cdx: add MCDI protocol interface for firmware interaction

The MCDI (Management CPU Driver Interface) is used as a
protocol to communicate with the RPU firmware. It has
pre-defined set of messages for different message exchanges
between APU and RPU.
Signed-off-by: Puneet Gupta <puneet.gupta@amd.com>
Signed-off-by: Nipun Gupta <nipun.gupta@amd.com>
Signed-off-by: Tarak Reddy <tarak.reddy@amd.com>
Reviewed-by: Pieter Jansen van Vuuren <pieter.jansen-van-vuuren@amd.com>
Tested-by: Nikhil Agarwal <nikhil.agarwal@amd.com>
Link: https://lore.kernel.org/r/20230313132636.31850-5-nipun.gupta@amd.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/cdx/Kconfig

@@ -15,3 +15,5 @@ config CDX_BUS
 	  of CDX devices. CDX devices are memory mapped on system bus
 	  for embedded CPUs. CDX bus uses CDX controller and firmware
 	  to scan these CDX devices.
+
+source "drivers/cdx/controller/Kconfig"

drivers/cdx/Makefile

@@ -5,4 +5,4 @@
 # Copyright (C) 2022-2023, Advanced Micro Devices, Inc.
 #
 
-obj-$(CONFIG_CDX_BUS) += cdx.o
+obj-$(CONFIG_CDX_BUS) += cdx.o controller/

drivers/cdx/controller/Kconfig

+# SPDX-License-Identifier: GPL-2.0-only
+#
+# CDX controller configuration
+#
+# Copyright (C) 2022-2023, Advanced Micro Devices, Inc.
+#
+
+if CDX_BUS
+
+config MCDI_LOGGING
+	bool "MCDI Logging for the CDX controller"
+	depends on CDX_CONTROLLER
+	help
+	  Enable MCDI Logging for
+	  the CDX Controller for debug
+	  purpose.
+
+	  If unsure, say N.
+
+endif

drivers/cdx/controller/Makefile

+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for CDX controller drivers
+#
+# Copyright (C) 2022-2023, Advanced Micro Devices, Inc.
+#
+
+obj-$(CONFIG_CDX_CONTROLLER) += cdx-controller.o
+cdx-controller-objs := mcdi.o

drivers/cdx/controller/bitfield.h

+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright 2005-2006 Fen Systems Ltd.
+ * Copyright 2006-2013 Solarflare Communications Inc.
+ * Copyright (C) 2022-2023, Advanced Micro Devices, Inc.
+ */
+
+#ifndef CDX_BITFIELD_H
+#define CDX_BITFIELD_H
+
+#include <linux/bitfield.h>
+
+/* Lowest bit numbers and widths */
+#define CDX_DWORD_LBN 0
+#define CDX_DWORD_WIDTH 32
+
+/* Specified attribute (e.g. LBN) of the specified field */
+#define CDX_VAL(field, attribute) field ## _ ## attribute
+/* Low bit number of the specified field */
+#define CDX_LOW_BIT(field) CDX_VAL(field, LBN)
+/* Bit width of the specified field */
+#define CDX_WIDTH(field) CDX_VAL(field, WIDTH)
+/* High bit number of the specified field */
+#define CDX_HIGH_BIT(field) (CDX_LOW_BIT(field) + CDX_WIDTH(field) - 1)
+
+/* A doubleword (i.e. 4 byte) datatype - little-endian in HW */
+struct cdx_dword {
+	__le32 cdx_u32;
+};
+
+/* Value expanders for printk */
+#define CDX_DWORD_VAL(dword)				\
+	((unsigned int)le32_to_cpu((dword).cdx_u32))
+
+/*
+ * Extract bit field portion [low,high) from the 32-bit little-endian
+ * element which contains bits [min,max)
+ */
+#define CDX_DWORD_FIELD(dword, field)					\
+	(FIELD_GET(GENMASK(CDX_HIGH_BIT(field), CDX_LOW_BIT(field)),	\
+		   le32_to_cpu((dword).cdx_u32)))
+
+/*
+ * Creates the portion of the named bit field that lies within the
+ * range [min,max).
+ */
+#define CDX_INSERT_FIELD(field, value)				\
+	(FIELD_PREP(GENMASK(CDX_HIGH_BIT(field),		\
+			    CDX_LOW_BIT(field)), value))
+
+/*
+ * Creates the portion of the named bit fields that lie within the
+ * range [min,max).
+ */
+#define CDX_INSERT_FIELDS(field1, value1,		\
+			  field2, value2,		\
+			  field3, value3,		\
+			  field4, value4,		\
+			  field5, value5,		\
+			  field6, value6,		\
+			  field7, value7)		\
+	(CDX_INSERT_FIELD(field1, (value1)) |		\
+	 CDX_INSERT_FIELD(field2, (value2)) |		\
+	 CDX_INSERT_FIELD(field3, (value3)) |		\
+	 CDX_INSERT_FIELD(field4, (value4)) |		\
+	 CDX_INSERT_FIELD(field5, (value5)) |		\
+	 CDX_INSERT_FIELD(field6, (value6)) |		\
+	 CDX_INSERT_FIELD(field7, (value7)))
+
+#define CDX_POPULATE_DWORD(dword, ...)					\
+	(dword).cdx_u32 = cpu_to_le32(CDX_INSERT_FIELDS(__VA_ARGS__))
+
+/* Populate a dword field with various numbers of arguments */
+#define CDX_POPULATE_DWORD_7 CDX_POPULATE_DWORD
+#define CDX_POPULATE_DWORD_6(dword, ...) \
+	CDX_POPULATE_DWORD_7(dword, CDX_DWORD, 0, __VA_ARGS__)
+#define CDX_POPULATE_DWORD_5(dword, ...) \
+	CDX_POPULATE_DWORD_6(dword, CDX_DWORD, 0, __VA_ARGS__)
+#define CDX_POPULATE_DWORD_4(dword, ...) \
+	CDX_POPULATE_DWORD_5(dword, CDX_DWORD, 0, __VA_ARGS__)
+#define CDX_POPULATE_DWORD_3(dword, ...) \
+	CDX_POPULATE_DWORD_4(dword, CDX_DWORD, 0, __VA_ARGS__)
+#define CDX_POPULATE_DWORD_2(dword, ...) \
+	CDX_POPULATE_DWORD_3(dword, CDX_DWORD, 0, __VA_ARGS__)
+#define CDX_POPULATE_DWORD_1(dword, ...) \
+	CDX_POPULATE_DWORD_2(dword, CDX_DWORD, 0, __VA_ARGS__)
+#define CDX_SET_DWORD(dword) \
+	CDX_POPULATE_DWORD_1(dword, CDX_DWORD, 0xffffffff)
+
+#endif /* CDX_BITFIELD_H */

drivers/cdx/controller/mcdi.h

+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright 2008-2013 Solarflare Communications Inc.
+ * Copyright (C) 2022-2023, Advanced Micro Devices, Inc.
+ */
+
+#ifndef CDX_MCDI_H
+#define CDX_MCDI_H
+
+#include <linux/mutex.h>
+#include <linux/kref.h>
+
+#include "bitfield.h"
+#include "mc_cdx_pcol.h"
+
+#ifdef DEBUG
+#define CDX_WARN_ON_ONCE_PARANOID(x) WARN_ON_ONCE(x)
+#define CDX_WARN_ON_PARANOID(x) WARN_ON(x)
+#else
+#define CDX_WARN_ON_ONCE_PARANOID(x) do {} while (0)
+#define CDX_WARN_ON_PARANOID(x) do {} while (0)
+#endif
+
+/**
+ * enum cdx_mcdi_mode - MCDI transaction mode
+ * @MCDI_MODE_EVENTS: wait for an mcdi response callback.
+ * @MCDI_MODE_FAIL: we think MCDI is dead, so fail-fast all calls
+ */
+enum cdx_mcdi_mode {
+	MCDI_MODE_EVENTS,
+	MCDI_MODE_FAIL,
+};
+
+#define MCDI_RPC_TIMEOUT	(10 * HZ)
+#define MCDI_RPC_LONG_TIMEOU	(60 * HZ)
+#define MCDI_RPC_POST_RST_TIME	(10 * HZ)
+
+#define MCDI_BUF_LEN (8 + MCDI_CTL_SDU_LEN_MAX)
+
+/**
+ * enum cdx_mcdi_cmd_state - State for an individual MCDI command
+ * @MCDI_STATE_QUEUED: Command not started and is waiting to run.
+ * @MCDI_STATE_RETRY: Command was submitted and MC rejected with no resources,
+ *	as MC have too many outstanding commands. Command will be retried once
+ *	another command returns.
+ * @MCDI_STATE_RUNNING: Command was accepted and is running.
+ * @MCDI_STATE_RUNNING_CANCELLED: Command is running but the issuer cancelled
+ *	the command.
+ * @MCDI_STATE_FINISHED: Processing of this command has completed.
+ */
+
+enum cdx_mcdi_cmd_state {
+	MCDI_STATE_QUEUED,
+	MCDI_STATE_RETRY,
+	MCDI_STATE_RUNNING,
+	MCDI_STATE_RUNNING_CANCELLED,
+	MCDI_STATE_FINISHED,
+};
+
+/**
+ * struct cdx_mcdi - CDX MCDI Firmware interface, to interact
+ *	with CDX controller.
+ * @mcdi: MCDI interface
+ * @mcdi_ops: MCDI operations
+ */
+struct cdx_mcdi {
+	/* MCDI interface */
+	struct cdx_mcdi_data *mcdi;
+	const struct cdx_mcdi_ops *mcdi_ops;
+};
+
+struct cdx_mcdi_ops {
+	void (*mcdi_request)(struct cdx_mcdi *cdx,
+			     const struct cdx_dword *hdr, size_t hdr_len,
+			     const struct cdx_dword *sdu, size_t sdu_len);
+	unsigned int (*mcdi_rpc_timeout)(struct cdx_mcdi *cdx, unsigned int cmd);
+};
+
+typedef void cdx_mcdi_async_completer(struct cdx_mcdi *cdx,
+				      unsigned long cookie, int rc,
+				      struct cdx_dword *outbuf,
+				      size_t outlen_actual);
+
+/**
+ * struct cdx_mcdi_cmd - An outstanding MCDI command
+ * @ref: Reference count. There will be one reference if the command is
+ *	in the mcdi_iface cmd_list, another if it's on a cleanup list,
+ *	and a third if it's queued in the work queue.
+ * @list: The data for this entry in mcdi->cmd_list
+ * @cleanup_list: The data for this entry in a cleanup list
+ * @work: The work item for this command, queued in mcdi->workqueue
+ * @mcdi: The mcdi_iface for this command
+ * @state: The state of this command
+ * @inlen: inbuf length
+ * @inbuf: Input buffer
+ * @quiet: Whether to silence errors
+ * @reboot_seen: Whether a reboot has been seen during this command,
+ *	to prevent duplicates
+ * @seq: Sequence number
+ * @started: Jiffies this command was started at
+ * @cookie: Context for completion function
+ * @completer: Completion function
+ * @handle: Command handle
+ * @cmd: Command number
+ * @rc: Return code
+ * @outlen: Length of output buffer
+ * @outbuf: Output buffer
+ */
+struct cdx_mcdi_cmd {
+	struct kref ref;
+	struct list_head list;
+	struct list_head cleanup_list;
+	struct work_struct work;
+	struct cdx_mcdi_iface *mcdi;
+	enum cdx_mcdi_cmd_state state;
+	size_t inlen;
+	const struct cdx_dword *inbuf;
+	bool quiet;
+	bool reboot_seen;
+	u8 seq;
+	unsigned long started;
+	unsigned long cookie;
+	cdx_mcdi_async_completer *completer;
+	unsigned int handle;
+	unsigned int cmd;
+	int rc;
+	size_t outlen;
+	struct cdx_dword *outbuf;
+	/* followed by inbuf data if necessary */
+};
+
+/**
+ * struct cdx_mcdi_iface - MCDI protocol context
+ * @cdx: The associated NIC
+ * @iface_lock: Serialise access to this structure
+ * @outstanding_cleanups: Count of cleanups
+ * @cmd_list: List of outstanding and running commands
+ * @workqueue: Workqueue used for delayed processing
+ * @cmd_complete_wq: Waitqueue for command completion
+ * @db_held_by: Command the MC doorbell is in use by
+ * @seq_held_by: Command each sequence number is in use by
+ * @prev_handle: The last used command handle
+ * @mode: Poll for mcdi completion, or wait for an mcdi_event
+ * @prev_seq: The last used sequence number
+ * @new_epoch: Indicates start of day or start of MC reboot recovery
+ * @logging_buffer: Buffer that may be used to build MCDI tracing messages
+ * @logging_enabled: Whether to trace MCDI
+ */
+struct cdx_mcdi_iface {
+	struct cdx_mcdi *cdx;
+	/* Serialise access */
+	struct mutex iface_lock;
+	unsigned int outstanding_cleanups;
+	struct list_head cmd_list;
+	struct workqueue_struct *workqueue;
+	wait_queue_head_t cmd_complete_wq;
+	struct cdx_mcdi_cmd *db_held_by;
+	struct cdx_mcdi_cmd *seq_held_by[16];
+	unsigned int prev_handle;
+	enum cdx_mcdi_mode mode;
+	u8 prev_seq;
+	bool new_epoch;
+#ifdef CONFIG_MCDI_LOGGING
+	bool logging_enabled;
+	char *logging_buffer;
+#endif
+};
+
+/**
+ * struct cdx_mcdi_data - extra state for NICs that implement MCDI
+ * @iface: Interface/protocol state
+ * @fn_flags: Flags for this function, as returned by %MC_CMD_DRV_ATTACH.
+ */
+struct cdx_mcdi_data {
+	struct cdx_mcdi_iface iface;
+	u32 fn_flags;
+};
+
+static inline struct cdx_mcdi_iface *cdx_mcdi_if(struct cdx_mcdi *cdx)
+{
+	return cdx->mcdi ? &cdx->mcdi->iface : NULL;
+}
+
+int cdx_mcdi_init(struct cdx_mcdi *cdx);
+void cdx_mcdi_finish(struct cdx_mcdi *cdx);
+
+void cdx_mcdi_process_cmd(struct cdx_mcdi *cdx, struct cdx_dword *outbuf, int len);
+int cdx_mcdi_rpc(struct cdx_mcdi *cdx, unsigned int cmd,
+		 const struct cdx_dword *inbuf, size_t inlen,
+		 struct cdx_dword *outbuf, size_t outlen, size_t *outlen_actual);
+int cdx_mcdi_rpc_async(struct cdx_mcdi *cdx, unsigned int cmd,
+		       const struct cdx_dword *inbuf, size_t inlen,
+		       cdx_mcdi_async_completer *complete,
+		       unsigned long cookie);
+int cdx_mcdi_wait_for_quiescence(struct cdx_mcdi *cdx,
+				 unsigned int timeout_jiffies);
+
+/*
+ * We expect that 16- and 32-bit fields in MCDI requests and responses
+ * are appropriately aligned, but 64-bit fields are only
+ * 32-bit-aligned.
+ */
+#define MCDI_DECLARE_BUF(_name, _len) struct cdx_dword _name[DIV_ROUND_UP(_len, 4)] = {{0}}
+#define _MCDI_PTR(_buf, _offset)					\
+	((u8 *)(_buf) + (_offset))
+#define MCDI_PTR(_buf, _field)						\
+	_MCDI_PTR(_buf, MC_CMD_ ## _field ## _OFST)
+#define _MCDI_CHECK_ALIGN(_ofst, _align)				\
+	((void)BUILD_BUG_ON_ZERO((_ofst) & ((_align) - 1)),		\
+	 (_ofst))
+#define _MCDI_DWORD(_buf, _field)					\
+	((_buf) + (_MCDI_CHECK_ALIGN(MC_CMD_ ## _field ## _OFST, 4) >> 2))
+
+#define MCDI_BYTE(_buf, _field)						\
+	((void)BUILD_BUG_ON_ZERO(MC_CMD_ ## _field ## _LEN != 1),	\
+	 *MCDI_PTR(_buf, _field))
+#define MCDI_WORD(_buf, _field)						\
+	((void)BUILD_BUG_ON_ZERO(MC_CMD_ ## _field ## _LEN != 2),	\
+	 le16_to_cpu(*(__force const __le16 *)MCDI_PTR(_buf, _field)))
+#define MCDI_SET_DWORD(_buf, _field, _value)				\
+	CDX_POPULATE_DWORD_1(*_MCDI_DWORD(_buf, _field), CDX_DWORD, _value)
+#define MCDI_DWORD(_buf, _field)					\
+	CDX_DWORD_FIELD(*_MCDI_DWORD(_buf, _field), CDX_DWORD)
+#define MCDI_POPULATE_DWORD_1(_buf, _field, _name1, _value1)		\
+	CDX_POPULATE_DWORD_1(*_MCDI_DWORD(_buf, _field),		\
+			     MC_CMD_ ## _name1, _value1)
+#define MCDI_SET_QWORD(_buf, _field, _value)				\
+	do {								\
+		CDX_POPULATE_DWORD_1(_MCDI_DWORD(_buf, _field)[0],	\
+				     CDX_DWORD, (u32)(_value));	\
+		CDX_POPULATE_DWORD_1(_MCDI_DWORD(_buf, _field)[1],	\
+				     CDX_DWORD, (u64)(_value) >> 32);	\
+	} while (0)
+#define MCDI_QWORD(_buf, _field)					\
+	(CDX_DWORD_FIELD(_MCDI_DWORD(_buf, _field)[0], CDX_DWORD) |	\
+	(u64)CDX_DWORD_FIELD(_MCDI_DWORD(_buf, _field)[1], CDX_DWORD) << 32)
+
+#endif /* CDX_MCDI_H */