[PATCH v5 04/43] hw/cxl/device: Introduce a CXL device (8.2.8)

[Jonathan Cameron via <qemu-devel@nongnu.org>]

From: Ben Widawsky <ben.widawsky@intel.com>

A CXL device is a type of CXL component. Conceptually, a CXL device
would be a leaf node in a CXL topology. From an emulation perspective,
CXL devices are the most complex and so the actual implementation is
reserved for discrete commits.

This new device type is specifically catered towards the eventual
implementation of a Type3 CXL.mem device, 8.2.8.5 in the CXL 2.0
specification.

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
---
v5:
 Include the impacts of the published CXL 2.0 Errata F4 which clarified
 access permissions.
 - Documentation updates.
 - The 48 bit registers is gone.
 
 include/hw/cxl/cxl.h        |   1 +
 include/hw/cxl/cxl_device.h | 165 ++++++++++++++++++++++++++++++++++++
 2 files changed, 166 insertions(+)
 create mode 100644 include/hw/cxl/cxl_device.h

diff --git a/include/hw/cxl/cxl.h b/include/hw/cxl/cxl.h
index 8c738c7a2b..b9d1ac3fad 100644
--- a/include/hw/cxl/cxl.h
+++ b/include/hw/cxl/cxl.h
@@ -12,5 +12,6 @@
 
 #include "cxl_pci.h"
 #include "cxl_component.h"
+#include "cxl_device.h"
 
 #endif
diff --git a/include/hw/cxl/cxl_device.h b/include/hw/cxl/cxl_device.h
new file mode 100644
index 0000000000..b2416e45bf
--- /dev/null
+++ b/include/hw/cxl/cxl_device.h
@@ -0,0 +1,165 @@
+/*
+ * QEMU CXL Devices
+ *
+ * Copyright (c) 2020 Intel
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2. See the
+ * COPYING file in the top-level directory.
+ */
+
+#ifndef CXL_DEVICE_H
+#define CXL_DEVICE_H
+
+#include "hw/register.h"
+
+/*
+ * The following is how a CXL device's MMIO space is laid out. The only
+ * requirement from the spec is that the capabilities array and the capability
+ * headers start at offset 0 and are contiguously packed. The headers themselves
+ * provide offsets to the register fields. For this emulation, registers will
+ * start at offset 0x80 (m == 0x80). No secondary mailbox is implemented which
+ * means that n = m + sizeof(mailbox registers) + sizeof(device registers).
+ *
+ * This is roughly described in 8.2.8 Figure 138 of the CXL 2.0 spec.
+ *
+ *                       +---------------------------------+
+ *                       |                                 |
+ *                       |    Memory Device Registers      |
+ *                       |                                 |
+ * n + PAYLOAD_SIZE_MAX  -----------------------------------
+ *                  ^    |                                 |
+ *                  |    |                                 |
+ *                  |    |                                 |
+ *                  |    |                                 |
+ *                  |    |                                 |
+ *                  |    |         Mailbox Payload         |
+ *                  |    |                                 |
+ *                  |    |                                 |
+ *                  |    |                                 |
+ *                  |    -----------------------------------
+ *                  |    |       Mailbox Registers         |
+ *                  |    |                                 |
+ *                  n    -----------------------------------
+ *                  ^    |                                 |
+ *                  |    |        Device Registers         |
+ *                  |    |                                 |
+ *                  m    ---------------------------------->
+ *                  ^    |  Memory Device Capability Header|
+ *                  |    -----------------------------------
+ *                  |    |     Mailbox Capability Header   |
+ *                  |    -------------- --------------------
+ *                  |    |     Device Capability Header    |
+ *                  |    -----------------------------------
+ *                  |    |                                 |
+ *                  |    |                                 |
+ *                  |    |      Device Cap Array[0..n]     |
+ *                  |    |                                 |
+ *                  |    |                                 |
+ *                       |                                 |
+ *                  0    +---------------------------------+
+ *
+ */
+
+#define CXL_DEVICE_CAP_HDR1_OFFSET 0x10 /* Figure 138 */
+#define CXL_DEVICE_CAP_REG_SIZE 0x10 /* 8.2.8.2 */
+#define CXL_DEVICE_CAPS_MAX 4 /* 8.2.8.2.1 + 8.2.8.5 */
+
+#define CXL_DEVICE_REGISTERS_OFFSET 0x80 /* Read comment above */
+#define CXL_DEVICE_REGISTERS_LENGTH 0x8 /* 8.2.8.3.1 */
+
+#define CXL_MAILBOX_REGISTERS_OFFSET \
+    (CXL_DEVICE_REGISTERS_OFFSET + CXL_DEVICE_REGISTERS_LENGTH)
+#define CXL_MAILBOX_REGISTERS_SIZE 0x20 /* 8.2.8.4, Figure 139 */
+#define CXL_MAILBOX_PAYLOAD_SHIFT 11
+#define CXL_MAILBOX_MAX_PAYLOAD_SIZE (1 << CXL_MAILBOX_PAYLOAD_SHIFT)
+#define CXL_MAILBOX_REGISTERS_LENGTH \
+    (CXL_MAILBOX_REGISTERS_SIZE + CXL_MAILBOX_MAX_PAYLOAD_SIZE)
+
+typedef struct cxl_device_state {
+    MemoryRegion device_registers;
+
+    /* mmio for device capabilities array - 8.2.8.2 */
+    MemoryRegion device;
+    MemoryRegion caps;
+
+    /* mmio for the mailbox registers 8.2.8.4 */
+    MemoryRegion mailbox;
+
+    /* memory region for persistent memory, HDM */
+    uint64_t pmem_size;
+} CXLDeviceState;
+
+/* Initialize the register block for a device */
+void cxl_device_register_block_init(Object *obj, CXLDeviceState *dev);
+
+/* Set up default values for the register block */
+void cxl_device_register_init_common(CXLDeviceState *dev);
+
+/*
+ * CXL 2.0 - 8.2.8.1 including errata F4
+ * Documented as a 128 bit register, but 64 bit accesses and the second
+ * 64 bits are currently reserved.
+ */
+REG64(CXL_DEV_CAP_ARRAY, 0) /* Documented as 128 bit register but 64 byte accesses */
+    FIELD(CXL_DEV_CAP_ARRAY, CAP_ID, 0, 16)
+    FIELD(CXL_DEV_CAP_ARRAY, CAP_VERSION, 16, 8)
+    FIELD(CXL_DEV_CAP_ARRAY, CAP_COUNT, 32, 16)
+
+/*
+ * Helper macro to initialize capability headers for CXL devices.
+ *
+ * In the 8.2.8.2, this is listed as a 128b register, but in 8.2.8, it says:
+ * > No registers defined in Section 8.2.8 are larger than 64-bits wide so that
+ * > is the maximum access size allowed for these registers. If this rule is not
+ * > followed, the behavior is undefined
+ *
+ * CXL 2.0 Errata F4 states futher that the layouts in the specification are
+ * shown as greater than 128 bits, but implementations are expected to
+ * use any size of access up to 64 bits.
+ *
+ * Here we've chosen to make it 4 dwords. The spec allows any pow2 multiple
+ * access to be used for a register up to 64 bits.
+ */
+#define CXL_DEVICE_CAPABILITY_HEADER_REGISTER(n, offset)  \
+    REG32(CXL_DEV_##n##_CAP_HDR0, offset)                 \
+        FIELD(CXL_DEV_##n##_CAP_HDR0, CAP_ID, 0, 16)      \
+        FIELD(CXL_DEV_##n##_CAP_HDR0, CAP_VERSION, 16, 8) \
+    REG32(CXL_DEV_##n##_CAP_HDR1, offset + 4)             \
+        FIELD(CXL_DEV_##n##_CAP_HDR1, CAP_OFFSET, 0, 32)  \
+    REG32(CXL_DEV_##n##_CAP_HDR2, offset + 8)             \
+        FIELD(CXL_DEV_##n##_CAP_HDR2, CAP_LENGTH, 0, 32)
+
+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)
+
+REG32(CXL_DEV_MAILBOX_CAP, 0)
+    FIELD(CXL_DEV_MAILBOX_CAP, PAYLOAD_SIZE, 0, 5)
+    FIELD(CXL_DEV_MAILBOX_CAP, INT_CAP, 5, 1)
+    FIELD(CXL_DEV_MAILBOX_CAP, BG_INT_CAP, 6, 1)
+    FIELD(CXL_DEV_MAILBOX_CAP, MSI_N, 7, 4)
+
+REG32(CXL_DEV_MAILBOX_CTRL, 4)
+    FIELD(CXL_DEV_MAILBOX_CTRL, DOORBELL, 0, 1)
+    FIELD(CXL_DEV_MAILBOX_CTRL, INT_EN, 1, 1)
+    FIELD(CXL_DEV_MAILBOX_CTRL, BG_INT_EN, 2, 1)
+
+REG64(CXL_DEV_MAILBOX_CMD, 8)
+    FIELD(CXL_DEV_MAILBOX_CMD, COMMAND, 0, 8)
+    FIELD(CXL_DEV_MAILBOX_CMD, COMMAND_SET, 8, 8)
+    FIELD(CXL_DEV_MAILBOX_CMD, LENGTH, 16, 20)
+
+REG64(CXL_DEV_MAILBOX_STS, 0x10)
+    FIELD(CXL_DEV_MAILBOX_STS, BG_OP, 0, 1)
+    FIELD(CXL_DEV_MAILBOX_STS, ERRNO, 32, 16)
+    FIELD(CXL_DEV_MAILBOX_STS, VENDOR_ERRNO, 48, 16)
+
+REG64(CXL_DEV_BG_CMD_STS, 0x18)
+    FIELD(CXL_DEV_BG_CMD_STS, BG, 0, 16)
+    FIELD(CXL_DEV_BG_CMD_STS, DONE, 16, 7)
+    FIELD(CXL_DEV_BG_CMD_STS, ERRNO, 32, 16)
+    FIELD(CXL_DEV_BG_CMD_STS, VENDOR_ERRNO, 48, 16)
+
+REG32(CXL_DEV_CMD_PAYLOAD, 0x20)
+
+#endif
-- 
2.32.0