diff options
Diffstat (limited to 'chip/stm32/usb_i2c.c')
| -rw-r--r-- | chip/stm32/usb_i2c.c | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/chip/stm32/usb_i2c.c b/chip/stm32/usb_i2c.c new file mode 100644 index 0000000000..1cc13bc304 --- /dev/null +++ b/chip/stm32/usb_i2c.c @@ -0,0 +1,140 @@ +/* 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 "usb_i2c.h" +#include "util.h" + +#define CPRINTS(format, args...) cprints(CC_I2C, format, ## args) + + +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) +{ + size_t i; + uint16_t bytes = btable_ep[config->endpoint].rx_count & 0x3ff; + size_t count = MAX((bytes + 1) / 2, USB_MAX_PACKET_SIZE / 2); + + /* + * The USB peripheral doesn't support DMA access to its packet + * RAM so we have to copy messages out into a bounce buffer. + */ + for (i = 0; i < count; ++i) + config->buffer[i] = config->rx_ram[i]; + + /* + * RX packet consumed, mark the packet as VALID. The master + * could queue up the next command while we process this I2C + * transaction and prepare the response. + */ + STM32_TOGGLE_EP(config->endpoint, EP_RX_MASK, EP_RX_VALID, 0); + + return bytes; +} + +static void usb_i2c_write_packet(struct usb_i2c_config const *config, + uint8_t count) +{ + size_t i; + /* count is bounds checked in usb_i2c_deferred. */ + + /* + * Copy read bytes and status back out of bounce buffer and + * update TX packet state (mark as VALID for master to read). + */ + for (i = 0; i < (count + 1) / 2; ++i) + config->tx_ram[i] = config->buffer[i]; + + btable_ep[config->endpoint].tx_count = count; + + STM32_TOGGLE_EP(config->endpoint, EP_TX_MASK, EP_TX_VALID, 0); +} + +static int rx_valid(struct usb_i2c_config const *config) +{ + return (STM32_USB_EP(config->endpoint) & EP_RX_MASK) == EP_RX_VALID; +} + +void usb_i2c_deferred(struct usb_i2c_config const *config) +{ + /* + * And if there is a USB packet waiting we process it and generate a + * response. + */ + if (!rx_valid(config)) { + uint16_t count = usb_i2c_read_packet(config); + int portindex = (config->buffer[0] >> 0) & 0xff; + + /* Convert 7-bit slave address to stm32 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; + int port = 0; + + config->buffer[0] = 0; + config->buffer[1] = 0; + + if (write_count > USB_I2C_MAX_WRITE_COUNT || + write_count != (count - 4)) { + config->buffer[0] = USB_I2C_WRITE_COUNT_INVALID; + } else if (read_count > 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 { + port = i2c_ports[portindex].port; + config->buffer[0] = usb_i2c_map_error( + i2c_xfer(port, slave_addr, + (uint8_t *)(config->buffer + 2), + write_count, + (uint8_t *)(config->buffer + 2), + read_count, I2C_XFER_SINGLE)); + } + + usb_i2c_write_packet(config, read_count + 4); + } +} + +void usb_i2c_tx(struct usb_i2c_config const *config) +{ + STM32_TOGGLE_EP(config->endpoint, EP_TX_MASK, EP_TX_NAK, 0); +} + +void usb_i2c_rx(struct usb_i2c_config const *config) +{ + STM32_TOGGLE_EP(config->endpoint, EP_RX_MASK, EP_RX_NAK, 0); + + hook_call_deferred(config->deferred, 0); +} + +void usb_i2c_reset(struct usb_i2c_config const *config) +{ + int endpoint = config->endpoint; + + btable_ep[endpoint].tx_addr = usb_sram_addr(config->tx_ram); + btable_ep[endpoint].tx_count = 0; + + btable_ep[endpoint].rx_addr = usb_sram_addr(config->rx_ram); + btable_ep[endpoint].rx_count = + 0x8000 | ((USB_MAX_PACKET_SIZE / 32 - 1) << 10); + + STM32_USB_EP(endpoint) = ((endpoint << 0) | /* Endpoint Addr*/ + (2 << 4) | /* TX NAK */ + (0 << 9) | /* Bulk EP */ + (3 << 12)); /* RX Valid */ +} |