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|
// SPDX-License-Identifier: GPL-2.0
// ISHTP interface for ChromeOS Embedded Controller
//
// Copyright (c) 2019, Intel Corporation.
//
// ISHTP client driver for talking to the Chrome OS EC firmware running
// on Intel Integrated Sensor Hub (ISH) using the ISH Transport protocol
// (ISH-TP).
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/platform_data/cros_ec_commands.h>
#include <linux/platform_data/cros_ec_proto.h>
#include <linux/intel-ish-client-if.h>
/*
* ISH TX/RX ring buffer pool size
*
* The AP->ISH messages and corresponding ISH->AP responses are
* serialized. We need 1 TX and 1 RX buffer for these.
*
* The MKBP ISH->AP events are serialized. We need one additional RX
* buffer for them.
*/
#define CROS_ISH_CL_TX_RING_SIZE 8
#define CROS_ISH_CL_RX_RING_SIZE 8
/* ISH CrOS EC Host Commands */
enum cros_ec_ish_channel {
CROS_EC_COMMAND = 1, /* AP->ISH message */
CROS_MKBP_EVENT = 2, /* ISH->AP events */
};
/*
* ISH firmware timeout for 1 message send failure is 1Hz, and the
* firmware will retry 2 times, so 3Hz is used for timeout.
*/
#define ISHTP_SEND_TIMEOUT (3 * HZ)
/* ISH Transport CrOS EC ISH client unique GUID */
static const guid_t cros_ish_guid =
GUID_INIT(0x7b7154d0, 0x56f4, 0x4bdc,
0xb0, 0xd8, 0x9e, 0x7c, 0xda, 0xe0, 0xd6, 0xa0);
struct header {
u8 channel;
u8 status;
u8 reserved[2];
} __packed;
struct cros_ish_out_msg {
struct header hdr;
struct ec_host_request ec_request;
} __packed;
struct cros_ish_in_msg {
struct header hdr;
struct ec_host_response ec_response;
} __packed;
#define IN_MSG_EC_RESPONSE_PREAMBLE \
offsetof(struct cros_ish_in_msg, ec_response)
#define OUT_MSG_EC_REQUEST_PREAMBLE \
offsetof(struct cros_ish_out_msg, ec_request)
#define cl_data_to_dev(client_data) ishtp_device((client_data)->cl_device)
/*
* The Read-Write Semaphore is used to prevent message TX or RX while
* the ishtp client is being initialized or undergoing reset.
*
* The readers are the kernel function calls responsible for IA->ISH
* and ISH->AP messaging.
*
* The writers are .reset() and .probe() function.
*/
DECLARE_RWSEM(init_lock);
/**
* struct response_info - Encapsulate firmware response related
* information for passing between function ish_send() and
* process_recv() callback.
*
* @data: Copy the data received from firmware here.
* @max_size: Max size allocated for the @data buffer. If the received
* data exceeds this value, we log an error.
* @size: Actual size of data received from firmware.
* @error: 0 for success, negative error code for a failure in process_recv().
* @received: Set to true on receiving a valid firmware response to host command
* @wait_queue: Wait queue for host to wait for firmware response.
*/
struct response_info {
void *data;
size_t max_size;
size_t size;
int error;
bool received;
wait_queue_head_t wait_queue;
};
/**
* struct ishtp_cl_data - Encapsulate per ISH TP Client.
*
* @cros_ish_cl: ISHTP firmware client instance.
* @cl_device: ISHTP client device instance.
* @response: Response info passing between ish_send() and process_recv().
* @work_ishtp_reset: Work queue reset handling.
* @work_ec_evt: Work queue for EC events.
* @ec_dev: CrOS EC MFD device.
*
* This structure is used to store per client data.
*/
struct ishtp_cl_data {
struct ishtp_cl *cros_ish_cl;
struct ishtp_cl_device *cl_device;
/*
* Used for passing firmware response information between
* ish_send() and process_recv() callback.
*/
struct response_info response;
struct work_struct work_ishtp_reset;
struct work_struct work_ec_evt;
struct cros_ec_device *ec_dev;
};
/**
* ish_evt_handler - ISH to AP event handler
* @work: Work struct
*/
static void ish_evt_handler(struct work_struct *work)
{
struct ishtp_cl_data *client_data =
container_of(work, struct ishtp_cl_data, work_ec_evt);
struct cros_ec_device *ec_dev = client_data->ec_dev;
if (cros_ec_get_next_event(ec_dev, NULL) > 0) {
blocking_notifier_call_chain(&ec_dev->event_notifier,
0, ec_dev);
}
}
/**
* ish_send() - Send message from host to firmware
*
* @client_data: Client data instance
* @out_msg: Message buffer to be sent to firmware
* @out_size: Size of out going message
* @in_msg: Message buffer where the incoming data is copied. This buffer
* is allocated by calling
* @in_size: Max size of incoming message
*
* Return: Number of bytes copied in the in_msg on success, negative
* error code on failure.
*/
static int ish_send(struct ishtp_cl_data *client_data,
u8 *out_msg, size_t out_size,
u8 *in_msg, size_t in_size)
{
int rv;
struct header *out_hdr = (struct header *)out_msg;
struct ishtp_cl *cros_ish_cl = client_data->cros_ish_cl;
dev_dbg(cl_data_to_dev(client_data),
"%s: channel=%02u status=%02u\n",
__func__, out_hdr->channel, out_hdr->status);
/* Setup for incoming response */
client_data->response.data = in_msg;
client_data->response.max_size = in_size;
client_data->response.error = 0;
client_data->response.received = false;
rv = ishtp_cl_send(cros_ish_cl, out_msg, out_size);
if (rv) {
dev_err(cl_data_to_dev(client_data),
"ishtp_cl_send error %d\n", rv);
return rv;
}
wait_event_interruptible_timeout(client_data->response.wait_queue,
client_data->response.received,
ISHTP_SEND_TIMEOUT);
if (!client_data->response.received) {
dev_err(cl_data_to_dev(client_data),
"Timed out for response to host message\n");
return -ETIMEDOUT;
}
if (client_data->response.error < 0)
return client_data->response.error;
return client_data->response.size;
}
/**
* process_recv() - Received and parse incoming packet
* @cros_ish_cl: Client instance to get stats
* @rb_in_proc: Host interface message buffer
*
* Parse the incoming packet. If it is a response packet then it will
* update per instance flags and wake up the caller waiting to for the
* response. If it is an event packet then it will schedule event work.
*/
static void process_recv(struct ishtp_cl *cros_ish_cl,
struct ishtp_cl_rb *rb_in_proc)
{
size_t data_len = rb_in_proc->buf_idx;
struct ishtp_cl_data *client_data =
ishtp_get_client_data(cros_ish_cl);
struct device *dev = cl_data_to_dev(client_data);
struct cros_ish_in_msg *in_msg =
(struct cros_ish_in_msg *)rb_in_proc->buffer.data;
/* Proceed only if reset or init is not in progress */
if (!down_read_trylock(&init_lock)) {
/* Free the buffer */
ishtp_cl_io_rb_recycle(rb_in_proc);
dev_warn(dev,
"Host is not ready to receive incoming messages\n");
return;
}
/*
* All firmware messages contain a header. Check the buffer size
* before accessing elements inside.
*/
if (!rb_in_proc->buffer.data) {
dev_warn(dev, "rb_in_proc->buffer.data returned null");
client_data->response.error = -EBADMSG;
goto end_error;
}
if (data_len < sizeof(struct header)) {
dev_err(dev, "data size %zu is less than header %zu\n",
data_len, sizeof(struct header));
client_data->response.error = -EMSGSIZE;
goto end_error;
}
dev_dbg(dev, "channel=%02u status=%02u\n",
in_msg->hdr.channel, in_msg->hdr.status);
switch (in_msg->hdr.channel) {
case CROS_EC_COMMAND:
/* Sanity check */
if (!client_data->response.data) {
dev_err(dev,
"Receiving buffer is null. Should be allocated by calling function
|