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-rw-r--r--include/uapi/linux/cxl_mem.h156
1 files changed, 156 insertions, 0 deletions
diff --git a/include/uapi/linux/cxl_mem.h b/include/uapi/linux/cxl_mem.h
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index 000000000000..887781dc3b6c
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+++ b/include/uapi/linux/cxl_mem.h
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+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * CXL IOCTLs for Memory Devices
+ */
+
+#ifndef _UAPI_CXL_MEM_H_
+#define _UAPI_CXL_MEM_H_
+
+#include <linux/types.h>
+
+/**
+ * DOC: UAPI
+ *
+ * Not all of all commands that the driver supports are always available for use
+ * by userspace. Userspace must check the results from the QUERY command in
+ * order to determine the live set of commands.
+ */
+
+#define CXL_MEM_QUERY_COMMANDS _IOR(0xCE, 1, struct cxl_mem_query_commands)
+#define CXL_MEM_SEND_COMMAND _IOWR(0xCE, 2, struct cxl_send_command)
+
+#define CXL_CMDS \
+ ___C(INVALID, "Invalid Command"), \
+ ___C(IDENTIFY, "Identify Command"), \
+ ___C(MAX, "invalid / last command")
+
+#define ___C(a, b) CXL_MEM_COMMAND_ID_##a
+enum { CXL_CMDS };
+
+#undef ___C
+#define ___C(a, b) { b }
+static const struct {
+ const char *name;
+} cxl_command_names[] = { CXL_CMDS };
+
+/*
+ * Here's how this actually breaks out:
+ * cxl_command_names[] = {
+ * [CXL_MEM_COMMAND_ID_INVALID] = { "Invalid Command" },
+ * [CXL_MEM_COMMAND_ID_IDENTIFY] = { "Identify Command" },
+ * ...
+ * [CXL_MEM_COMMAND_ID_MAX] = { "invalid / last command" },
+ * };
+ */
+
+#undef ___C
+
+/**
+ * struct cxl_command_info - Command information returned from a query.
+ * @id: ID number for the command.
+ * @flags: Flags that specify command behavior.
+ * @size_in: Expected input size, or -1 if variable length.
+ * @size_out: Expected output size, or -1 if variable length.
+ *
+ * Represents a single command that is supported by both the driver and the
+ * hardware. This is returned as part of an array from the query ioctl. The
+ * following would be a command that takes a variable length input and returns 0
+ * bytes of output.
+ *
+ * - @id = 10
+ * - @flags = 0
+ * - @size_in = -1
+ * - @size_out = 0
+ *
+ * See struct cxl_mem_query_commands.
+ */
+struct cxl_command_info {
+ __u32 id;
+
+ __u32 flags;
+#define CXL_MEM_COMMAND_FLAG_MASK GENMASK(0, 0)
+
+ __s32 size_in;
+ __s32 size_out;
+};
+
+/**
+ * struct cxl_mem_query_commands - Query supported commands.
+ * @n_commands: In/out parameter. When @n_commands is > 0, the driver will
+ * return min(num_support_commands, n_commands). When @n_commands
+ * is 0, driver will return the number of total supported commands.
+ * @rsvd: Reserved for future use.
+ * @commands: Output array of supported commands. This array must be allocated
+ * by userspace to be at least min(num_support_commands, @n_commands)
+ *
+ * Allow userspace to query the available commands supported by both the driver,
+ * and the hardware. Commands that aren't supported by either the driver, or the
+ * hardware are not returned in the query.
+ *
+ * Examples:
+ *
+ * - { .n_commands = 0 } // Get number of supported commands
+ * - { .n_commands = 15, .commands = buf } // Return first 15 (or less)
+ * supported commands
+ *
+ * See struct cxl_command_info.
+ */
+struct cxl_mem_query_commands {
+ /*
+ * Input: Number of commands to return (space allocated by user)
+ * Output: Number of commands supported by the driver/hardware
+ *
+ * If n_commands is 0, kernel will only return number of commands and
+ * not try to populate commands[], thus allowing userspace to know how
+ * much space to allocate
+ */
+ __u32 n_commands;
+ __u32 rsvd;
+
+ struct cxl_command_info __user commands[]; /* out: supported commands */
+};
+
+/**
+ * struct cxl_send_command - Send a command to a memory device.
+ * @id: The command to send to the memory device. This must be one of the
+ * commands returned by the query command.
+ * @flags: Flags for the command (input).
+ * @rsvd: Must be zero.
+ * @retval: Return value from the memory device (output).
+ * @in: Parameters associated with input payload.
+ * @in.size: Size of the payload to provide to the device (input).
+ * @in.rsvd: Must be zero.
+ * @in.payload: Pointer to memory for payload input, payload is little endian.
+ * @out: Parameters associated with output payload.
+ * @out.size: Size of the payload received from the device (input/output). This
+ * field is filled in by userspace to let the driver know how much
+ * space was allocated for output. It is populated by the driver to
+ * let userspace know how large the output payload actually was.
+ * @out.rsvd: Must be zero.
+ * @out.payload: Pointer to memory for payload output, payload is little endian.
+ *
+ * Mechanism for userspace to send a command to the hardware for processing. The
+ * driver will do basic validation on the command sizes. In some cases even the
+ * payload may be introspected. Userspace is required to allocate large enough
+ * buffers for size_out which can be variable length in certain situations.
+ */
+struct cxl_send_command {
+ __u32 id;
+ __u32 flags;
+ __u32 rsvd;
+ __u32 retval;
+
+ struct {
+ __s32 size;
+ __u32 rsvd;
+ __u64 payload;
+ } in;
+
+ struct {
+ __s32 size;
+ __u32 rsvd;
+ __u64 payload;
+ } out;
+};
+
+#endif