1/* SPDX-License-Identifier: GPL-2.0 */
  2/*
  3 * System Control and Management Interface (SCMI) Message Protocol
  4 * driver common header file containing some definitions, structures
  5 * and function prototypes used in all the different SCMI protocols.
  6 *
  7 * Copyright (C) 2018 ARM Ltd.
  8 */
  9#ifndef _SCMI_COMMON_H
 10#define _SCMI_COMMON_H
 11
 12#include <linux/bitfield.h>
 13#include <linux/completion.h>
 14#include <linux/device.h>
 15#include <linux/errno.h>
 16#include <linux/kernel.h>
 17#include <linux/scmi_protocol.h>
 18#include <linux/types.h>
 19
 20#include <asm/unaligned.h>
 21
 22#define PROTOCOL_REV_MINOR_MASK	GENMASK(15, 0)
 23#define PROTOCOL_REV_MAJOR_MASK	GENMASK(31, 16)
 24#define PROTOCOL_REV_MAJOR(x)	(u16)(FIELD_GET(PROTOCOL_REV_MAJOR_MASK, (x)))
 25#define PROTOCOL_REV_MINOR(x)	(u16)(FIELD_GET(PROTOCOL_REV_MINOR_MASK, (x)))
 26#define MAX_PROTOCOLS_IMP	16
 27#define MAX_OPPS		16
 28
 29enum scmi_common_cmd {
 30	PROTOCOL_VERSION = 0x0,
 31	PROTOCOL_ATTRIBUTES = 0x1,
 32	PROTOCOL_MESSAGE_ATTRIBUTES = 0x2,
 33};
 34
 35/**
 36 * struct scmi_msg_resp_prot_version - Response for a message
 37 *
 38 * @minor_version: Minor version of the ABI that firmware supports
 39 * @major_version: Major version of the ABI that firmware supports
 40 *
 41 * In general, ABI version changes follow the rule that minor version increments
 42 * are backward compatible. Major revision changes in ABI may not be
 43 * backward compatible.
 44 *
 45 * Response to a generic message with message type SCMI_MSG_VERSION
 46 */
 47struct scmi_msg_resp_prot_version {
 48	__le16 minor_version;
 49	__le16 major_version;
 50};
 51
 52#define MSG_ID_MASK		GENMASK(7, 0)
 53#define MSG_XTRACT_ID(hdr)	FIELD_GET(MSG_ID_MASK, (hdr))
 54#define MSG_TYPE_MASK		GENMASK(9, 8)
 55#define MSG_XTRACT_TYPE(hdr)	FIELD_GET(MSG_TYPE_MASK, (hdr))
 56#define MSG_TYPE_COMMAND	0
 57#define MSG_TYPE_DELAYED_RESP	2
 58#define MSG_TYPE_NOTIFICATION	3
 59#define MSG_PROTOCOL_ID_MASK	GENMASK(17, 10)
 60#define MSG_XTRACT_PROT_ID(hdr)	FIELD_GET(MSG_PROTOCOL_ID_MASK, (hdr))
 61#define MSG_TOKEN_ID_MASK	GENMASK(27, 18)
 62#define MSG_XTRACT_TOKEN(hdr)	FIELD_GET(MSG_TOKEN_ID_MASK, (hdr))
 63#define MSG_TOKEN_MAX		(MSG_XTRACT_TOKEN(MSG_TOKEN_ID_MASK) + 1)
 64
 65/**
 66 * struct scmi_msg_hdr - Message(Tx/Rx) header
 67 *
 68 * @id: The identifier of the message being sent
 69 * @protocol_id: The identifier of the protocol used to send @id message
 70 * @seq: The token to identify the message. When a message returns, the
 71 *	platform returns the whole message header unmodified including the
 72 *	token
 73 * @status: Status of the transfer once it's complete
 74 * @poll_completion: Indicate if the transfer needs to be polled for
 75 *	completion or interrupt mode is used
 76 */
 77struct scmi_msg_hdr {
 78	u8 id;
 79	u8 protocol_id;
 80	u16 seq;
 81	u32 status;
 82	bool poll_completion;
 83};
 84
 85/**
 86 * pack_scmi_header() - packs and returns 32-bit header
 87 *
 88 * @hdr: pointer to header containing all the information on message id,
 89 *	protocol id and sequence id.
 90 *
 91 * Return: 32-bit packed message header to be sent to the platform.
 92 */
 93static inline u32 pack_scmi_header(struct scmi_msg_hdr *hdr)
 94{
 95	return FIELD_PREP(MSG_ID_MASK, hdr->id) |
 96		FIELD_PREP(MSG_TOKEN_ID_MASK, hdr->seq) |
 97		FIELD_PREP(MSG_PROTOCOL_ID_MASK, hdr->protocol_id);
 98}
 99
100/**
101 * unpack_scmi_header() - unpacks and records message and protocol id
102 *
103 * @msg_hdr: 32-bit packed message header sent from the platform
104 * @hdr: pointer to header to fetch message and protocol id.
105 */
106static inline void unpack_scmi_header(u32 msg_hdr, struct scmi_msg_hdr *hdr)
107{
108	hdr->id = MSG_XTRACT_ID(msg_hdr);
109	hdr->protocol_id = MSG_XTRACT_PROT_ID(msg_hdr);
110}
111
112/**
113 * struct scmi_msg - Message(Tx/Rx) structure
114 *
115 * @buf: Buffer pointer
116 * @len: Length of data in the Buffer
117 */
118struct scmi_msg {
119	void *buf;
120	size_t len;
121};
122
123/**
124 * struct scmi_xfer - Structure representing a message flow
125 *
126 * @transfer_id: Unique ID for debug & profiling purpose
127 * @hdr: Transmit message header
128 * @tx: Transmit message
129 * @rx: Receive message, the buffer should be pre-allocated to store
130 *	message. If request-ACK protocol is used, we can reuse the same
131 *	buffer for the rx path as we use for the tx path.
132 * @done: command message transmit completion event
133 * @async_done: pointer to delayed response message received event completion
134 */
135struct scmi_xfer {
136	int transfer_id;
137	struct scmi_msg_hdr hdr;
138	struct scmi_msg tx;
139	struct scmi_msg rx;
140	struct completion done;
141	struct completion *async_done;
142};
143
144void scmi_xfer_put(const struct scmi_handle *h, struct scmi_xfer *xfer);
145int scmi_do_xfer(const struct scmi_handle *h, struct scmi_xfer *xfer);
146int scmi_do_xfer_with_response(const struct scmi_handle *h,
147			       struct scmi_xfer *xfer);
148int scmi_xfer_get_init(const struct scmi_handle *h, u8 msg_id, u8 prot_id,
149		       size_t tx_size, size_t rx_size, struct scmi_xfer **p);
150int scmi_handle_put(const struct scmi_handle *handle);
151struct scmi_handle *scmi_handle_get(struct device *dev);
152void scmi_set_handle(struct scmi_device *scmi_dev);
153int scmi_version_get(const struct scmi_handle *h, u8 protocol, u32 *version);
154void scmi_setup_protocol_implemented(const struct scmi_handle *handle,
155				     u8 *prot_imp);
156
157int scmi_base_protocol_init(struct scmi_handle *h);
158
159/* SCMI Transport */
160/**
161 * struct scmi_chan_info - Structure representing a SCMI channel information
162 *
163 * @dev: Reference to device in the SCMI hierarchy corresponding to this
164 *	 channel
165 * @handle: Pointer to SCMI entity handle
166 * @transport_info: Transport layer related information
167 */
168struct scmi_chan_info {
169	struct device *dev;
170	struct scmi_handle *handle;
171	void *transport_info;
172};
173
174/**
175 * struct scmi_transport_ops - Structure representing a SCMI transport ops
176 *
177 * @chan_available: Callback to check if channel is available or not
178 * @chan_setup: Callback to allocate and setup a channel
179 * @chan_free: Callback to free a channel
180 * @send_message: Callback to send a message
181 * @mark_txdone: Callback to mark tx as done
182 * @fetch_response: Callback to fetch response
183 * @fetch_notification: Callback to fetch notification
184 * @clear_channel: Callback to clear a channel
185 * @poll_done: Callback to poll transfer status
186 */
187struct scmi_transport_ops {
188	bool (*chan_available)(struct device *dev, int idx);
189	int (*chan_setup)(struct scmi_chan_info *cinfo, struct device *dev,
190			  bool tx);
191	int (*chan_free)(int id, void *p, void *data);
192	int (*send_message)(struct scmi_chan_info *cinfo,
193			    struct scmi_xfer *xfer);
194	void (*mark_txdone)(struct scmi_chan_info *cinfo, int ret);
195	void (*fetch_response)(struct scmi_chan_info *cinfo,
196			       struct scmi_xfer *xfer);
197	void (*fetch_notification)(struct scmi_chan_info *cinfo,
198				   size_t max_len, struct scmi_xfer *xfer);
199	void (*clear_channel)(struct scmi_chan_info *cinfo);
200	bool (*poll_done)(struct scmi_chan_info *cinfo, struct scmi_xfer *xfer);
201};
202
203/**
204 * struct scmi_desc - Description of SoC integration
205 *
206 * @ops: Pointer to the transport specific ops structure
207 * @max_rx_timeout_ms: Timeout for communication with SoC (in Milliseconds)
208 * @max_msg: Maximum number of messages that can be pending
209 *	simultaneously in the system
210 * @max_msg_size: Maximum size of data per message that can be handled.
211 */
212struct scmi_desc {
213	struct scmi_transport_ops *ops;
214	int max_rx_timeout_ms;
215	int max_msg;
216	int max_msg_size;
217};
218
219extern const struct scmi_desc scmi_mailbox_desc;
220#ifdef CONFIG_HAVE_ARM_SMCCC
221extern const struct scmi_desc scmi_smc_desc;
222#endif
223
224void scmi_rx_callback(struct scmi_chan_info *cinfo, u32 msg_hdr);
225void scmi_free_channel(struct scmi_chan_info *cinfo, struct idr *idr, int id);
226
227/* shmem related declarations */
228struct scmi_shared_mem;
229
230void shmem_tx_prepare(struct scmi_shared_mem __iomem *shmem,
231		      struct scmi_xfer *xfer);
232u32 shmem_read_header(struct scmi_shared_mem __iomem *shmem);
233void shmem_fetch_response(struct scmi_shared_mem __iomem *shmem,
234			  struct scmi_xfer *xfer);
235void shmem_fetch_notification(struct scmi_shared_mem __iomem *shmem,
236			      size_t max_len, struct scmi_xfer *xfer);
237void shmem_clear_channel(struct scmi_shared_mem __iomem *shmem);
238bool shmem_poll_done(struct scmi_shared_mem __iomem *shmem,
239		     struct scmi_xfer *xfer);
240
241#endif /* _SCMI_COMMON_H */