[PATCH 2/8] cxl/mem: Introduce 'struct cxl_regs'
From: Dan Williams
Date: Wed Mar 24 2021 - 17:31:38 EST
In preparation for common register mapping facility, introduce a generic
container, 'struct cxl_regs', for CXL device register and later
component register block base pointers. Some CXL device types implement
both.
Reviewed-by: Ben Widawsky <ben.widawsky@xxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
drivers/cxl/cxl.h | 33 +++++++++++++++++++++++++++++++++
drivers/cxl/mem.c | 44 ++++++++++++++++++++++++--------------------
drivers/cxl/mem.h | 13 +++++--------
3 files changed, 62 insertions(+), 28 deletions(-)
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 2e3bdacb32e7..37325e504fb7 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -34,5 +34,38 @@
#define CXLDEV_MBOX_BG_CMD_STATUS_OFFSET 0x18
#define CXLDEV_MBOX_PAYLOAD_OFFSET 0x20
+/* See note for 'struct cxl_regs' for the rationale of this organization */
+#define CXL_DEVICE_REGS() \
+ void __iomem *status; \
+ void __iomem *mbox; \
+ void __iomem *memdev
+
+/**
+ * struct cxl_device_regs - Common container of CXL Device register
+ * block base pointers
+ * @status: CXL 2.0 8.2.8.3 Device Status Registers
+ * @mbox: CXL 2.0 8.2.8.4 Mailbox Registers
+ * @memdev: CXL 2.0 8.2.8.5 Memory Device Registers
+ */
+struct cxl_device_regs {
+ CXL_DEVICE_REGS();
+};
+
+/*
+ * Note, the anonymous union organization allows for per
+ * register-block-type helper routines, without requiring block-type
+ * agnostic code to include the prefix. I.e.
+ * cxl_setup_device_regs(&cxlm->regs.dev) vs readl(cxlm->regs.mbox).
+ * The specificity reads naturally from left-to-right.
+ */
+struct cxl_regs {
+ union {
+ struct {
+ CXL_DEVICE_REGS();
+ };
+ struct cxl_device_regs device_regs;
+ };
+};
+
extern struct bus_type cxl_bus_type;
#endif /* __CXL_H__ */
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index 45871ef65152..6951243d128e 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -31,7 +31,7 @@
*/
#define cxl_doorbell_busy(cxlm) \
- (readl((cxlm)->mbox_regs + CXLDEV_MBOX_CTRL_OFFSET) & \
+ (readl((cxlm)->regs.mbox + CXLDEV_MBOX_CTRL_OFFSET) & \
CXLDEV_MBOX_CTRL_DOORBELL)
/* CXL 2.0 - 8.2.8.4 */
@@ -271,7 +271,7 @@ static void cxl_mem_mbox_timeout(struct cxl_mem *cxlm,
static int __cxl_mem_mbox_send_cmd(struct cxl_mem *cxlm,
struct mbox_cmd *mbox_cmd)
{
- void __iomem *payload = cxlm->mbox_regs + CXLDEV_MBOX_PAYLOAD_OFFSET;
+ void __iomem *payload = cxlm->regs.mbox + CXLDEV_MBOX_PAYLOAD_OFFSET;
u64 cmd_reg, status_reg;
size_t out_len;
int rc;
@@ -314,12 +314,12 @@ static int __cxl_mem_mbox_send_cmd(struct cxl_mem *cxlm,
}
/* #2, #3 */
- writeq(cmd_reg, cxlm->mbox_regs + CXLDEV_MBOX_CMD_OFFSET);
+ writeq(cmd_reg, cxlm->regs.mbox + CXLDEV_MBOX_CMD_OFFSET);
/* #4 */
dev_dbg(&cxlm->pdev->dev, "Sending command\n");
writel(CXLDEV_MBOX_CTRL_DOORBELL,
- cxlm->mbox_regs + CXLDEV_MBOX_CTRL_OFFSET);
+ cxlm->regs.mbox + CXLDEV_MBOX_CTRL_OFFSET);
/* #5 */
rc = cxl_mem_wait_for_doorbell(cxlm);
@@ -329,7 +329,7 @@ static int __cxl_mem_mbox_send_cmd(struct cxl_mem *cxlm,
}
/* #6 */
- status_reg = readq(cxlm->mbox_regs + CXLDEV_MBOX_STATUS_OFFSET);
+ status_reg = readq(cxlm->regs.mbox + CXLDEV_MBOX_STATUS_OFFSET);
mbox_cmd->return_code =
FIELD_GET(CXLDEV_MBOX_STATUS_RET_CODE_MASK, status_reg);
@@ -339,7 +339,7 @@ static int __cxl_mem_mbox_send_cmd(struct cxl_mem *cxlm,
}
/* #7 */
- cmd_reg = readq(cxlm->mbox_regs + CXLDEV_MBOX_CMD_OFFSET);
+ cmd_reg = readq(cxlm->regs.mbox + CXLDEV_MBOX_CMD_OFFSET);
out_len = FIELD_GET(CXLDEV_MBOX_CMD_PAYLOAD_LENGTH_MASK, cmd_reg);
/* #8 */
@@ -400,7 +400,7 @@ static int cxl_mem_mbox_get(struct cxl_mem *cxlm)
goto out;
}
- md_status = readq(cxlm->memdev_regs + CXLMDEV_STATUS_OFFSET);
+ md_status = readq(cxlm->regs.memdev + CXLMDEV_STATUS_OFFSET);
if (!(md_status & CXLMDEV_MBOX_IF_READY && CXLMDEV_READY(md_status))) {
dev_err(dev, "mbox: reported doorbell ready, but not mbox ready\n");
rc = -EBUSY;
@@ -868,7 +868,7 @@ static int cxl_mem_setup_regs(struct cxl_mem *cxlm)
int cap, cap_count;
u64 cap_array;
- cap_array = readq(cxlm->regs + CXLDEV_CAP_ARRAY_OFFSET);
+ cap_array = readq(cxlm->base + CXLDEV_CAP_ARRAY_OFFSET);
if (FIELD_GET(CXLDEV_CAP_ARRAY_ID_MASK, cap_array) !=
CXLDEV_CAP_ARRAY_CAP_ID)
return -ENODEV;
@@ -881,25 +881,25 @@ static int cxl_mem_setup_regs(struct cxl_mem *cxlm)
u16 cap_id;
cap_id = FIELD_GET(CXLDEV_CAP_HDR_CAP_ID_MASK,
- readl(cxlm->regs + cap * 0x10));
- offset = readl(cxlm->regs + cap * 0x10 + 0x4);
- register_block = cxlm->regs + offset;
+ readl(cxlm->base + cap * 0x10));
+ offset = readl(cxlm->base + cap * 0x10 + 0x4);
+ register_block = cxlm->base + offset;
switch (cap_id) {
case CXLDEV_CAP_CAP_ID_DEVICE_STATUS:
dev_dbg(dev, "found Status capability (0x%x)\n", offset);
- cxlm->status_regs = register_block;
+ cxlm->regs.status = register_block;
break;
case CXLDEV_CAP_CAP_ID_PRIMARY_MAILBOX:
dev_dbg(dev, "found Mailbox capability (0x%x)\n", offset);
- cxlm->mbox_regs = register_block;
+ cxlm->regs.mbox = register_block;
break;
case CXLDEV_CAP_CAP_ID_SECONDARY_MAILBOX:
dev_dbg(dev, "found Secondary Mailbox capability (0x%x)\n", offset);
break;
case CXLDEV_CAP_CAP_ID_MEMDEV:
dev_dbg(dev, "found Memory Device capability (0x%x)\n", offset);
- cxlm->memdev_regs = register_block;
+ cxlm->regs.memdev = register_block;
break;
default:
dev_dbg(dev, "Unknown cap ID: %d (0x%x)\n", cap_id, offset);
@@ -907,11 +907,11 @@ static int cxl_mem_setup_regs(struct cxl_mem *cxlm)
}
}
- if (!cxlm->status_regs || !cxlm->mbox_regs || !cxlm->memdev_regs) {
+ if (!cxlm->regs.status || !cxlm->regs.mbox || !cxlm->regs.memdev) {
dev_err(dev, "registers not found: %s%s%s\n",
- !cxlm->status_regs ? "status " : "",
- !cxlm->mbox_regs ? "mbox " : "",
- !cxlm->memdev_regs ? "memdev" : "");
+ !cxlm->regs.status ? "status " : "",
+ !cxlm->regs.mbox ? "mbox " : "",
+ !cxlm->regs.memdev ? "memdev" : "");
return -ENXIO;
}
@@ -920,7 +920,7 @@ static int cxl_mem_setup_regs(struct cxl_mem *cxlm)
static int cxl_mem_setup_mailbox(struct cxl_mem *cxlm)
{
- const int cap = readl(cxlm->mbox_regs + CXLDEV_MBOX_CAPS_OFFSET);
+ const int cap = readl(cxlm->regs.mbox + CXLDEV_MBOX_CAPS_OFFSET);
cxlm->payload_size =
1 << FIELD_GET(CXLDEV_MBOX_CAP_PAYLOAD_SIZE_MASK, cap);
@@ -980,7 +980,7 @@ static struct cxl_mem *cxl_mem_create(struct pci_dev *pdev, u32 reg_lo,
mutex_init(&cxlm->mbox_mutex);
cxlm->pdev = pdev;
- cxlm->regs = regs + offset;
+ cxlm->base = regs + offset;
cxlm->enabled_cmds =
devm_kmalloc_array(dev, BITS_TO_LONGS(cxl_cmd_count),
sizeof(unsigned long),
@@ -1495,6 +1495,10 @@ static __init int cxl_mem_init(void)
dev_t devt;
int rc;
+ /* Double check the anonymous union trickery in struct cxl_regs */
+ BUILD_BUG_ON(offsetof(struct cxl_regs, memdev) !=
+ offsetof(struct cxl_regs, device_regs.memdev));
+
rc = alloc_chrdev_region(&devt, 0, CXL_MEM_MAX_DEVS, "cxl");
if (rc)
return rc;
diff --git a/drivers/cxl/mem.h b/drivers/cxl/mem.h
index daa9aba0e218..c247cf9c71af 100644
--- a/drivers/cxl/mem.h
+++ b/drivers/cxl/mem.h
@@ -53,10 +53,9 @@ struct cxl_memdev {
/**
* struct cxl_mem - A CXL memory device
* @pdev: The PCI device associated with this CXL device.
- * @regs: IO mappings to the device's MMIO
- * @status_regs: CXL 2.0 8.2.8.3 Device Status Registers
- * @mbox_regs: CXL 2.0 8.2.8.4 Mailbox Registers
- * @memdev_regs: CXL 2.0 8.2.8.5 Memory Device Registers
+ * @base: IO mappings to the device's MMIO
+ * @cxlmd: Logical memory device chardev / interface
+ * @regs: Parsed register blocks
* @payload_size: Size of space for payload
* (CXL 2.0 8.2.8.4.3 Mailbox Capabilities Register)
* @mbox_mutex: Mutex to synchronize mailbox access.
@@ -67,12 +66,10 @@ struct cxl_memdev {
*/
struct cxl_mem {
struct pci_dev *pdev;
- void __iomem *regs;
+ void __iomem *base;
struct cxl_memdev *cxlmd;
- void __iomem *status_regs;
- void __iomem *mbox_regs;
- void __iomem *memdev_regs;
+ struct cxl_regs regs;
size_t payload_size;
struct mutex mbox_mutex; /* Protects device mailbox and firmware */