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/* Copyright 2016 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "common.h"
#include "link_defs.h"
#include "registers.h"
#include "i2c.h"
#include "usb_descriptor.h"
#include "util.h"
#include "common.h"
#include "console.h"
#include "consumer.h"
#include "producer.h"
#include "queue.h"
#include "queue_policies.h"
#include "task.h"
#include "usb-stream.h"
#include "usb_i2c.h"
#define CPRINTS(format, args...) cprints(CC_I2C, format, ## args)
USB_I2C_CONFIG(i2c,
USB_IFACE_I2C,
USB_STR_I2C_NAME,
USB_EP_I2C)
static int (*cros_cmd_handler)(void *data_in,
size_t in_size,
void *data_out,
size_t out_size);
static int16_t usb_i2c_map_error(int error)
{
switch (error) {
case EC_SUCCESS: return USB_I2C_SUCCESS;
case EC_ERROR_TIMEOUT: return USB_I2C_TIMEOUT;
case EC_ERROR_BUSY: return USB_I2C_BUSY;
default: return USB_I2C_UNKNOWN_ERROR | (error & 0x7fff);
}
}
/*
* Return value should be large enough to accommodate the entire read queue
* buffer size. Let's use 4 bytes in case future designs have a lot of RAM and
* allow for large buffers.
*/
static uint32_t usb_i2c_read_packet(struct usb_i2c_config const *config)
{
return QUEUE_REMOVE_UNITS(config->consumer.queue, config->buffer,
queue_count(config->consumer.queue));
}
static void usb_i2c_write_packet(struct usb_i2c_config const *config,
size_t count)
{
QUEUE_ADD_UNITS(config->tx_queue, config->buffer, count);
}
static uint8_t usb_i2c_executable(struct usb_i2c_config const *config)
{
static size_t expected_size;
if (!expected_size) {
uint8_t peek[4];
/*
* In order to support larger write payload, we need to peek
* the queue to see if we need to wait for more data.
*/
if (queue_peek_units(config->consumer.queue,
peek, 0, sizeof(peek))
!= sizeof(peek)) {
/* Not enough data to calculate expected_size. */
return 0;
}
/*
* The first four bytes of the packet will describe its
* expected size.
*/
/* Header bytes and extra rc bytes, if present. */
if (peek[3] & 0x80)
expected_size = 6;
else
expected_size = 4;
/* write count */
expected_size += (((size_t)peek[0] & 0xf0) << 4) | peek[2];
}
if (queue_count(config->consumer.queue) >= expected_size) {
expected_size = 0;
return 1;
}
return 0;
}
static void usb_i2c_execute(struct usb_i2c_config const *config)
{
/* Payload is ready to execute. */
uint32_t count = usb_i2c_read_packet(config);
int portindex = (config->buffer[0] >> 0) & 0xf;
uint16_t addr_flags = (config->buffer[0] >> 8) & 0x7f;
int write_count = ((config->buffer[0] << 4) & 0xf00) |
((config->buffer[1] >> 0) & 0xff);
int read_count = (config->buffer[1] >> 8) & 0xff;
int offset = 0; /* Offset for extended reading header. */
config->buffer[0] = 0;
config->buffer[1] = 0;
if (read_count & 0x80) {
read_count = ((config->buffer[2] & 0xff) << 7) |
(read_count & 0x7f);
offset = 2;
}
if (!count || (!read_count && !write_count))
return;
if (!usb_i2c_board_is_enabled()) {
config->buffer[0] = USB_I2C_DISABLED;
} else if (write_count > CONFIG_USB_I2C_MAX_WRITE_COUNT ||
write_count != (count - 4 - offset)) {
config->buffer[0] = USB_I2C_WRITE_COUNT_INVALID;
} else if (read_count > CONFIG_USB_I2C_MAX_READ_COUNT) {
config->buffer[0] = USB_I2C_READ_COUNT_INVALID;
} else if (portindex >= i2c_ports_used) {
config->buffer[0] = USB_I2C_PORT_INVALID;
} else if (addr_flags == USB_I2C_CMD_ADDR_FLAGS) {
/*
* This is a non-i2c command, invoke the handler if it has
* been registered, if not - report the appropriate error.
*/
if (!cros_cmd_handler)
config->buffer[0] = USB_I2C_MISSING_HANDLER;
else
config->buffer[0] = cros_cmd_handler(config->buffer + 2,
write_count,
config->buffer + 2,
read_count);
} else {
int ret;
/*
* TODO (crbug.com/750397): Add security. This currently
* blindly passes through ALL I2C commands on any bus the EC
* knows about. It should behave closer to
* EC_CMD_I2C_PASSTHRU, which can protect ports and ranges.
*/
ret = i2c_xfer(i2c_ports[portindex].port, addr_flags,
(uint8_t *)(config->buffer + 2) + offset,
write_count,
(uint8_t *)(config->buffer + 2),
read_count);
config->buffer[0] = usb_i2c_map_error(ret);
}
usb_i2c_write_packet(config, read_count + 4);
}
void usb_i2c_deferred(struct usb_i2c_config const *config)
{
/* Check if we can proceed the queue. */
if (usb_i2c_executable(config))
usb_i2c_execute(config);
}
static void usb_i2c_written(struct consumer const *consumer, size_t count)
{
struct usb_i2c_config const *config =
DOWNCAST(consumer, struct usb_i2c_config, consumer);
hook_call_deferred(config->deferred, 0);
}
struct consumer_ops const usb_i2c_consumer_ops = {
.written = usb_i2c_written,
};
int usb_i2c_register_cros_cmd_handler(int (*cmd_handler)
(void *data_in,
size_t in_size,
void *data_out,
size_t out_size))
{
if (cros_cmd_handler)
return -1;
cros_cmd_handler = cmd_handler;
return 0;
}
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