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drivers/misc/cros_ec_spi.c
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d41ce506b Initial Release, ... |
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/* * Chromium OS cros_ec driver - SPI interface * * Copyright (c) 2012 The Chromium OS Authors. * * SPDX-License-Identifier: GPL-2.0+ */ /* * The Matrix Keyboard Protocol driver handles talking to the keyboard * controller chip. Mostly this is for keyboard functions, but some other * things have slipped in, so we provide generic services to talk to the * KBC. */ #include <common.h> #include <cros_ec.h> #include <dm.h> #include <errno.h> #include <spi.h> DECLARE_GLOBAL_DATA_PTR; int cros_ec_spi_packet(struct udevice *udev, int out_bytes, int in_bytes) { struct cros_ec_dev *dev = dev_get_uclass_priv(udev); struct spi_slave *slave = dev_get_parent_priv(dev->dev); ulong start; uint8_t byte; int rv; /* Do the transfer */ if (spi_claim_bus(slave)) { debug("%s: Cannot claim SPI bus ", __func__); return -1; } rv = spi_xfer(slave, out_bytes * 8, dev->dout, NULL, SPI_XFER_BEGIN); if (rv) goto done; start = get_timer(0); while (1) { rv = spi_xfer(slave, 8, NULL, &byte, 0); if (byte == SPI_PREAMBLE_END_BYTE) break; if (rv) goto done; if (get_timer(start) > 100) { rv = -ETIMEDOUT; goto done; } } rv = spi_xfer(slave, in_bytes * 8, NULL, dev->din, 0); done: spi_xfer(slave, 0, NULL, NULL, SPI_XFER_END); spi_release_bus(slave); if (rv) { debug("%s: Cannot complete SPI transfer ", __func__); return -1; } return in_bytes; } /** * Send a command to a LPC CROS_EC device and return the reply. * * The device's internal input/output buffers are used. * * @param dev CROS_EC device * @param cmd Command to send (EC_CMD_...) * @param cmd_version Version of command to send (EC_VER_...) * @param dout Output data (may be NULL If dout_len=0) * @param dout_len Size of output data in bytes * @param dinp Returns pointer to response data. This will be * untouched unless we return a value > 0. * @param din_len Maximum size of response in bytes * @return number of bytes in response, or -1 on error */ int cros_ec_spi_command(struct udevice *udev, uint8_t cmd, int cmd_version, const uint8_t *dout, int dout_len, uint8_t **dinp, int din_len) { struct cros_ec_dev *dev = dev_get_uclass_priv(udev); struct spi_slave *slave = dev_get_parent_priv(dev->dev); int in_bytes = din_len + 4; /* status, length, checksum, trailer */ uint8_t *out; uint8_t *p; int csum, len; int rv; if (dev->protocol_version != 2) { debug("%s: Unsupported EC protcol version %d ", __func__, dev->protocol_version); return -1; } /* * Sanity-check input size to make sure it plus transaction overhead * fits in the internal device buffer. */ if (in_bytes > sizeof(dev->din)) { debug("%s: Cannot receive %d bytes ", __func__, din_len); return -1; } /* We represent message length as a byte */ if (dout_len > 0xff) { debug("%s: Cannot send %d bytes ", __func__, dout_len); return -1; } /* * Clear input buffer so we don't get false hits for MSG_HEADER */ memset(dev->din, '\0', in_bytes); if (spi_claim_bus(slave)) { debug("%s: Cannot claim SPI bus ", __func__); return -1; } out = dev->dout; out[0] = EC_CMD_VERSION0 + cmd_version; out[1] = cmd; out[2] = (uint8_t)dout_len; memcpy(out + 3, dout, dout_len); csum = cros_ec_calc_checksum(out, 3) + cros_ec_calc_checksum(dout, dout_len); out[3 + dout_len] = (uint8_t)csum; /* * Send output data and receive input data starting such that the * message body will be dword aligned. */ p = dev->din + sizeof(int64_t) - 2; len = dout_len + 4; cros_ec_dump_data("out", cmd, out, len); rv = spi_xfer(slave, max(len, in_bytes) * 8, out, p, SPI_XFER_BEGIN | SPI_XFER_END); spi_release_bus(slave); if (rv) { debug("%s: Cannot complete SPI transfer ", __func__); return -1; } len = min((int)p[1], din_len); cros_ec_dump_data("in", -1, p, len + 3); /* Response code is first byte of message */ if (p[0] != EC_RES_SUCCESS) { printf("%s: Returned status %d ", __func__, p[0]); return -(int)(p[0]); } /* Check checksum */ csum = cros_ec_calc_checksum(p, len + 2); if (csum != p[len + 2]) { debug("%s: Invalid checksum rx %#02x, calced %#02x ", __func__, p[2 + len], csum); return -1; } /* Anything else is the response data */ *dinp = p + 2; return len; } static int cros_ec_probe(struct udevice *dev) { return cros_ec_register(dev); } static struct dm_cros_ec_ops cros_ec_ops = { .packet = cros_ec_spi_packet, .command = cros_ec_spi_command, }; static const struct udevice_id cros_ec_ids[] = { { .compatible = "google,cros-ec-spi" }, { } }; U_BOOT_DRIVER(cros_ec_spi) = { .name = "cros_ec_spi", .id = UCLASS_CROS_EC, .of_match = cros_ec_ids, .probe = cros_ec_probe, .ops = &cros_ec_ops, }; |