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// SPDX-License-Identifier: GPL-2.0
/*
* System Control and Management Interface (SCMI) Message Protocol driver
*
* SCMI Message Protocol is used between the System Control Processor(SCP)
* and the Application Processors(AP). The Message Handling Unit(MHU)
* provides a mechanism for inter-processor communication between SCP's
* Cortex M3 and AP.
*
* SCP offers control and management of the core/cluster power states,
* various power domain DVFS including the core/cluster, certain system
* clocks configuration, thermal sensors and many others.
*
* Copyright (C) 2018 ARM Ltd.
*/
#include <linux/bitmap.h>
#include <linux/export.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/ktime.h>
#include <linux/mailbox_client.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/processor.h>
#include <linux/semaphore.h>
#include <linux/slab.h>
#include "common.h"
#define MSG_ID_MASK GENMASK(7, 0)
#define MSG_TYPE_MASK GENMASK(9, 8)
#define MSG_PROTOCOL_ID_MASK GENMASK(17, 10)
#define MSG_TOKEN_ID_MASK GENMASK(27, 18)
#define MSG_XTRACT_TOKEN(hdr) FIELD_GET(MSG_TOKEN_ID_MASK, (hdr))
#define MSG_TOKEN_MAX (MSG_XTRACT_TOKEN(MSG_TOKEN_ID_MASK) + 1)
enum scmi_error_codes {
SCMI_SUCCESS = 0, /* Success */
SCMI_ERR_SUPPORT = -1, /* Not supported */
SCMI_ERR_PARAMS = -2, /* Invalid Parameters */
SCMI_ERR_ACCESS = -3, /* Invalid access/permission denied */
SCMI_ERR_ENTRY = -4, /* Not found */
SCMI_ERR_RANGE = -5, /* Value out of range */
SCMI_ERR_BUSY = -6, /* Device busy */
SCMI_ERR_COMMS = -7, /* Communication Error */
SCMI_ERR_GENERIC = -8, /* Generic Error */
SCMI_ERR_HARDWARE = -9, /* Hardware Error */
SCMI_ERR_PROTOCOL = -10,/* Protocol Error */
SCMI_ERR_MAX
};
/* List of all SCMI devices active in system */
static LIST_HEAD(scmi_list);
/* Protection for the entire list */
static DEFINE_MUTEX(scmi_list_mutex);
/**
* struct scmi_xfers_info - Structure to manage transfer information
*
* @xfer_block: Preallocated Message array
* @xfer_alloc_table: Bitmap table for allocated messages.
* Index of this bitmap table is also used for message
* sequence identifier.
* @xfer_lock: Protection for message allocation
*/
struct scmi_xfers_info {
struct scmi_xfer *xfer_block;
unsigned long *xfer_alloc_table;
spinlock_t xfer_lock;
};
/**
* struct scmi_desc - Description of SoC integration
*
* @max_rx_timeout_ms: Timeout for communication with SoC (in Milliseconds)
* @max_msg: Maximum number of messages that can be pending
* simultaneously in the system
* @max_msg_size: Maximum size of data per message that can be handled.
*/
struct scmi_desc {
int max_rx_timeout_ms;
int max_msg;
int max_msg_size;
};
/**
* struct scmi_chan_info - Structure representing a SCMI channel informfation
*
* @cl: Mailbox Client
* @chan: Transmit/Receive mailbox channel
* @payload: Transmit/Receive mailbox channel payload area
* @dev: Reference to device in the SCMI hierarchy corresponding to this
* channel
* @handle: Pointer to SCMI entity handle
*/
struct scmi_chan_info {
struct mbox_client cl;
struct mbox_chan *chan;
void __iomem *payload;
struct device *dev;
struct scmi_handle *handle;
};
/**
* struct scmi_info - Structure representing a SCMI instance
*
* @dev: Device pointer
* @desc: SoC description for this instance
* @handle: Instance of SCMI handle to send to clients
* @version: SCMI revision information containing protocol version,
* implementation version and (sub-)vendor identification.
* @minfo: Message info
* @tx_idr: IDR object to map protocol id to channel info pointer
* @protocols_imp: List of protocols implemented, currently maximum of
* MAX_PROTOCOLS_IMP elements allocated by the base protocol
* @node: List head
* @users: Number of users of this instance
*/
struct scmi_info {
struct device *dev;
const struct scmi_desc *desc;
struct scmi_revision_info version;
struct scmi_handle handle;
struct scmi_xfers_info minfo;
struct idr tx_idr;
u8 *protocols_imp;
struct list_head node;
int users;
};
#define client_to_scmi_chan_info(c) container_of(c, struct scmi_chan_info, cl)
#define handle_to_scmi_info(h) container_of(h, struct scmi_info, handle)
/*
* SCMI specification requires all parameters, message headers, return
* arguments or any protocol data to be expressed in little endian
* format only.
*/
struct scmi_shared_mem {
__le32 reserved;
__le32 channel_status;
#define SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR BIT(1)
#define SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE BIT(0)
__le32 reserved1[2];
__le32 flags;
#define SCMI_SHMEM_FLAG_INTR_ENABLED BIT(0)
__le32 length;
__le32 msg_header;
u8 msg_payload[0];
};
static const int scmi_linux_errmap[] = {
/* better than switch case as long as return value is continuous */
0, /* SCMI_SUCCESS */
-EOPNOTSUPP, /* SCMI_ERR_SUPPORT */
-EINVAL, /* SCMI_ERR_PARAM */
-EACCES, /* SCMI_ERR_ACCESS */
-ENOENT, /* SCMI_ERR_ENTRY */
-ERANGE, /* SCMI_ERR_RANGE */
-EBUSY, /* SCMI_ERR_BUSY */
-ECOMM, /* SCMI_ERR_COMMS */
-EIO, /* SCMI_ERR_GENERIC */
-EREMOTEIO, /* SCMI_ERR_HARDWARE */
-EPROTO, /* SCMI_ERR_PROTOCOL */
};
static inline int scmi_to_linux_errno(int errno)
{
if (errno < SCMI_SUCCESS && errno > SCMI_ERR_MAX)
return scmi_linux_errmap[-errno];
return -EIO;
}
/**
* scmi_dump_header_dbg() - Helper to dump a message header.
*
* @dev: Device pointer corresponding to the SCMI entity
* @hdr: pointer to header.
*/
static inline void scmi_dump_header_dbg(struct device *dev,
struct scmi_msg_hdr *hdr)
{
dev_dbg(dev, "Command ID: %x Sequence ID: %x Protocol: %x\n",
hdr->id, hdr->seq, hdr->protocol_id);
}
static void scmi_fetch_response(struct scmi_xfer *xfer,
struct scmi_shared_mem __iomem *mem)
{
xfer->hdr.status = ioread32(mem->msg_payload);
/* Skip the length of header and statues in payload area i.e 8 bytes*/
xfer->rx.len = min_t(size_t, xfer->rx.len, ioread32(&mem->length) - 8);
/* Take a copy to the rx buffer.. */
memcpy_fromio(xfer->rx.buf, mem->msg_payload + 4, xfer->rx.len);
}
/**
* scmi_rx_callback() - mailbox client callback for receive messages
*
* @cl: client pointer
* @m: mailbox message
*
* Processes one received message to appropriate transfer information and
* signals completion of the transfer.
*
* NOTE: This function will be invoked in IRQ context, hence should be
* as optimal as possible.
*/
static void scmi_rx_callback(struct mbox_client *cl, void *m)
{
u16 xfer_id;
struct scmi_xfer *xfer;
struct scmi_chan_info *cinfo = client_to_scmi_chan_info(cl);
struct device *dev = cinfo->dev;
struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
struct scmi_xfers_info *minfo = &info->minfo;
struct scmi_shared_mem __iomem *mem = cinfo->payload;
xfer_id = MSG_XTRACT_TOKEN(ioread32(&mem->msg_header));
/* Are we even expecting this? */
<
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