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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 "queue.h"
#include "queue_policies.h"
#include "producer.h"
#include "task.h"
#include "usb-stream.h"
#include "usb_i2c.h"
#define CPRINTS(format, args...) cprints(CC_I2C, format, ## args)
#define MAX_BYTES_IN_ONE_READING 254
USB_I2C_CONFIG(i2c,
USB_IFACE_I2C,
USB_STR_I2C_NAME,
USB_EP_I2C)
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);
}
}
static uint8_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)
{
/*
* In order to support larger write payload, we need to peek
* the queue to see if we need to wait for more data.
*/
uint8_t write_count;
if (queue_peek_units(config->consumer.queue, &write_count, 2, 1) == 1
&& (write_count + 4) > queue_count(config->consumer.queue)) {
/*
* Feed me more data, please.
* Reuse the buffer in usb_i2c_config to send ACK packet.
*/
config->buffer[0] = USB_I2C_SUCCESS;
config->buffer[1] = 0;
usb_i2c_write_packet(config, 4);
return 0;
}
return 1;
}
void usb_i2c_execute(struct usb_i2c_config const *config)
{
/* Payload is ready to execute. */
uint8_t count = usb_i2c_read_packet(config);
int portindex = (config->buffer[0] >> 0) & 0xff;
/* Convert 7-bit slave address to chromium EC 8-bit address. */
uint8_t slave_addr = (config->buffer[0] >> 7) & 0xfe;
int write_count = (config->buffer[1] >> 0) & 0xff;
int read_count = (config->buffer[1] >> 8) & 0xff;
uint8_t *payload = (uint8_t *)(config->buffer + 2);
int xfer_flag = I2C_XFER_START;
int offset = 0; /* Offset for extended reading header. */
int rv = 0;
int complete_bytes = 0;
int bytes_to_read, port;
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 {
/*
* 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.
*/
port = i2c_ports[portindex].port;
/*
* Because The I2C_XFER_SINGLE might limit the reading to be
* less than 255 bytes (For example, register design of
* STM32_I2C_CR2 in i2c-stm32f0.c), we hold the STOP bits for
* reading request larger than 255 bytes.
*/
do {
bytes_to_read = read_count - complete_bytes;
if (bytes_to_read > MAX_BYTES_IN_ONE_READING)
bytes_to_read = MAX_BYTES_IN_ONE_READING;
else
xfer_flag |= I2C_XFER_STOP;
rv = i2c_xfer(
port, slave_addr,
complete_bytes ? NULL : payload + offset,
complete_bytes ? 0 : write_count,
payload + complete_bytes,
bytes_to_read, xfer_flag);
complete_bytes += bytes_to_read;
xfer_flag = 0;
} while (complete_bytes < read_count && !rv);
config->buffer[0] = usb_i2c_map_error(rv);
}
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);
}
static void usb_i2c_flush(struct consumer const *consumer)
{
}
struct consumer_ops const usb_i2c_consumer_ops = {
.written = usb_i2c_written,
.flush = usb_i2c_flush,
};
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