--- zzzz-none-000/linux-3.10.107/drivers/mfd/cros_ec_spi.c 2017-06-27 09:49:32.000000000 +0000 +++ scorpion-7490-727/linux-3.10.107/drivers/mfd/cros_ec_spi.c 2021-02-04 17:41:59.000000000 +0000 @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -38,22 +39,31 @@ #define EC_MSG_PREAMBLE_COUNT 32 /* - * We must get a response from the EC in 5ms. This is a very long - * time, but the flash write command can take 2-3ms. The EC command - * processing is currently not very fast (about 500us). We could - * look at speeding this up and making the flash write command a - * 'slow' command, requiring a GET_STATUS wait loop, like flash - * erase. - */ -#define EC_MSG_DEADLINE_MS 5 + * Allow for a long time for the EC to respond. We support i2c + * tunneling and support fairly long messages for the tunnel (249 + * bytes long at the moment). If we're talking to a 100 kHz device + * on the other end and need to transfer ~256 bytes, then we need: + * 10 us/bit * ~10 bits/byte * ~256 bytes = ~25ms + * + * We'll wait 4 times that to handle clock stretching and other + * paranoia. + * + * It's pretty unlikely that we'll really see a 249 byte tunnel in + * anything other than testing. If this was more common we might + * consider having slow commands like this require a GET_STATUS + * wait loop. The 'flash write' command would be another candidate + * for this, clocking in at 2-3ms. + */ +#define EC_MSG_DEADLINE_MS 100 /* * Time between raising the SPI chip select (for the end of a * transaction) and dropping it again (for the next transaction). - * If we go too fast, the EC will miss the transaction. It seems - * that 50us is enough with the 16MHz STM32 EC. + * If we go too fast, the EC will miss the transaction. We know that we + * need at least 70 us with the 16 MHz STM32 EC, so go with 200 us to be + * safe. */ -#define EC_SPI_RECOVERY_TIME_NS (50 * 1000) +#define EC_SPI_RECOVERY_TIME_NS (200 * 1000) /** * struct cros_ec_spi - information about a SPI-connected EC @@ -61,24 +71,198 @@ * @spi: SPI device we are connected to * @last_transfer_ns: time that we last finished a transfer, or 0 if there * if no record + * @start_of_msg_delay: used to set the delay_usecs on the spi_transfer that + * is sent when we want to turn on CS at the start of a transaction. + * @end_of_msg_delay: used to set the delay_usecs on the spi_transfer that + * is sent when we want to turn off CS at the end of a transaction. */ 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) + int len) { #ifdef DEBUG int i; dev_dbg(dev, "%s: ", name); for (i = 0; i < len; i++) - dev_cont(dev, " %02x", ptr[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; + + /* + * Turn off CS, possibly adding a delay to ensure the rising edge + * doesn't come too soon after the end of the data. + */ + 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(ec_spi->spi, &msg); + + /* Reset end-of-response timer */ + 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; +} + +/** + * receive_n_bytes - receive n bytes from the EC. + * + * Assumes buf is a pointer into the ec_dev->din buffer + */ +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(ec_spi->spi, &msg); + if (ret < 0) + dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret); + + return ret; +} + +/** + * cros_ec_spi_receive_packet - Receive a packet from the EC. + * + * This function has two phases: reading the preamble bytes (since if we read + * data from the EC before it is ready to send, we just get preamble) and + * reading the actual message. + * + * The received data is placed into ec_dev->din. + * + * @ec_dev: ChromeOS EC device + * @need_len: Number of message bytes we need to read + */ +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_MSG_PREAMBLE_COUNT > ec_dev->din_size); + + /* Receive data until we see the header byte */ + 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; + + /* + * Use the time at the start of the loop as a timeout. This + * gives us one last shot at getting the transfer and is useful + * in case we got context switched out for a while. + */ + if (time_after(start_jiffies, deadline)) { + dev_warn(ec_dev->dev, "EC failed to respond in time\n"); + return -ETIMEDOUT; + } + } + + /* + * ptr now points to the header byte. Copy any valid data to the + * start of our buffer + */ + 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 the entire response struct wasn't read, get the rest of it. */ + 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; + + /* Abort if data_len is too large. */ + if (response->data_len > ec_dev->din_size) + return -EMSGSIZE; + + /* Receive data until we have it all */ + while (need_len > 0) { + /* + * We can't support transfers larger than the SPI FIFO size + * unless we have DMA. We don't have DMA on the ISP SPI ports + * for Exynos. We need a way of asking SPI driver for + * maximum-supported transfer size. + */ + 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; +} + /** * cros_ec_spi_receive_response - Receive a response from the EC. * @@ -94,43 +278,45 @@ static int cros_ec_spi_receive_response(struct cros_ec_device *ec_dev, int need_len) { - struct cros_ec_spi *ec_spi = ec_dev->priv; - struct spi_transfer trans; - struct spi_message msg; u8 *ptr, *end; int ret; unsigned long deadline; int todo; + BUG_ON(EC_MSG_PREAMBLE_COUNT > ec_dev->din_size); + /* Receive data until we see the header byte */ deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS); - do { - memset(&trans, '\0', sizeof(trans)); - trans.cs_change = 1; - trans.rx_buf = ptr = ec_dev->din; - trans.len = EC_MSG_PREAMBLE_COUNT; - - spi_message_init(&msg); - spi_message_add_tail(&trans, &msg); - ret = spi_sync(ec_spi->spi, &msg); - if (ret < 0) { - dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret); + 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_MSG_HEADER) { + 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(jiffies, deadline)) { + /* + * Use the time at the start of the loop as a timeout. This + * gives us one last shot at getting the transfer and is useful + * in case we got context switched out for a while. + */ + if (time_after(start_jiffies, deadline)) { dev_warn(ec_dev->dev, "EC failed to respond in time\n"); return -ETIMEDOUT; } - } while (ptr == end); + } /* * ptr now points to the header byte. Copy any valid data to the @@ -157,21 +343,9 @@ dev_dbg(ec_dev->dev, "loop, todo=%d, need_len=%d, ptr=%zd\n", todo, need_len, ptr - ec_dev->din); - memset(&trans, '\0', sizeof(trans)); - trans.cs_change = 1; - trans.rx_buf = ptr; - trans.len = todo; - spi_message_init(&msg); - spi_message_add_tail(&trans, &msg); - - /* send command to EC and read answer */ - BUG_ON((u8 *)trans.rx_buf - ec_dev->din + todo > - ec_dev->din_size); - ret = spi_sync(ec_spi->spi, &msg); - if (ret < 0) { - dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret); + ret = receive_n_bytes(ec_dev, ptr, todo); + if (ret < 0) return ret; - } debug_packet(ec_dev->dev, "interim", ptr, todo); ptr += todo; @@ -184,41 +358,178 @@ } /** - * cros_ec_command_spi_xfer - Transfer a message over SPI and receive the reply + * cros_ec_pkt_xfer_spi - Transfer a packet over SPI and receive the reply + * + * @ec_dev: ChromeOS EC device + * @ec_msg: Message to transfer + */ +static int cros_ec_pkt_xfer_spi(struct cros_ec_device *ec_dev, + struct cros_ec_command *ec_msg) +{ + struct ec_host_request *request; + 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); + request = (struct ec_host_request *)ec_dev->dout; + dev_dbg(ec_dev->dev, "prepared, len=%d\n", len); + + /* If it's too soon to do another transaction, wait */ + if (ec_spi->last_transfer_ns) { + unsigned long delay; /* The delay completed so far */ + + 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) { + ret = -ENOMEM; + goto exit; + } + + /* + * Leave a gap between CS assertion and clocking of data to allow the + * EC time to wakeup. + */ + 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); + } + + /* Transmit phase - send our message */ + 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(ec_spi->spi, &msg); + + /* Get the response */ + if (!ret) { + /* Verify that EC can process command */ + 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); + if (!ret) + ret = final_ret; + if (ret < 0) + goto exit; + + ptr = ec_dev->din; + + /* check response error code */ + 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]; + + /* copy response packet payload and compute checksum */ + 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; +} + +/** + * cros_ec_cmd_xfer_spi - Transfer a message over SPI and receive the reply * * @ec_dev: ChromeOS EC device * @ec_msg: Message to transfer */ -static int cros_ec_command_spi_xfer(struct cros_ec_device *ec_dev, - struct cros_ec_msg *ec_msg) +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; - struct timespec ts; len = cros_ec_prepare_tx(ec_dev, ec_msg); dev_dbg(ec_dev->dev, "prepared, len=%d\n", len); /* If it's too soon to do another transaction, wait */ if (ec_spi->last_transfer_ns) { - struct timespec ts; unsigned long delay; /* The delay completed so far */ - ktime_get_ts(&ts); - delay = timespec_to_ns(&ts) - ec_spi->last_transfer_ns; + delay = ktime_get_ns() - ec_spi->last_transfer_ns; if (delay < EC_SPI_RECOVERY_TIME_NS) - ndelay(delay); + ndelay(EC_SPI_RECOVERY_TIME_NS - delay); + } + + rx_buf = kzalloc(len, GFP_KERNEL); + if (!rx_buf) { + ret = -ENOMEM; + goto exit; } /* Transmit phase - send our message */ debug_packet(ec_dev->dev, "out", ec_dev->dout, len); - memset(&trans, '\0', sizeof(trans)); + 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); @@ -227,45 +538,55 @@ /* Get the response */ if (!ret) { - ret = cros_ec_spi_receive_response(ec_dev, - ec_msg->in_len + EC_MSG_TX_PROTO_BYTES); + /* Verify that EC can process command */ + 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); } - /* turn off CS */ - spi_message_init(&msg); - final_ret = spi_sync(ec_spi->spi, &msg); - ktime_get_ts(&ts); - ec_spi->last_transfer_ns = timespec_to_ns(&ts); + final_ret = terminate_request(ec_dev); if (!ret) ret = final_ret; - if (ret < 0) { - dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret); - return ret; - } + if (ret < 0) + goto exit; - /* check response error code */ ptr = ec_dev->din; - if (ptr[0]) { - dev_warn(ec_dev->dev, "command 0x%02x returned an error %d\n", - ec_msg->cmd, ptr[0]); - debug_packet(ec_dev->dev, "in_err", ptr, len); - return -EINVAL; - } + + /* check response error code */ + 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->in_len) { + if (len > ec_msg->insize) { dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)", - len, ec_msg->in_len); - return -ENOSPC; + len, ec_msg->insize); + ret = -ENOSPC; + goto exit; } /* copy response packet payload and compute checksum */ for (i = 0; i < len; i++) { sum += ptr[i + 2]; - if (ec_msg->in_len) - ec_msg->in_buf[i] = ptr[i + 2]; + if (ec_msg->insize) + ec_msg->data[i] = ptr[i + 2]; } sum &= 0xff; @@ -275,13 +596,35 @@ dev_err(ec_dev->dev, "bad packet checksum, expected %02x, got %02x\n", sum, ptr[len + 2]); - return -EBADMSG; + ret = -EBADMSG; + goto exit; } - return 0; + 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_probe_spi(struct spi_device *spi) +static int cros_ec_spi_probe(struct spi_device *spi) { struct device *dev = &spi->dev; struct cros_ec_device *ec_dev; @@ -302,17 +645,21 @@ if (!ec_dev) return -ENOMEM; + /* Check for any DT properties */ + cros_ec_spi_dt_probe(ec_spi, dev); + spi_set_drvdata(spi, ec_dev); - ec_dev->name = "SPI"; ec_dev->dev = dev; ec_dev->priv = ec_spi; ec_dev->irq = spi->irq; - ec_dev->command_xfer = cros_ec_command_spi_xfer; - ec_dev->ec_name = ec_spi->spi->modalias; + 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->parent = &ec_spi->spi->dev; - ec_dev->din_size = EC_MSG_BYTES + EC_MSG_PREAMBLE_COUNT; - ec_dev->dout_size = EC_MSG_BYTES; + 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); + err = cros_ec_register(ec_dev); if (err) { @@ -320,10 +667,12 @@ return err; } + device_init_wakeup(&spi->dev, true); + return 0; } -static int cros_ec_remove_spi(struct spi_device *spi) +static int cros_ec_spi_remove(struct spi_device *spi) { struct cros_ec_device *ec_dev; @@ -352,6 +701,12 @@ 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", }, + { /* sentinel */ }, +}; +MODULE_DEVICE_TABLE(of, cros_ec_spi_of_match); + static const struct spi_device_id cros_ec_spi_id[] = { { "cros-ec-spi", 0 }, { } @@ -361,15 +716,15 @@ static struct spi_driver cros_ec_driver_spi = { .driver = { .name = "cros-ec-spi", - .owner = THIS_MODULE, + .of_match_table = of_match_ptr(cros_ec_spi_of_match), .pm = &cros_ec_spi_pm_ops, }, - .probe = cros_ec_probe_spi, - .remove = cros_ec_remove_spi, + .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"); +MODULE_LICENSE("GPL v2"); MODULE_DESCRIPTION("ChromeOS EC multi function device (SPI)");