2022-08-29 22:09:01

by Adam Manzanares

Subject: [PATCH v2] cxl: Replace HDM decoder granularity magic numbers

When reviewing the CFMWS parsing code that deals with the HDM decoders,
I noticed a couple of magic numbers. This commit replaces these magic numbers
with constants defined by the CXL 3.0 specification.

v2:
- Change references to CXL 3.0 specification (David)
- CXL_DECODER_MAX_GRANULARITY_ORDER -> CXL_DECODER_MAX_ENCODED_IG (Dan)

Signed-off-by: Adam Manzanares <[email protected]>
---
drivers/cxl/cxl.h | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index f680450f0b16..3ab81ad9d2e5 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -61,6 +61,10 @@
#define CXL_HDM_DECODER0_SKIP_LOW(i) CXL_HDM_DECODER0_TL_LOW(i)
#define CXL_HDM_DECODER0_SKIP_HIGH(i) CXL_HDM_DECODER0_TL_HIGH(i)

+/* HDM decoder control register constants CXL 3.0 8.2.5.19.7 */
+#define CXL_DECODER_MIN_GRANULARITY 256
+#define CXL_DECODER_MAX_ENCODED_IG 6
+
static inline int cxl_hdm_decoder_count(u32 cap_hdr)
{
int val = FIELD_GET(CXL_HDM_DECODER_COUNT_MASK, cap_hdr);
@@ -71,9 +75,9 @@ static inline int cxl_hdm_decoder_count(u32 cap_hdr)
/* Encode defined in CXL 2.0 8.2.5.12.7 HDM Decoder Control Register */
static inline int cxl_to_granularity(u16 ig, unsigned int *val)
{
- if (ig > 6)
+ if (ig > CXL_DECODER_MAX_ENCODED_IG)
return -EINVAL;
- *val = 256 << ig;
+ *val = CXL_DECODER_MIN_GRANULARITY << ig;
return 0;
}

@@ -96,7 +100,7 @@ static inline int cxl_to_ways(u8 eniw, unsigned int *val)

static inline int granularity_to_cxl(int g, u16 *ig)
{
- if (g > SZ_16K || g < 256 || !is_power_of_2(g))
+ if (g > SZ_16K || g < CXL_DECODER_MIN_GRANULARITY || !is_power_of_2(g))
return -EINVAL;
*ig = ilog2(g) - 8;
return 0;
@@ -248,7 +252,6 @@ enum cxl_decoder_type {
*/
#define CXL_DECODER_MAX_INTERLEAVE 16

-#define CXL_DECODER_MIN_GRANULARITY 256

/**
* struct cxl_decoder - Common CXL HDM Decoder Attributes
--
2.35.1

2022-09-28 15:56:01

by Dave Jiang

Subject: Re: [PATCH v2] cxl: Replace HDM decoder granularity magic numbers

On 8/29/2022 3:03 PM, Adam Manzanares wrote:
> When reviewing the CFMWS parsing code that deals with the HDM decoders,
> I noticed a couple of magic numbers. This commit replaces these magic numbers
> with constants defined by the CXL 3.0 specification.
>
> v2:
> - Change references to CXL 3.0 specification (David)
> - CXL_DECODER_MAX_GRANULARITY_ORDER -> CXL_DECODER_MAX_ENCODED_IG (Dan)
>
> Signed-off-by: Adam Manzanares <[email protected]>

Reviewed-by: Dave Jiang <[email protected]>


> ---
> drivers/cxl/cxl.h | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index f680450f0b16..3ab81ad9d2e5 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -61,6 +61,10 @@
> #define CXL_HDM_DECODER0_SKIP_LOW(i) CXL_HDM_DECODER0_TL_LOW(i)
> #define CXL_HDM_DECODER0_SKIP_HIGH(i) CXL_HDM_DECODER0_TL_HIGH(i)
>
> +/* HDM decoder control register constants CXL 3.0 8.2.5.19.7 */
> +#define CXL_DECODER_MIN_GRANULARITY 256
> +#define CXL_DECODER_MAX_ENCODED_IG 6
> +
> static inline int cxl_hdm_decoder_count(u32 cap_hdr)
> {
> int val = FIELD_GET(CXL_HDM_DECODER_COUNT_MASK, cap_hdr);
> @@ -71,9 +75,9 @@ static inline int cxl_hdm_decoder_count(u32 cap_hdr)
> /* Encode defined in CXL 2.0 8.2.5.12.7 HDM Decoder Control Register */
> static inline int cxl_to_granularity(u16 ig, unsigned int *val)
> {
> - if (ig > 6)
> + if (ig > CXL_DECODER_MAX_ENCODED_IG)
> return -EINVAL;
> - *val = 256 << ig;
> + *val = CXL_DECODER_MIN_GRANULARITY << ig;
> return 0;
> }
>
> @@ -96,7 +100,7 @@ static inline int cxl_to_ways(u8 eniw, unsigned int *val)
>
> static inline int granularity_to_cxl(int g, u16 *ig)
> {
> - if (g > SZ_16K || g < 256 || !is_power_of_2(g))
> + if (g > SZ_16K || g < CXL_DECODER_MIN_GRANULARITY || !is_power_of_2(g))
> return -EINVAL;
> *ig = ilog2(g) - 8;
> return 0;
> @@ -248,7 +252,6 @@ enum cxl_decoder_type {
> */
> #define CXL_DECODER_MAX_INTERLEAVE 16
>
> -#define CXL_DECODER_MIN_GRANULARITY 256
>
> /**
> * struct cxl_decoder - Common CXL HDM Decoder Attributes

2022-10-21 17:58:54

by Dan Williams

Subject: RE: [PATCH v2] cxl: Replace HDM decoder granularity magic numbers

Adam Manzanares wrote:
> When reviewing the CFMWS parsing code that deals with the HDM decoders,
> I noticed a couple of magic numbers. This commit replaces these magic numbers
> with constants defined by the CXL 3.0 specification.
>
> v2:
> - Change references to CXL 3.0 specification (David)
> - CXL_DECODER_MAX_GRANULARITY_ORDER -> CXL_DECODER_MAX_ENCODED_IG (Dan)
>
> Signed-off-by: Adam Manzanares <[email protected]>

Applied for 6.2.