CXL_DECODER_RAM,
> CXL_DECODER_PMEM,
> + CXL_DECODER_DC0,
> + CXL_DECODER_DC1,
> + CXL_DECODER_DC2,
> + CXL_DECODER_DC3,
> + CXL_DECODER_DC4,
> + CXL_DECODER_DC5,
> + CXL_DECODER_DC6,
> + CXL_DECODER_DC7,
> CXL_DECODER_MIXED,
> CXL_DECODER_DEAD,
> };
> @@ -375,6 +383,14 @@ static inline const char *cxl_decoder_mode_name(enum cxl_decoder_mode mode)
> [CXL_DECODER_NONE] = "none",
> [CXL_DECODER_RAM] = "ram",
> [CXL_DECODER_PMEM] = "pmem",
> + [CXL_DECODER_DC0] = "dc0",
> + [CXL_DECODER_DC1] = "dc1",
> + [CXL_DECODER_DC2] = "dc2",
> + [CXL_DECODER_DC3] = "dc3",
> + [CXL_DECODER_DC4] = "dc4",
> + [CXL_DECODER_DC5] = "dc5",
> + [CXL_DECODER_DC6] = "dc6",
> + [CXL_DECODER_DC7] = "dc7",
> [CXL_DECODER_MIXED] = "mixed",
> };
>
> @@ -383,10 +399,16 @@ static inline const char *cxl_decoder_mode_name(enum cxl_decoder_mode mode)
> return "mixed";
> }
>
> +static inline bool cxl_decoder_mode_is_dc(enum cxl_decoder_mode mode)
> +{
> + return (mode >= CXL_DECODER_DC0 && mode <= CXL_DECODER_DC7);
> +}
> +
> enum cxl_region_mode {
> CXL_REGION_NONE,
> CXL_REGION_RAM,
> CXL_REGION_PMEM,
> + CXL_REGION_DC,
> CXL_REGION_MIXED,
> };
>
> @@ -396,6 +418,7 @@ static inline const char *cxl_region_mode_name(enum cxl_region_mode mode)
> [CXL_REGION_NONE] = "none",
> [CXL_REGION_RAM] = "ram",
> [CXL_REGION_PMEM] = "pmem",
> + [CXL_REGION_DC] = "dc",
> [CXL_REGION_MIXED] = "mixed",
> };
>
>