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

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Message-Id: <20230604-dcd-type2-upstream-v2-2-f740c47e7916@intel.com>
Date:   Mon, 28 Aug 2023 22:20:53 -0700
From:   Ira Weiny <ira.weiny@...el.com>
To:     Dan Williams <dan.j.williams@...el.com>
Cc:     Navneet Singh <navneet.singh@...el.com>,
        Fan Ni <fan.ni@...sung.com>,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        Davidlohr Bueso <dave@...olabs.net>,
        Dave Jiang <dave.jiang@...el.com>,
        Alison Schofield <alison.schofield@...el.com>,
        Vishal Verma <vishal.l.verma@...el.com>,
        Ira Weiny <ira.weiny@...el.com>, linux-cxl@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH RFC v2 02/18] cxl/mbox: Flag support for Dynamic Capacity
 Devices (DCD)

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@...el.com>
Signed-off-by: Navneet Singh <navneet.singh@...el.com>
Signed-off-by: Ira Weiny <ira.weiny@...el.com>

---
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