Re: [PATCH v4 09/28] cxl/core: Separate region mode from decoder mode

Fan Ni
2024-10-09T18:06:08Z

On Mon, Oct 07, 2024 at 06:16:15PM -0500, ira.weiny@intel.com wrote:
> From: Navneet Singh <navneet.singh@intel.com>
>
> Until now region modes and decoder modes were equivalent in that both
> modes were either PMEM or RAM. The addition of Dynamic
> Capacity partitions defines up to 8 DC partitions per device.
>
> The region mode is thus no longer equivalent to the endpoint decoder
> mode. IOW the endpoint decoders may have modes of DC0-DC7 while the
> region mode is simply DC.
>
> Define a new region mode enumeration which applies to regions separate
> from the decoder mode. Adjust the code to process these modes
> independently.
>
> There is no equal to decoder mode dead in region modes. Avoid
> constructing regions with decoders which have been flagged as dead.
>
> Suggested-by: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
> 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>
>

Reviewed-by: Fan Ni <fan.ni@samsung.com>

> ---
> Changes:
> [iweiny: rebase]
> [Jonathan: remove dead code]
> [Jonathan: clarify commit message]
> ---
> drivers/cxl/core/cdat.c | 6 ++--
> drivers/cxl/core/region.c | 75 ++++++++++++++++++++++++++++++++++-------------
> drivers/cxl/cxl.h | 26 ++++++++++++++--
> 3 files changed, 82 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/cxl/core/cdat.c b/drivers/cxl/core/cdat.c
> index 438869df241a..bd50bb655741 100644
> --- a/drivers/cxl/core/cdat.c
> +++ b/drivers/cxl/core/cdat.c
> @@ -571,17 +571,17 @@ static bool dpa_perf_contains(struct cxl_dpa_perf *perf,
> }
>
> static struct cxl_dpa_perf *cxled_get_dpa_perf(struct cxl_endpoint_decoder *cxled,
> - enum cxl_decoder_mode mode)
> + enum cxl_region_mode mode)
> {
> struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);
> struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);
> struct cxl_dpa_perf *perf;
>
> switch (mode) {
> - case CXL_DECODER_RAM:
> + case CXL_REGION_RAM:
> perf = &mds->ram_perf;
> break;
> - case CXL_DECODER_PMEM:
> + case CXL_REGION_PMEM:
> perf = &mds->pmem_perf;
> break;
> default:
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index e701e4b04032..f3a56003edc1 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -144,7 +144,7 @@ static ssize_t uuid_show(struct device *dev, struct device_attribute *attr,
> rc = down_read_interruptible(&cxl_region_rwsem);
> if (rc)
> return rc;
> - if (cxlr->mode != CXL_DECODER_PMEM)
> + if (cxlr->mode != CXL_REGION_PMEM)
> rc = sysfs_emit(buf, "\n");
> else
> rc = sysfs_emit(buf, "%pUb\n", &p->uuid);
> @@ -457,7 +457,7 @@ static umode_t cxl_region_visible(struct kobject *kobj, struct attribute *a,
> * Support tooling that expects to find a 'uuid' attribute for all
> * regions regardless of mode.
> */
> - if (a == &dev_attr_uuid.attr && cxlr->mode != CXL_DECODER_PMEM)
> + if (a == &dev_attr_uuid.attr && cxlr->mode != CXL_REGION_PMEM)
> return 0444;
> return a->mode;
> }
> @@ -620,7 +620,7 @@ static ssize_t mode_show(struct device *dev, struct device_attribute *attr,
> {
> struct cxl_region *cxlr = to_cxl_region(dev);
>
> - return sysfs_emit(buf, "%s\n", cxl_decoder_mode_name(cxlr->mode));
> + return sysfs_emit(buf, "%s\n", cxl_region_mode_name(cxlr->mode));
> }
> static DEVICE_ATTR_RO(mode);
>
> @@ -646,7 +646,7 @@ static int alloc_hpa(struct cxl_region *cxlr, resource_size_t size)
>
> /* ways, granularity and uuid (if PMEM) need to be set before HPA */
> if (!p->interleave_ways || !p->interleave_granularity ||
> - (cxlr->mode == CXL_DECODER_PMEM && uuid_is_null(&p->uuid)))
> + (cxlr->mode == CXL_REGION_PMEM && uuid_is_null(&p->uuid)))
> return -ENXIO;
>
> div64_u64_rem(size, (u64)SZ_256M * p->interleave_ways, &remainder);
> @@ -1863,6 +1863,17 @@ static int cxl_region_sort_targets(struct cxl_region *cxlr)
> return rc;
> }
>
> +static bool cxl_modes_compatible(enum cxl_region_mode rmode,
> + enum cxl_decoder_mode dmode)
> +{
> + if (rmode == CXL_REGION_RAM && dmode == CXL_DECODER_RAM)
> + return true;
> + if (rmode == CXL_REGION_PMEM && dmode == CXL_DECODER_PMEM)
> + return true;
> +
> + return false;
> +}
> +
> static int cxl_region_attach(struct cxl_region *cxlr,
> struct cxl_endpoint_decoder *cxled, int pos)
> {
> @@ -1882,9 +1893,11 @@ static int cxl_region_attach(struct cxl_region *cxlr,
> return rc;
> }
>
> - if (cxled->mode != cxlr->mode) {
> - dev_dbg(&cxlr->dev, "%s region mode: %d mismatch: %d\n",
> - dev_name(&cxled->cxld.dev), cxlr->mode, cxled->mode);
> + if (!cxl_modes_compatible(cxlr->mode, cxled->mode)) {
> + dev_dbg(&cxlr->dev, "%s region mode: %s mismatch decoder: %s\n",
> + dev_name(&cxled->cxld.dev),
> + cxl_region_mode_name(cxlr->mode),
> + cxl_decoder_mode_name(cxled->mode));
> return -EINVAL;
> }
>
> @@ -2446,7 +2459,7 @@ static int cxl_region_calculate_adistance(struct notifier_block *nb,
> * devm_cxl_add_region - Adds a region to a decoder
> * @cxlrd: root decoder
> * @id: memregion id to create, or memregion_free() on failure
> - * @mode: mode for the endpoint decoders of this region
> + * @mode: mode of this region
> * @type: select whether this is an expander or accelerator (type-2 or type-3)
> *
> * This is the second step of region initialization. Regions exist within an
> @@ -2457,7 +2470,7 @@ static int cxl_region_calculate_adistance(struct notifier_block *nb,
> */
> static struct cxl_region *devm_cxl_add_region(struct cxl_root_decoder *cxlrd,
> int id,
> - enum cxl_decoder_mode mode,
> + enum cxl_region_mode mode,
> enum cxl_decoder_type type)
> {
> struct cxl_port *port = to_cxl_port(cxlrd->cxlsd.cxld.dev.parent);
> @@ -2511,16 +2524,17 @@ static ssize_t create_ram_region_show(struct device *dev,
> }
>
> static struct cxl_region *__create_region(struct cxl_root_decoder *cxlrd,
> - enum cxl_decoder_mode mode, int id)
> + enum cxl_region_mode mode, int id)
> {
> int rc;
>
> switch (mode) {
> - case CXL_DECODER_RAM:
> - case CXL_DECODER_PMEM:
> + case CXL_REGION_RAM:
> + case CXL_REGION_PMEM:
> break;
> default:
> - dev_err(&cxlrd->cxlsd.cxld.dev, "unsupported mode %d\n", mode);
> + dev_err(&cxlrd->cxlsd.cxld.dev, "unsupported mode %s\n",
> + cxl_region_mode_name(mode));
> return ERR_PTR(-EINVAL);
> }
>
> @@ -2548,7 +2562,7 @@ static ssize_t create_pmem_region_store(struct device *dev,
> if (rc != 1)
> return -EINVAL;
>
> - cxlr = __create_region(cxlrd, CXL_DECODER_PMEM, id);
> + cxlr = __create_region(cxlrd, CXL_REGION_PMEM, id);
> if (IS_ERR(cxlr))
> return PTR_ERR(cxlr);
>
> @@ -2568,7 +2582,7 @@ static ssize_t create_ram_region_store(struct device *dev,
> if (rc != 1)
> return -EINVAL;
>
> - cxlr = __create_region(cxlrd, CXL_DECODER_RAM, id);
> + cxlr = __create_region(cxlrd, CXL_REGION_RAM, id);
> if (IS_ERR(cxlr))
> return PTR_ERR(cxlr);
>
> @@ -3215,6 +3229,22 @@ static int match_region_by_range(struct device *dev, void *data)
> return rc;
> }
>
> +static enum cxl_region_mode
> +cxl_decoder_to_region_mode(enum cxl_decoder_mode mode)
> +{
> + switch (mode) {
> + case CXL_DECODER_NONE:
> + return CXL_REGION_NONE;
> + case CXL_DECODER_RAM:
> + return CXL_REGION_RAM;
> + case CXL_DECODER_PMEM:
> + return CXL_REGION_PMEM;
> + case CXL_DECODER_MIXED:
> + default:
> + return CXL_REGION_MIXED;
> + }
> +}
> +
> /* Establish an empty region covering the given HPA range */
> static struct cxl_region *construct_region(struct cxl_root_decoder *cxlrd,
> struct cxl_endpoint_decoder *cxled)
> @@ -3223,12 +3253,17 @@ static struct cxl_region *construct_region(struct cxl_root_decoder *cxlrd,
> struct cxl_port *port = cxlrd_to_port(cxlrd);
> struct range *hpa = &cxled->cxld.hpa_range;
> struct cxl_region_params *p;
> + enum cxl_region_mode mode;
> struct cxl_region *cxlr;
> struct resource *res;
> int rc;
>
> + if (cxled->mode == CXL_DECODER_DEAD)
> + return ERR_PTR(-EINVAL);
> +
> + mode = cxl_decoder_to_region_mode(cxled->mode);
> do {
> - cxlr = __create_region(cxlrd, cxled->mode,
> + cxlr = __create_region(cxlrd, mode,
> atomic_read(&cxlrd->region_id));
> } while (IS_ERR(cxlr) && PTR_ERR(cxlr) == -EBUSY);
>
> @@ -3431,9 +3466,9 @@ static int cxl_region_probe(struct device *dev)
> return rc;
>
> switch (cxlr->mode) {
> - case CXL_DECODER_PMEM:
> + case CXL_REGION_PMEM:
> return devm_cxl_add_pmem_region(cxlr);
> - case CXL_DECODER_RAM:
> + case CXL_REGION_RAM:
> /*
> * The region can not be manged by CXL if any portion of
> * it is already online as 'System RAM'
> @@ -3445,8 +3480,8 @@ static int cxl_region_probe(struct device *dev)
> return 0;
> return devm_cxl_add_dax_region(cxlr);
> default:
> - dev_dbg(&cxlr->dev, "unsupported region mode: %d\n",
> - cxlr->mode);
> + dev_dbg(&cxlr->dev, "unsupported region mode: %s\n",
> + cxl_region_mode_name(cxlr->mode));
> return -ENXIO;
> }
> }
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index 0d8b810a51f0..5d74eb4ffab3 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -388,6 +388,27 @@ static inline const char *cxl_decoder_mode_name(enum cxl_decoder_mode mode)
> return "mixed";
> }
>
> +enum cxl_region_mode {
> + CXL_REGION_NONE,
> + CXL_REGION_RAM,
> + CXL_REGION_PMEM,
> + CXL_REGION_MIXED,
> +};
> +
> +static inline const char *cxl_region_mode_name(enum cxl_region_mode mode)
> +{
> + static const char * const names[] = {
> + [CXL_REGION_NONE] = "none",
> + [CXL_REGION_RAM] = "ram",
> + [CXL_REGION_PMEM] = "pmem",
> + [CXL_REGION_MIXED] = "mixed",
> + };
> +
> + if (mode >= CXL_REGION_NONE && mode <= CXL_REGION_MIXED)
> + return names[mode];
> + return "mixed";
> +}
> +
> /*
> * Track whether this decoder is reserved for region autodiscovery, or
> * free for userspace provisioning.
> @@ -515,7 +536,8 @@ struct cxl_region_params {
> * struct cxl_region - CXL region
> * @dev: This region's device
> * @id: This region's id. Id is globally unique across all regions
> - * @mode: Endpoint decoder allocation / access mode
> + * @mode: Region mode which defines which endpoint decoder modes the region is
> + * compatible with
> * @type: Endpoint decoder target type
> * @cxl_nvb: nvdimm bridge for coordinating @cxlr_pmem setup / shutdown
> * @cxlr_pmem: (for pmem regions) cached copy of the nvdimm bridge
> @@ -528,7 +550,7 @@ struct cxl_region_params {
> struct cxl_region {
> struct device dev;
> int id;
> - enum cxl_decoder_mode mode;
> + enum cxl_region_mode mode;
> enum cxl_decoder_type type;
> struct cxl_nvdimm_bridge *cxl_nvb;
> struct cxl_pmem_region *cxlr_pmem;
>
> --
> 2.46.0
>

--
Fan Ni