Re: [PATCH v3 02/20] cxl: add capabilities field to cxl_dev_state and cxl_port

Alejandro Lucero Palau
2024-09-16T08:37:39Z

On 9/11/24 23:17, Dave Jiang wrote:
>
> On 9/7/24 1:18 AM, alejandro.lucero-palau@amd.com wrote:
>> From: Alejandro Lucero <alucerop@amd.com>
>>
>> Type2 devices have some Type3 functionalities as optional like an mbox
>> or an hdm decoder, and CXL core needs a way to know what an CXL accelerator
>> implements.
>>
>> Add a new field for keeping device capabilities as discovered during
>> initialization.
>>
>> Add same field to cxl_port which for an endpoint will use those
>> capabilities discovered previously, and which will be initialized when
>> calling cxl_port_setup_regs for no endpoints.
> I don't quite understand what you are trying to say here.

I guess you mean the last paragraph, don't you?

If so, the point is the cxl_setup_regs or the register discovery is also
being used from the cxl port code, I think for CXL switches initialization.

>> Signed-off-by: Alejandro Lucero <alucerop@amd.com>
>> ---
>> drivers/cxl/core/port.c | 9 +++++----
>> drivers/cxl/core/regs.c | 20 +++++++++++++-------
>> drivers/cxl/cxl.h | 8 +++++---
>> drivers/cxl/cxlmem.h | 2 ++
>> drivers/cxl/pci.c | 9 +++++----
>> include/linux/cxl/cxl.h | 30 ++++++++++++++++++++++++++++++
>> 6 files changed, 60 insertions(+), 18 deletions(-)
>>
>> diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
>> index 1d5007e3795a..39b20ddd0296 100644
>> --- a/drivers/cxl/core/port.c
>> +++ b/drivers/cxl/core/port.c
>> @@ -749,7 +749,7 @@ static struct cxl_port *cxl_port_alloc(struct device *uport_dev,
>> }
>>
>> static int cxl_setup_comp_regs(struct device *host, struct cxl_register_map *map,
>> - resource_size_t component_reg_phys)
>> + resource_size_t component_reg_phys, u32 *caps)
>> {
>> *map = (struct cxl_register_map) {
>> .host = host,
>> @@ -763,7 +763,7 @@ static int cxl_setup_comp_regs(struct device *host, struct cxl_register_map *map
>> map->reg_type = CXL_REGLOC_RBI_COMPONENT;
>> map->max_size = CXL_COMPONENT_REG_BLOCK_SIZE;
>>
>> - return cxl_setup_regs(map);
>> + return cxl_setup_regs(map, caps);
>> }
>>
>> static int cxl_port_setup_regs(struct cxl_port *port,
>> @@ -772,7 +772,7 @@ static int cxl_port_setup_regs(struct cxl_port *port,
>> if (dev_is_platform(port->uport_dev))
>> return 0;
>> return cxl_setup_comp_regs(&port->dev, &port->reg_map,
>> - component_reg_phys);
>> + component_reg_phys, &port->capabilities);
>> }
>>
>> static int cxl_dport_setup_regs(struct device *host, struct cxl_dport *dport,
>> @@ -789,7 +789,7 @@ static int cxl_dport_setup_regs(struct device *host, struct cxl_dport *dport,
>> * NULL.
>> */
>> rc = cxl_setup_comp_regs(dport->dport_dev, &dport->reg_map,
>> - component_reg_phys);
>> + component_reg_phys, &dport->port->capabilities);
>> dport->reg_map.host = host;
>> return rc;
>> }
>> @@ -858,6 +858,7 @@ static struct cxl_port *__devm_cxl_add_port(struct device *host,
>> port->reg_map = cxlds->reg_map;
>> port->reg_map.host = &port->dev;
>> cxlmd->endpoint = port;
>> + port->capabilities = cxlds->capabilities;
>> } else if (parent_dport) {
>> rc = dev_set_name(dev, "port%d", port->id);
>> if (rc)
>> diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c
>> index e1082e749c69..8b8abcadcb93 100644
>> --- a/drivers/cxl/core/regs.c
>> +++ b/drivers/cxl/core/regs.c
>> @@ -1,6 +1,7 @@
>> // SPDX-License-Identifier: GPL-2.0-only
>> /* Copyright(c) 2020 Intel Corporation. */
>> #include <linux/io-64-nonatomic-lo-hi.h>
>> +#include <linux/cxl/cxl.h>
>> #include <linux/device.h>
>> #include <linux/slab.h>
>> #include <linux/pci.h>
>> @@ -36,7 +37,7 @@
>> * Probe for component register information and return it in map object.
>> */
>> void cxl_probe_component_regs(struct device *dev, void __iomem *base,
>> - struct cxl_component_reg_map *map)
>> + struct cxl_component_reg_map *map, u32 *caps)
>> {
>> int cap, cap_count;
>> u32 cap_array;
>> @@ -84,6 +85,7 @@ void cxl_probe_component_regs(struct device *dev, void __iomem *base,
>> decoder_cnt = cxl_hdm_decoder_count(hdr);
>> length = 0x20 * decoder_cnt + 0x10;
>> rmap = &map->hdm_decoder;
>> + *caps |= BIT(CXL_DEV_CAP_HDM);
>> break;
>> }
>> case CXL_CM_CAP_CAP_ID_RAS:
>> @@ -91,6 +93,7 @@ void cxl_probe_component_regs(struct device *dev, void __iomem *base,
>> offset);
>> length = CXL_RAS_CAPABILITY_LENGTH;
>> rmap = &map->ras;
>> + *caps |= BIT(CXL_DEV_CAP_RAS);
>> break;
>> default:
>> dev_dbg(dev, "Unknown CM cap ID: %d (0x%x)\n", cap_id,
>> @@ -117,7 +120,7 @@ EXPORT_SYMBOL_NS_GPL(cxl_probe_component_regs, CXL);
>> * Probe for device register information and return it in map object.
>> */
>> void cxl_probe_device_regs(struct device *dev, void __iomem *base,
>> - struct cxl_device_reg_map *map)
>> + struct cxl_device_reg_map *map, u32 *caps)
>> {
>> int cap, cap_count;
>> u64 cap_array;
>> @@ -146,10 +149,12 @@ void cxl_probe_device_regs(struct device *dev, void __iomem *base,
>> case CXLDEV_CAP_CAP_ID_DEVICE_STATUS:
>> dev_dbg(dev, "found Status capability (0x%x)\n", offset);
>> rmap = &map->status;
>> + *caps |= BIT(CXL_DEV_CAP_DEV_STATUS);
>> break;
>> case CXLDEV_CAP_CAP_ID_PRIMARY_MAILBOX:
>> dev_dbg(dev, "found Mailbox capability (0x%x)\n", offset);
>> rmap = &map->mbox;
>> + *caps |= BIT(CXL_DEV_CAP_MAILBOX_PRIMARY);
>> break;
>> case CXLDEV_CAP_CAP_ID_SECONDARY_MAILBOX:
>> dev_dbg(dev, "found Secondary Mailbox capability (0x%x)\n", offset);
>> @@ -157,6 +162,7 @@ void cxl_probe_device_regs(struct device *dev, void __iomem *base,
>> case CXLDEV_CAP_CAP_ID_MEMDEV:
>> dev_dbg(dev, "found Memory Device capability (0x%x)\n", offset);
>> rmap = &map->memdev;
>> + *caps |= BIT(CXL_DEV_CAP_MEMDEV);
>> break;
>> default:
>> if (cap_id >= 0x8000)
>> @@ -421,7 +427,7 @@ static void cxl_unmap_regblock(struct cxl_register_map *map)
>> map->base = NULL;
>> }
>>
>> -static int cxl_probe_regs(struct cxl_register_map *map)
>> +static int cxl_probe_regs(struct cxl_register_map *map, u32 *caps)
>> {
>> struct cxl_component_reg_map *comp_map;
>> struct cxl_device_reg_map *dev_map;
>> @@ -431,12 +437,12 @@ static int cxl_probe_regs(struct cxl_register_map *map)
>> switch (map->reg_type) {
>> case CXL_REGLOC_RBI_COMPONENT:
>> comp_map = &map->component_map;
>> - cxl_probe_component_regs(host, base, comp_map);
>> + cxl_probe_component_regs(host, base, comp_map, caps);
>> dev_dbg(host, "Set up component registers\n");
>> break;
>> case CXL_REGLOC_RBI_MEMDEV:
>> dev_map = &map->device_map;
>> - cxl_probe_device_regs(host, base, dev_map);
>> + cxl_probe_device_regs(host, base, dev_map, caps);
>> if (!dev_map->status.valid || !dev_map->mbox.valid ||
>> !dev_map->memdev.valid) {
>> dev_err(host, "registers not found: %s%s%s\n",
>> @@ -455,7 +461,7 @@ static int cxl_probe_regs(struct cxl_register_map *map)
>> return 0;
>> }
>>
>> -int cxl_setup_regs(struct cxl_register_map *map)
>> +int cxl_setup_regs(struct cxl_register_map *map, u32 *caps)
>> {
>> int rc;
>>
>> @@ -463,7 +469,7 @@ int cxl_setup_regs(struct cxl_register_map *map)
>> if (rc)
>> return rc;
>>
>> - rc = cxl_probe_regs(map);
>> + rc = cxl_probe_regs(map, caps);
>> cxl_unmap_regblock(map);
>>
>> return rc;
>> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
>> index 9afb407d438f..07c153aa3d77 100644
>> --- a/drivers/cxl/cxl.h
>> +++ b/drivers/cxl/cxl.h
>> @@ -284,9 +284,9 @@ struct cxl_register_map {
>> };
>>
>> void cxl_probe_component_regs(struct device *dev, void __iomem *base,
>> - struct cxl_component_reg_map *map);
>> + struct cxl_component_reg_map *map, u32 *caps);
>> void cxl_probe_device_regs(struct device *dev, void __iomem *base,
>> - struct cxl_device_reg_map *map);
>> + struct cxl_device_reg_map *map, u32 *caps);
>> int cxl_map_component_regs(const struct cxl_register_map *map,
>> struct cxl_component_regs *regs,
>> unsigned long map_mask);
>> @@ -300,7 +300,7 @@ int cxl_find_regblock_instance(struct pci_dev *pdev, enum cxl_regloc_type type,
>> struct cxl_register_map *map, int index);
>> int cxl_find_regblock(struct pci_dev *pdev, enum cxl_regloc_type type,
>> struct cxl_register_map *map);
>> -int cxl_setup_regs(struct cxl_register_map *map);
>> +int cxl_setup_regs(struct cxl_register_map *map, u32 *caps);
>> struct cxl_dport;
>> resource_size_t cxl_rcd_component_reg_phys(struct device *dev,
>> struct cxl_dport *dport);
>> @@ -600,6 +600,7 @@ struct cxl_dax_region {
>> * @cdat: Cached CDAT data
>> * @cdat_available: Should a CDAT attribute be available in sysfs
>> * @pci_latency: Upstream latency in picoseconds
>> + * @capabilities: those capabilities as defined in device mapped registers
>> */
>> struct cxl_port {
>> struct device dev;
>> @@ -623,6 +624,7 @@ struct cxl_port {
>> } cdat;
>> bool cdat_available;
>> long pci_latency;
>> + u32 capabilities;
>> };
>>
>> /**
>> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
>> index afb53d058d62..37c043100300 100644
>> --- a/drivers/cxl/cxlmem.h
>> +++ b/drivers/cxl/cxlmem.h
>> @@ -424,6 +424,7 @@ struct cxl_dpa_perf {
>> * @ram_res: Active Volatile memory capacity configuration
>> * @serial: PCIe Device Serial Number
>> * @type: Generic Memory Class device or Vendor Specific Memory device
>> + * @capabilities: those capabilities as defined in device mapped registers
>> */
>> struct cxl_dev_state {
>> struct device *dev;
>> @@ -438,6 +439,7 @@ struct cxl_dev_state {
>> struct resource ram_res;
>> u64 serial;
>> enum cxl_devtype type;
>> + u32 capabilities;
>> };
>>
>> /**
>> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
>> index 742a7b2a1be5..58f325019886 100644
>> --- a/drivers/cxl/pci.c
>> +++ b/drivers/cxl/pci.c
>> @@ -503,7 +503,7 @@ static int cxl_rcrb_get_comp_regs(struct pci_dev *pdev,
>> }
>>
>> static int cxl_pci_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type,
>> - struct cxl_register_map *map)
>> + struct cxl_register_map *map, u32 *caps)
>> {
>> int rc;
>>
>> @@ -520,7 +520,7 @@ static int cxl_pci_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type,
>> if (rc)
>> return rc;
>>
>> - return cxl_setup_regs(map);
>> + return cxl_setup_regs(map, caps);
>> }
>>
>> static int cxl_pci_ras_unmask(struct pci_dev *pdev)
>> @@ -827,7 +827,8 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>> else
>> cxl_set_dvsec(cxlds, dvsec);
>>
>> - rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_MEMDEV, &map);
>> + rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_MEMDEV, &map,
>> + &cxlds->capabilities);
>> if (rc)
>> return rc;
>>
>> @@ -840,7 +841,7 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>> * still be useful for management functions so don't return an error.
>> */
>> rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_COMPONENT,
>> - &cxlds->reg_map);
>> + &cxlds->reg_map, &cxlds->capabilities);
>> if (rc)
>> dev_warn(&pdev->dev, "No component registers (%d)\n", rc);
>> else if (!cxlds->reg_map.component_map.ras.valid)
>> diff --git a/include/linux/cxl/cxl.h b/include/linux/cxl/cxl.h
>> index e78eefa82123..930b1b9c1d6a 100644
>> --- a/include/linux/cxl/cxl.h
>> +++ b/include/linux/cxl/cxl.h
>> @@ -12,6 +12,36 @@ enum cxl_resource {
>> CXL_ACCEL_RES_PMEM,
>> };
>>
>> +/* Capabilities as defined for:
>> + *
>> + * Component Registers (Table 8-22 CXL 3.0 specification)
>> + * Device Registers (8.2.8.2.1 CXL 3.0 specification)
> Should just use 3.1 since that's the latest spec.

Ok.

>> + */
>> +
>> +enum cxl_dev_cap {
>> + /* capabilities from Component Registers */
>> + CXL_DEV_CAP_RAS,
>> + CXL_DEV_CAP_SEC,
>> + CXL_DEV_CAP_LINK,
>> + CXL_DEV_CAP_HDM,
>> + CXL_DEV_CAP_SEC_EXT,
>> + CXL_DEV_CAP_IDE,
>> + CXL_DEV_CAP_SNOOP_FILTER,
>> + CXL_DEV_CAP_TIMEOUT_AND_ISOLATION,
>> + CXL_DEV_CAP_CACHEMEM_EXT,
>> + CXL_DEV_CAP_BI_ROUTE_TABLE,
>> + CXL_DEV_CAP_BI_DECODER,
>> + CXL_DEV_CAP_CACHEID_ROUTE_TABLE,
>> + CXL_DEV_CAP_CACHEID_DECODER,
>> + CXL_DEV_CAP_HDM_EXT,
>> + CXL_DEV_CAP_METADATA_EXT,
>> + /* capabilities from Device Registers */
>> + CXL_DEV_CAP_DEV_STATUS,
>> + CXL_DEV_CAP_MAILBOX_PRIMARY,
>> + CXL_DEV_CAP_MAILBOX_SECONDARY,
> Does the OS ever uses the SECONDARY mailbox?

I have no idea. I'm just listing all the potential capabilities here as
you can see for things like BI or SNOOP.

Should I just add those referenced by code?

>> + CXL_DEV_CAP_MEMDEV,
>> +};
>> +
>> struct cxl_dev_state *cxl_accel_state_create(struct device *dev);
>>
>> void cxl_set_dvsec(struct cxl_dev_state *cxlds, u16 dvsec);