Re: [PATCH RFC v2 02/18] cxl/mbox: Flag support for Dynamic Capacity Devices (DCD)

From: Fan Ni
Date: Tue Aug 29 2023 - 17:51:07 EST


On Mon, Aug 28, 2023 at 10:20:53PM -0700, Ira Weiny wrote:
> Per the CXL 3.0 specification software must check the Command Effects
> Log (CEL) to know if a device supports DC. If the device does support
> DC the specifics of the DC Regions (0-7) are read through the mailbox.
>
> Flag DC Device (DCD) commands in a device if they are supported.
> Subsequent patches will key off these bits to configure a DCD.
>
> Co-developed-by: Navneet Singh <navneet.singh@xxxxxxxxx>
> Signed-off-by: Navneet Singh <navneet.singh@xxxxxxxxx>
> Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
>

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

> ---
> Changes for v2
> [iweiny: new patch]
> ---
> drivers/cxl/core/mbox.c | 38 +++++++++++++++++++++++++++++++++++---
> drivers/cxl/cxlmem.h | 15 +++++++++++++++
> 2 files changed, 50 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
> index f052d5f174ee..554ec97a7c39 100644
> --- a/drivers/cxl/core/mbox.c
> +++ b/drivers/cxl/core/mbox.c
> @@ -111,6 +111,34 @@ static u8 security_command_sets[] = {
> 0x46, /* Security Passthrough */
> };
>
> +static bool cxl_is_dcd_command(u16 opcode)
> +{
> +#define CXL_MBOX_OP_DCD_CMDS 0x48
> +
> + return (opcode >> 8) == CXL_MBOX_OP_DCD_CMDS;
> +}
> +
> +static void cxl_set_dcd_cmd_enabled(struct cxl_memdev_state *mds,
> + u16 opcode)
> +{
> + switch (opcode) {
> + case CXL_MBOX_OP_GET_DC_CONFIG:
> + set_bit(CXL_DCD_ENABLED_GET_CONFIG, mds->dcd_cmds);
> + break;
> + case CXL_MBOX_OP_GET_DC_EXTENT_LIST:
> + set_bit(CXL_DCD_ENABLED_GET_EXTENT_LIST, mds->dcd_cmds);
> + break;
> + case CXL_MBOX_OP_ADD_DC_RESPONSE:
> + set_bit(CXL_DCD_ENABLED_ADD_RESPONSE, mds->dcd_cmds);
> + break;
> + case CXL_MBOX_OP_RELEASE_DC:
> + set_bit(CXL_DCD_ENABLED_RELEASE, mds->dcd_cmds);
> + break;
> + default:
> + break;
> + }
> +}
> +
> static bool cxl_is_security_command(u16 opcode)
> {
> int i;
> @@ -677,9 +705,10 @@ static void cxl_walk_cel(struct cxl_memdev_state *mds, size_t size, u8 *cel)
> u16 opcode = le16_to_cpu(cel_entry[i].opcode);
> struct cxl_mem_command *cmd = cxl_mem_find_command(opcode);
>
> - if (!cmd && !cxl_is_poison_command(opcode)) {
> - dev_dbg(dev,
> - "Opcode 0x%04x unsupported by driver\n", opcode);
> + if (!cmd && !cxl_is_poison_command(opcode) &&
> + !cxl_is_dcd_command(opcode)) {
> + dev_dbg(dev, "Opcode 0x%04x unsupported by driver\n",
> + opcode);
> continue;
> }
>
> @@ -689,6 +718,9 @@ static void cxl_walk_cel(struct cxl_memdev_state *mds, size_t size, u8 *cel)
> if (cxl_is_poison_command(opcode))
> cxl_set_poison_cmd_enabled(&mds->poison, opcode);
>
> + if (cxl_is_dcd_command(opcode))
> + cxl_set_dcd_cmd_enabled(mds, opcode);
> +
> dev_dbg(dev, "Opcode 0x%04x enabled\n", opcode);
> }
> }
> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
> index adfba72445fc..5f2e65204bf9 100644
> --- a/drivers/cxl/cxlmem.h
> +++ b/drivers/cxl/cxlmem.h
> @@ -247,6 +247,15 @@ struct cxl_event_state {
> struct mutex log_lock;
> };
>
> +/* Device enabled DCD commands */
> +enum dcd_cmd_enabled_bits {
> + CXL_DCD_ENABLED_GET_CONFIG,
> + CXL_DCD_ENABLED_GET_EXTENT_LIST,
> + CXL_DCD_ENABLED_ADD_RESPONSE,
> + CXL_DCD_ENABLED_RELEASE,
> + CXL_DCD_ENABLED_MAX
> +};
> +
> /* Device enabled poison commands */
> enum poison_cmd_enabled_bits {
> CXL_POISON_ENABLED_LIST,
> @@ -436,6 +445,7 @@ struct cxl_dev_state {
> * (CXL 2.0 8.2.9.5.1.1 Identify Memory Device)
> * @mbox_mutex: Mutex to synchronize mailbox access.
> * @firmware_version: Firmware version for the memory device.
> + * @dcd_cmds: List of DCD commands implemented by memory device
> * @enabled_cmds: Hardware commands found enabled in CEL.
> * @exclusive_cmds: Commands that are kernel-internal only
> * @total_bytes: sum of all possible capacities
> @@ -460,6 +470,7 @@ struct cxl_memdev_state {
> size_t lsa_size;
> struct mutex mbox_mutex; /* Protects device mailbox and firmware */
> char firmware_version[0x10];
> + DECLARE_BITMAP(dcd_cmds, CXL_DCD_ENABLED_MAX);
> DECLARE_BITMAP(enabled_cmds, CXL_MEM_COMMAND_ID_MAX);
> DECLARE_BITMAP(exclusive_cmds, CXL_MEM_COMMAND_ID_MAX);
> u64 total_bytes;
> @@ -525,6 +536,10 @@ enum cxl_opcode {
> CXL_MBOX_OP_UNLOCK = 0x4503,
> CXL_MBOX_OP_FREEZE_SECURITY = 0x4504,
> CXL_MBOX_OP_PASSPHRASE_SECURE_ERASE = 0x4505,
> + CXL_MBOX_OP_GET_DC_CONFIG = 0x4800,
> + CXL_MBOX_OP_GET_DC_EXTENT_LIST = 0x4801,
> + CXL_MBOX_OP_ADD_DC_RESPONSE = 0x4802,
> + CXL_MBOX_OP_RELEASE_DC = 0x4803,
> CXL_MBOX_OP_MAX = 0x10000
> };
>
>
> --
> 2.41.0
>