linux-kernel - Re: [PATCH 01/26] cxl/mbox: Flag support for Dynamic Capacity Devices (DCD)

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Message-ID: <d3bcac81-35ee-4876-8f2c-6c66a7fdd960@intel.com>
Date: Tue, 26 Mar 2024 09:34:46 -0700
From: Dave Jiang <dave.jiang@...el.com>
To: ira.weiny@...el.com, Fan Ni <fan.ni@...sung.com>,
 Jonathan Cameron <Jonathan.Cameron@...wei.com>,
 Navneet Singh <navneet.singh@...el.com>
Cc: Dan Williams <dan.j.williams@...el.com>,
 Davidlohr Bueso <dave@...olabs.net>,
 Alison Schofield <alison.schofield@...el.com>,
 Vishal Verma <vishal.l.verma@...el.com>, linux-btrfs@...r.kernel.org,
 linux-cxl@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 01/26] cxl/mbox: Flag support for Dynamic Capacity Devices
 (DCD)



On 3/24/24 4:18 PM, ira.weiny@...el.com wrote:
> From: Navneet Singh <navneet.singh@...el.com>
> 
> Per the CXL 3.1 specification software must check the Command Effects
> Log (CEL) to know if a device supports dynamic capacity (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 DCD.
> 
> Signed-off-by: Navneet Singh <navneet.singh@...el.com>
> Co-developed-by: Ira Weiny <ira.weiny@...el.com>
> Signed-off-by: Ira Weiny <ira.weiny@...el.com>

Reviewed-by: Dave Jiang <dave.jiang@...el.com>

small formatting nit below

> ---
> Changes for v1
> [iweiny: update to latest master]
> [iweiny: update commit message]
> [iweiny: Based on the fix:
> 	https://lore.kernel.org/all/20230903-cxl-cel-fix-v1-1-e260c9467be3@intel.com/
> [jonathan: remove unneeded format change]
> [jonathan: don't split security code in mbox.c]
> ---
>  drivers/cxl/core/mbox.c | 33 +++++++++++++++++++++++++++++++++
>  drivers/cxl/cxlmem.h    | 15 +++++++++++++++
>  2 files changed, 48 insertions(+)
> 
> diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
> index 9adda4795eb7..ed4131c6f50b 100644
> --- a/drivers/cxl/core/mbox.c
> +++ b/drivers/cxl/core/mbox.c
> @@ -161,6 +161,34 @@ static void cxl_set_security_cmd_enabled(struct cxl_security_state *security,
>  	}
>  }
>  
> +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)

This seems misaligned.

DJ

> +{
> +	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_poison_command(u16 opcode)
>  {
>  #define CXL_MBOX_OP_POISON_CMDS 0x43
> @@ -733,6 +761,11 @@ static void cxl_walk_cel(struct cxl_memdev_state *mds, size_t size, u8 *cel)
>  			enabled++;
>  		}
>  
> +		if (cxl_is_dcd_command(opcode)) {
> +			cxl_set_dcd_cmd_enabled(mds, opcode);
> +			enabled++;
> +		}
> +
>  		dev_dbg(dev, "Opcode 0x%04x %s\n", opcode,
>  			enabled ? "enabled" : "unsupported by driver");
>  	}
> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
> index 20fb3b35e89e..79a67cff9143 100644
> --- a/drivers/cxl/cxlmem.h
> +++ b/drivers/cxl/cxlmem.h
> @@ -238,6 +238,15 @@ 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,
> @@ -454,6 +463,7 @@ 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
> @@ -481,6 +491,7 @@ 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;
> @@ -551,6 +562,10 @@ 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
>  };
>  
>