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- #include <linux/delay.h>
- #include <linux/kernel.h>
- #include <linux/module.h>
- #include <linux/mfd/cros_ec.h>
- #include <linux/mfd/cros_ec_commands.h>
- #include <linux/of.h>
- #include <linux/platform_device.h>
- #include <linux/slab.h>
- #include <linux/spi/spi.h>
- #define EC_MSG_HEADER 0xec
- #define EC_MSG_PREAMBLE_COUNT 32
- #define EC_MSG_DEADLINE_MS 100
- #define EC_SPI_RECOVERY_TIME_NS (200 * 1000)
- struct cros_ec_spi {
- struct spi_device *spi;
- s64 last_transfer_ns;
- unsigned int start_of_msg_delay;
- unsigned int end_of_msg_delay;
- };
- static void debug_packet(struct device *dev, const char *name, u8 *ptr,
- int len)
- {
- #ifdef DEBUG
- int i;
- dev_dbg(dev, "%s: ", name);
- for (i = 0; i < len; i++)
- pr_cont(" %02x", ptr[i]);
- pr_cont("\n");
- #endif
- }
- static int terminate_request(struct cros_ec_device *ec_dev)
- {
- struct cros_ec_spi *ec_spi = ec_dev->priv;
- struct spi_message msg;
- struct spi_transfer trans;
- int ret;
-
- spi_message_init(&msg);
- memset(&trans, 0, sizeof(trans));
- trans.delay_usecs = ec_spi->end_of_msg_delay;
- spi_message_add_tail(&trans, &msg);
- ret = spi_sync_locked(ec_spi->spi, &msg);
-
- ec_spi->last_transfer_ns = ktime_get_ns();
- if (ret < 0) {
- dev_err(ec_dev->dev,
- "cs-deassert spi transfer failed: %d\n",
- ret);
- }
- return ret;
- }
- static int receive_n_bytes(struct cros_ec_device *ec_dev, u8 *buf, int n)
- {
- struct cros_ec_spi *ec_spi = ec_dev->priv;
- struct spi_transfer trans;
- struct spi_message msg;
- int ret;
- BUG_ON(buf - ec_dev->din + n > ec_dev->din_size);
- memset(&trans, 0, sizeof(trans));
- trans.cs_change = 1;
- trans.rx_buf = buf;
- trans.len = n;
- spi_message_init(&msg);
- spi_message_add_tail(&trans, &msg);
- ret = spi_sync_locked(ec_spi->spi, &msg);
- if (ret < 0)
- dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
- return ret;
- }
- static int cros_ec_spi_receive_packet(struct cros_ec_device *ec_dev,
- int need_len)
- {
- struct ec_host_response *response;
- u8 *ptr, *end;
- int ret;
- unsigned long deadline;
- int todo;
- BUG_ON(ec_dev->din_size < EC_MSG_PREAMBLE_COUNT);
-
- deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS);
- while (true) {
- unsigned long start_jiffies = jiffies;
- ret = receive_n_bytes(ec_dev,
- ec_dev->din,
- EC_MSG_PREAMBLE_COUNT);
- if (ret < 0)
- return ret;
- ptr = ec_dev->din;
- for (end = ptr + EC_MSG_PREAMBLE_COUNT; ptr != end; ptr++) {
- if (*ptr == EC_SPI_FRAME_START) {
- dev_dbg(ec_dev->dev, "msg found at %zd\n",
- ptr - ec_dev->din);
- break;
- }
- }
- if (ptr != end)
- break;
-
- if (time_after(start_jiffies, deadline)) {
- dev_warn(ec_dev->dev, "EC failed to respond in time\n");
- return -ETIMEDOUT;
- }
- }
-
- todo = end - ++ptr;
- BUG_ON(todo < 0 || todo > ec_dev->din_size);
- todo = min(todo, need_len);
- memmove(ec_dev->din, ptr, todo);
- ptr = ec_dev->din + todo;
- dev_dbg(ec_dev->dev, "need %d, got %d bytes from preamble\n",
- need_len, todo);
- need_len -= todo;
-
- if (todo < sizeof(*response)) {
- ret = receive_n_bytes(ec_dev, ptr, sizeof(*response) - todo);
- if (ret < 0)
- return -EBADMSG;
- ptr += (sizeof(*response) - todo);
- todo = sizeof(*response);
- }
- response = (struct ec_host_response *)ec_dev->din;
-
- if (response->data_len > ec_dev->din_size)
- return -EMSGSIZE;
-
- while (need_len > 0) {
-
- todo = min(need_len, 256);
- dev_dbg(ec_dev->dev, "loop, todo=%d, need_len=%d, ptr=%zd\n",
- todo, need_len, ptr - ec_dev->din);
- ret = receive_n_bytes(ec_dev, ptr, todo);
- if (ret < 0)
- return ret;
- ptr += todo;
- need_len -= todo;
- }
- dev_dbg(ec_dev->dev, "loop done, ptr=%zd\n", ptr - ec_dev->din);
- return 0;
- }
- static int cros_ec_spi_receive_response(struct cros_ec_device *ec_dev,
- int need_len)
- {
- u8 *ptr, *end;
- int ret;
- unsigned long deadline;
- int todo;
- BUG_ON(ec_dev->din_size < EC_MSG_PREAMBLE_COUNT);
-
- deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS);
- while (true) {
- unsigned long start_jiffies = jiffies;
- ret = receive_n_bytes(ec_dev,
- ec_dev->din,
- EC_MSG_PREAMBLE_COUNT);
- if (ret < 0)
- return ret;
- ptr = ec_dev->din;
- for (end = ptr + EC_MSG_PREAMBLE_COUNT; ptr != end; ptr++) {
- if (*ptr == EC_SPI_FRAME_START) {
- dev_dbg(ec_dev->dev, "msg found at %zd\n",
- ptr - ec_dev->din);
- break;
- }
- }
- if (ptr != end)
- break;
-
- if (time_after(start_jiffies, deadline)) {
- dev_warn(ec_dev->dev, "EC failed to respond in time\n");
- return -ETIMEDOUT;
- }
- }
-
- todo = end - ++ptr;
- BUG_ON(todo < 0 || todo > ec_dev->din_size);
- todo = min(todo, need_len);
- memmove(ec_dev->din, ptr, todo);
- ptr = ec_dev->din + todo;
- dev_dbg(ec_dev->dev, "need %d, got %d bytes from preamble\n",
- need_len, todo);
- need_len -= todo;
-
- while (need_len > 0) {
-
- todo = min(need_len, 256);
- dev_dbg(ec_dev->dev, "loop, todo=%d, need_len=%d, ptr=%zd\n",
- todo, need_len, ptr - ec_dev->din);
- ret = receive_n_bytes(ec_dev, ptr, todo);
- if (ret < 0)
- return ret;
- debug_packet(ec_dev->dev, "interim", ptr, todo);
- ptr += todo;
- need_len -= todo;
- }
- dev_dbg(ec_dev->dev, "loop done, ptr=%zd\n", ptr - ec_dev->din);
- return 0;
- }
- static int cros_ec_pkt_xfer_spi(struct cros_ec_device *ec_dev,
- struct cros_ec_command *ec_msg)
- {
- struct ec_host_response *response;
- struct cros_ec_spi *ec_spi = ec_dev->priv;
- struct spi_transfer trans, trans_delay;
- struct spi_message msg;
- int i, len;
- u8 *ptr;
- u8 *rx_buf;
- u8 sum;
- int ret = 0, final_ret;
- len = cros_ec_prepare_tx(ec_dev, ec_msg);
- dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
-
- if (ec_spi->last_transfer_ns) {
- unsigned long delay;
- delay = ktime_get_ns() - ec_spi->last_transfer_ns;
- if (delay < EC_SPI_RECOVERY_TIME_NS)
- ndelay(EC_SPI_RECOVERY_TIME_NS - delay);
- }
- rx_buf = kzalloc(len, GFP_KERNEL);
- if (!rx_buf)
- return -ENOMEM;
- spi_bus_lock(ec_spi->spi->master);
-
- spi_message_init(&msg);
- if (ec_spi->start_of_msg_delay) {
- memset(&trans_delay, 0, sizeof(trans_delay));
- trans_delay.delay_usecs = ec_spi->start_of_msg_delay;
- spi_message_add_tail(&trans_delay, &msg);
- }
-
- memset(&trans, 0, sizeof(trans));
- trans.tx_buf = ec_dev->dout;
- trans.rx_buf = rx_buf;
- trans.len = len;
- trans.cs_change = 1;
- spi_message_add_tail(&trans, &msg);
- ret = spi_sync_locked(ec_spi->spi, &msg);
-
- if (!ret) {
-
- for (i = 0; i < len; i++) {
- switch (rx_buf[i]) {
- case EC_SPI_PAST_END:
- case EC_SPI_RX_BAD_DATA:
- case EC_SPI_NOT_READY:
- ret = -EAGAIN;
- ec_msg->result = EC_RES_IN_PROGRESS;
- default:
- break;
- }
- if (ret)
- break;
- }
- if (!ret)
- ret = cros_ec_spi_receive_packet(ec_dev,
- ec_msg->insize + sizeof(*response));
- } else {
- dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
- }
- final_ret = terminate_request(ec_dev);
- spi_bus_unlock(ec_spi->spi->master);
- if (!ret)
- ret = final_ret;
- if (ret < 0)
- goto exit;
- ptr = ec_dev->din;
-
- response = (struct ec_host_response *)ptr;
- ec_msg->result = response->result;
- ret = cros_ec_check_result(ec_dev, ec_msg);
- if (ret)
- goto exit;
- len = response->data_len;
- sum = 0;
- if (len > ec_msg->insize) {
- dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
- len, ec_msg->insize);
- ret = -EMSGSIZE;
- goto exit;
- }
- for (i = 0; i < sizeof(*response); i++)
- sum += ptr[i];
-
- memcpy(ec_msg->data, ptr + sizeof(*response), len);
- for (i = 0; i < len; i++)
- sum += ec_msg->data[i];
- if (sum) {
- dev_err(ec_dev->dev,
- "bad packet checksum, calculated %x\n",
- sum);
- ret = -EBADMSG;
- goto exit;
- }
- ret = len;
- exit:
- kfree(rx_buf);
- if (ec_msg->command == EC_CMD_REBOOT_EC)
- msleep(EC_REBOOT_DELAY_MS);
- return ret;
- }
- static int cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev,
- struct cros_ec_command *ec_msg)
- {
- struct cros_ec_spi *ec_spi = ec_dev->priv;
- struct spi_transfer trans;
- struct spi_message msg;
- int i, len;
- u8 *ptr;
- u8 *rx_buf;
- int sum;
- int ret = 0, final_ret;
- len = cros_ec_prepare_tx(ec_dev, ec_msg);
- dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
-
- if (ec_spi->last_transfer_ns) {
- unsigned long delay;
- delay = ktime_get_ns() - ec_spi->last_transfer_ns;
- if (delay < EC_SPI_RECOVERY_TIME_NS)
- ndelay(EC_SPI_RECOVERY_TIME_NS - delay);
- }
- rx_buf = kzalloc(len, GFP_KERNEL);
- if (!rx_buf)
- return -ENOMEM;
- spi_bus_lock(ec_spi->spi->master);
-
- debug_packet(ec_dev->dev, "out", ec_dev->dout, len);
- memset(&trans, 0, sizeof(trans));
- trans.tx_buf = ec_dev->dout;
- trans.rx_buf = rx_buf;
- trans.len = len;
- trans.cs_change = 1;
- spi_message_init(&msg);
- spi_message_add_tail(&trans, &msg);
- ret = spi_sync_locked(ec_spi->spi, &msg);
-
- if (!ret) {
-
- for (i = 0; i < len; i++) {
- switch (rx_buf[i]) {
- case EC_SPI_PAST_END:
- case EC_SPI_RX_BAD_DATA:
- case EC_SPI_NOT_READY:
- ret = -EAGAIN;
- ec_msg->result = EC_RES_IN_PROGRESS;
- default:
- break;
- }
- if (ret)
- break;
- }
- if (!ret)
- ret = cros_ec_spi_receive_response(ec_dev,
- ec_msg->insize + EC_MSG_TX_PROTO_BYTES);
- } else {
- dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
- }
- final_ret = terminate_request(ec_dev);
- spi_bus_unlock(ec_spi->spi->master);
- if (!ret)
- ret = final_ret;
- if (ret < 0)
- goto exit;
- ptr = ec_dev->din;
-
- ec_msg->result = ptr[0];
- ret = cros_ec_check_result(ec_dev, ec_msg);
- if (ret)
- goto exit;
- len = ptr[1];
- sum = ptr[0] + ptr[1];
- if (len > ec_msg->insize) {
- dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
- len, ec_msg->insize);
- ret = -ENOSPC;
- goto exit;
- }
-
- for (i = 0; i < len; i++) {
- sum += ptr[i + 2];
- if (ec_msg->insize)
- ec_msg->data[i] = ptr[i + 2];
- }
- sum &= 0xff;
- debug_packet(ec_dev->dev, "in", ptr, len + 3);
- if (sum != ptr[len + 2]) {
- dev_err(ec_dev->dev,
- "bad packet checksum, expected %02x, got %02x\n",
- sum, ptr[len + 2]);
- ret = -EBADMSG;
- goto exit;
- }
- ret = len;
- exit:
- kfree(rx_buf);
- if (ec_msg->command == EC_CMD_REBOOT_EC)
- msleep(EC_REBOOT_DELAY_MS);
- return ret;
- }
- static void cros_ec_spi_dt_probe(struct cros_ec_spi *ec_spi, struct device *dev)
- {
- struct device_node *np = dev->of_node;
- u32 val;
- int ret;
- ret = of_property_read_u32(np, "google,cros-ec-spi-pre-delay", &val);
- if (!ret)
- ec_spi->start_of_msg_delay = val;
- ret = of_property_read_u32(np, "google,cros-ec-spi-msg-delay", &val);
- if (!ret)
- ec_spi->end_of_msg_delay = val;
- }
- static int cros_ec_spi_probe(struct spi_device *spi)
- {
- struct device *dev = &spi->dev;
- struct cros_ec_device *ec_dev;
- struct cros_ec_spi *ec_spi;
- int err;
- spi->bits_per_word = 8;
- spi->mode = SPI_MODE_0;
- err = spi_setup(spi);
- if (err < 0)
- return err;
- ec_spi = devm_kzalloc(dev, sizeof(*ec_spi), GFP_KERNEL);
- if (ec_spi == NULL)
- return -ENOMEM;
- ec_spi->spi = spi;
- ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
- if (!ec_dev)
- return -ENOMEM;
-
- cros_ec_spi_dt_probe(ec_spi, dev);
- spi_set_drvdata(spi, ec_dev);
- ec_dev->dev = dev;
- ec_dev->priv = ec_spi;
- ec_dev->irq = spi->irq;
- ec_dev->cmd_xfer = cros_ec_cmd_xfer_spi;
- ec_dev->pkt_xfer = cros_ec_pkt_xfer_spi;
- ec_dev->phys_name = dev_name(&ec_spi->spi->dev);
- ec_dev->din_size = EC_MSG_PREAMBLE_COUNT +
- sizeof(struct ec_host_response) +
- sizeof(struct ec_response_get_protocol_info);
- ec_dev->dout_size = sizeof(struct ec_host_request);
- ec_spi->last_transfer_ns = ktime_get_ns();
- err = cros_ec_register(ec_dev);
- if (err) {
- dev_err(dev, "cannot register EC\n");
- return err;
- }
- device_init_wakeup(&spi->dev, true);
- return 0;
- }
- static int cros_ec_spi_remove(struct spi_device *spi)
- {
- struct cros_ec_device *ec_dev;
- ec_dev = spi_get_drvdata(spi);
- cros_ec_remove(ec_dev);
- return 0;
- }
- #ifdef CONFIG_PM_SLEEP
- static int cros_ec_spi_suspend(struct device *dev)
- {
- struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
- return cros_ec_suspend(ec_dev);
- }
- static int cros_ec_spi_resume(struct device *dev)
- {
- struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
- return cros_ec_resume(ec_dev);
- }
- #endif
- static SIMPLE_DEV_PM_OPS(cros_ec_spi_pm_ops, cros_ec_spi_suspend,
- cros_ec_spi_resume);
- static const struct of_device_id cros_ec_spi_of_match[] = {
- { .compatible = "google,cros-ec-spi", },
- { },
- };
- MODULE_DEVICE_TABLE(of, cros_ec_spi_of_match);
- static const struct spi_device_id cros_ec_spi_id[] = {
- { "cros-ec-spi", 0 },
- { }
- };
- MODULE_DEVICE_TABLE(spi, cros_ec_spi_id);
- static struct spi_driver cros_ec_driver_spi = {
- .driver = {
- .name = "cros-ec-spi",
- .of_match_table = of_match_ptr(cros_ec_spi_of_match),
- .pm = &cros_ec_spi_pm_ops,
- },
- .probe = cros_ec_spi_probe,
- .remove = cros_ec_spi_remove,
- .id_table = cros_ec_spi_id,
- };
- module_spi_driver(cros_ec_driver_spi);
- MODULE_LICENSE("GPL v2");
- MODULE_DESCRIPTION("ChromeOS EC multi function device (SPI)");
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