[RFC PATCH v3 06/31] hw/cxl/device: Add memory device utilities

Ben Widawsky
2021-02-02T01:01:07Z

Memory devices implement extra capabilities on top of CXL devices. This
adds support for that.

A large part of memory devices is the mailbox/command interface. All of
the mailbox handling is done in the mailbox-utils library. Longer term,
new CXL devices that are being emulated may want to handle commands
differently, and therefore would need a mechanism to opt in/out of the
specific generic handlers. As such, this is considered sufficient for
now, but may need more depth in the future.

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
---
hw/cxl/cxl-device-utils.c | 38 ++++++++++++++++++++++++++++++++++++-
include/hw/cxl/cxl_device.h | 18 +++++++++++++++++-
2 files changed, 54 insertions(+), 2 deletions(-)

diff --git a/hw/cxl/cxl-device-utils.c b/hw/cxl/cxl-device-utils.c
index 6602606f3d..639ace523d 100644
--- a/hw/cxl/cxl-device-utils.c
+++ b/hw/cxl/cxl-device-utils.c
@@ -130,6 +130,31 @@ static void mailbox_reg_write(void *opaque, hwaddr offset, uint64_t value,
cxl_process_mailbox(cxl_dstate);
}

+static uint64_t mdev_reg_read(void *opaque, hwaddr offset, unsigned size)
+{
+ uint64_t retval = 0;
+
+ retval = FIELD_DP64(retval, CXL_MEM_DEV_STS, MEDIA_STATUS, 1);
+ retval = FIELD_DP64(retval, CXL_MEM_DEV_STS, MBOX_READY, 1);
+
+ return retval;
+}
+
+static const MemoryRegionOps mdev_ops = {
+ .read = mdev_reg_read,
+ .write = NULL, /* memory device register is read only */
+ .endianness = DEVICE_LITTLE_ENDIAN,
+ .valid = {
+ .min_access_size = 1,
+ .max_access_size = 8,
+ .unaligned = false,
+ },
+ .impl = {
+ .min_access_size = 8,
+ .max_access_size = 8,
+ },
+};
+
static const MemoryRegionOps mailbox_ops = {
.read = mailbox_reg_read,
.write = mailbox_reg_write,
@@ -187,6 +212,9 @@ void cxl_device_register_block_init(Object *obj, CXLDeviceState *cxl_dstate)
"device-status", CXL_DEVICE_REGISTERS_LENGTH);
memory_region_init_io(&cxl_dstate->mailbox, obj, &mailbox_ops, cxl_dstate,
"mailbox", CXL_MAILBOX_REGISTERS_LENGTH);
+ memory_region_init_io(&cxl_dstate->memory_device, obj, &mdev_ops,
+ cxl_dstate, "memory device caps",
+ CXL_MEMORY_DEVICE_REGISTERS_LENGTH);

memory_region_add_subregion(&cxl_dstate->device_registers, 0,
&cxl_dstate->caps);
@@ -196,6 +224,9 @@ void cxl_device_register_block_init(Object *obj, CXLDeviceState *cxl_dstate)
memory_region_add_subregion(&cxl_dstate->device_registers,
CXL_MAILBOX_REGISTERS_OFFSET,
&cxl_dstate->mailbox);
+ memory_region_add_subregion(&cxl_dstate->device_registers,
+ CXL_MEMORY_DEVICE_REGISTERS_OFFSET,
+ &cxl_dstate->memory_device);
}

static void device_reg_init_common(CXLDeviceState *cxl_dstate) { }
@@ -208,10 +239,12 @@ static void mailbox_reg_init_common(CXLDeviceState *cxl_dstate)
cxl_dstate->payload_size = CXL_MAILBOX_MAX_PAYLOAD_SIZE;
}

+static void memdev_reg_init_common(CXLDeviceState *cxl_dstate) { }
+
void cxl_device_register_init_common(CXLDeviceState *cxl_dstate)
{
uint32_t *cap_hdrs = cxl_dstate->caps_reg_state32;
- const int cap_count = 2;
+ const int cap_count = 3;

/* CXL Device Capabilities Array Register */
ARRAY_FIELD_DP32(cap_hdrs, CXL_DEV_CAP_ARRAY, CAP_ID, 0);
@@ -224,5 +257,8 @@ void cxl_device_register_init_common(CXLDeviceState *cxl_dstate)
cxl_device_cap_init(cxl_dstate, MAILBOX, 2);
mailbox_reg_init_common(cxl_dstate);

+ cxl_device_cap_init(cxl_dstate, MEMORY_DEVICE, 0x4000);
+ memdev_reg_init_common(cxl_dstate);
+
assert(cxl_initialize_mailbox(cxl_dstate) == 0);
}
diff --git a/include/hw/cxl/cxl_device.h b/include/hw/cxl/cxl_device.h
index af91bec10c..0cc5354ba4 100644
--- a/include/hw/cxl/cxl_device.h
+++ b/include/hw/cxl/cxl_device.h
@@ -72,15 +72,20 @@
#define CXL_MAILBOX_REGISTERS_LENGTH \
(CXL_MAILBOX_REGISTERS_SIZE + CXL_MAILBOX_MAX_PAYLOAD_SIZE)

+#define CXL_MEMORY_DEVICE_REGISTERS_OFFSET \
+ (CXL_MAILBOX_REGISTERS_OFFSET + CXL_MAILBOX_REGISTERS_LENGTH)
+#define CXL_MEMORY_DEVICE_REGISTERS_LENGTH 0x8
+
#define CXL_MMIO_SIZE \
CXL_DEVICE_CAP_REG_SIZE + CXL_DEVICE_REGISTERS_LENGTH + \
- CXL_MAILBOX_REGISTERS_LENGTH
+ CXL_MAILBOX_REGISTERS_LENGTH + CXL_MEMORY_DEVICE_REGISTERS_LENGTH

typedef struct cxl_device_state {
MemoryRegion device_registers;

/* mmio for device capabilities array - 8.2.8.2 */
MemoryRegion device;
+ MemoryRegion memory_device;
struct {
MemoryRegion caps;
uint32_t caps_reg_state32[CXL_CAPS_SIZE / 4];
@@ -145,6 +150,9 @@ REG32(CXL_DEV_CAP_ARRAY2, 4) /* We're going to pretend it's 64b */
CXL_DEVICE_CAPABILITY_HEADER_REGISTER(DEVICE, CXL_DEVICE_CAP_HDR1_OFFSET)
CXL_DEVICE_CAPABILITY_HEADER_REGISTER(MAILBOX, CXL_DEVICE_CAP_HDR1_OFFSET + \
CXL_DEVICE_CAP_REG_SIZE)
+CXL_DEVICE_CAPABILITY_HEADER_REGISTER(MEMORY_DEVICE,
+ CXL_DEVICE_CAP_HDR1_OFFSET +
+ CXL_DEVICE_CAP_REG_SIZE * 2)

int cxl_initialize_mailbox(CXLDeviceState *cxl_dstate);
void cxl_process_mailbox(CXLDeviceState *cxl_dstate);
@@ -197,4 +205,12 @@ REG32(CXL_DEV_BG_CMD_STS, 0x18)

REG32(CXL_DEV_CMD_PAYLOAD, 0x20)

+/* XXX: actually a 64b registers */
+REG32(CXL_MEM_DEV_STS, 0)
+ FIELD(CXL_MEM_DEV_STS, FATAL, 0, 1)
+ FIELD(CXL_MEM_DEV_STS, FW_HALT, 1, 1)
+ FIELD(CXL_MEM_DEV_STS, MEDIA_STATUS, 2, 2)
+ FIELD(CXL_MEM_DEV_STS, MBOX_READY, 4, 1)
+ FIELD(CXL_MEM_DEV_STS, RESET_NEEDED, 5, 3)
+
#endif
--
2.30.0