Add EC host command support through rpmsg. Cc: Enric Balletbo Serra <eballe...@gmail.com> Cc: Guenter Roeck <gro...@chromium.org> Signed-off-by: Pi-Hsun Shih <pih...@chromium.org> --- Changes from v1: - Code format fix based on feedback for cros_ec_rpmsg.c. - Extract feature detection for SCP into separate patch (Patch 6). --- drivers/platform/chrome/Kconfig | 8 ++ drivers/platform/chrome/Makefile | 1 + drivers/platform/chrome/cros_ec_rpmsg.c | 159 ++++++++++++++++++++++++ 3 files changed, 168 insertions(+) create mode 100644 drivers/platform/chrome/cros_ec_rpmsg.c
diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig index 16b1615958aa2d..e3f63f3d67711b 100644 --- a/drivers/platform/chrome/Kconfig +++ b/drivers/platform/chrome/Kconfig @@ -72,6 +72,14 @@ config CROS_EC_SPI response time cannot be guaranteed, we support ignoring 'pre-amble' bytes before the response actually starts. +config CROS_EC_RPMSG + tristate "ChromeOS Embedded Controller (rpmsg)" + depends on MFD_CROS_EC && RPMSG && OF + help + If you say Y here, you get support for talking to the ChromeOS EC + through rpmsg. This uses a simple byte-level protocol with a + checksum. + config CROS_EC_LPC tristate "ChromeOS Embedded Controller (LPC)" depends on MFD_CROS_EC && ACPI && (X86 || COMPILE_TEST) diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile index cd591bf872bbe9..3e3190af2b50f4 100644 --- a/drivers/platform/chrome/Makefile +++ b/drivers/platform/chrome/Makefile @@ -8,6 +8,7 @@ cros_ec_ctl-objs := cros_ec_sysfs.o cros_ec_lightbar.o \ obj-$(CONFIG_CROS_EC_CTL) += cros_ec_ctl.o obj-$(CONFIG_CROS_EC_I2C) += cros_ec_i2c.o obj-$(CONFIG_CROS_EC_SPI) += cros_ec_spi.o +obj-$(CONFIG_CROS_EC_RPMSG) += cros_ec_rpmsg.o cros_ec_lpcs-objs := cros_ec_lpc.o cros_ec_lpc_reg.o cros_ec_lpcs-$(CONFIG_CROS_EC_LPC_MEC) += cros_ec_lpc_mec.o obj-$(CONFIG_CROS_EC_LPC) += cros_ec_lpcs.o diff --git a/drivers/platform/chrome/cros_ec_rpmsg.c b/drivers/platform/chrome/cros_ec_rpmsg.c new file mode 100644 index 00000000000000..92c967b4db4862 --- /dev/null +++ b/drivers/platform/chrome/cros_ec_rpmsg.c @@ -0,0 +1,159 @@ +// SPDX-License-Identifier: GPL-2.0 +// +// Copyright 2018 Google LLC. + +#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/rpmsg.h> +#include <linux/slab.h> + +/** + * cros_ec_cmd_xfer_rpmsg - Transfer a message over rpmsg and receive the reply + * + * This is only used for old EC proto version, and is not supported for this + * driver. + * + * @ec_dev: ChromeOS EC device + * @ec_msg: Message to transfer + */ +static int cros_ec_cmd_xfer_rpmsg(struct cros_ec_device *ec_dev, + struct cros_ec_command *ec_msg) +{ + return -EINVAL; +} + +/** + * cros_ec_pkt_xfer_rpmsg - Transfer a packet over rpmsg and receive the reply + * + * @ec_dev: ChromeOS EC device + * @ec_msg: Message to transfer + */ +static int cros_ec_pkt_xfer_rpmsg(struct cros_ec_device *ec_dev, + struct cros_ec_command *ec_msg) +{ + struct ec_host_response *response; + struct rpmsg_device *rpdev = ec_dev->priv; + int len; + u8 sum; + int ret; + int i; + + ec_msg->result = 0; + len = cros_ec_prepare_tx(ec_dev, ec_msg); + dev_dbg(ec_dev->dev, "prepared, len=%d\n", len); + + /* + * TODO: This currently relies on that mtk_rpmsg send actually blocks + * until ack. Should do the wait here instead. + */ + ret = rpmsg_send(rpdev->ept, ec_dev->dout, len); + if (ret) { + dev_err(ec_dev->dev, "rpmsg send failed\n"); + return ret; + } + + /* check response error code */ + response = (struct ec_host_response *)ec_dev->din; + ec_msg->result = response->result; + + ret = cros_ec_check_result(ec_dev, ec_msg); + if (ret) + goto exit; + + if (response->data_len > ec_msg->insize) { + dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)", + response->data_len, ec_msg->insize); + ret = -EMSGSIZE; + goto exit; + } + + /* copy response packet payload and compute checksum */ + memcpy(ec_msg->data, ec_dev->din + sizeof(*response), + response->data_len); + + sum = 0; + for (i = 0; i < sizeof(*response) + response->data_len; i++) + sum += ec_dev->din[i]; + + if (sum) { + dev_err(ec_dev->dev, "bad packet checksum, calculated %x\n", + sum); + ret = -EBADMSG; + goto exit; + } + + ret = response->data_len; +exit: + if (ec_msg->command == EC_CMD_REBOOT_EC) + msleep(EC_REBOOT_DELAY_MS); + + return ret; +} + +static int cros_ec_rpmsg_callback(struct rpmsg_device *rpdev, void *data, + int len, void *priv, u32 src) +{ + struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev); + + if (len > ec_dev->din_size) { + dev_warn(ec_dev->dev, + "ipi received length %d > din_size, truncating", len); + len = ec_dev->din_size; + } + + memcpy(ec_dev->din, data, len); + + return 0; +} + +static int cros_ec_rpmsg_probe(struct rpmsg_device *rpdev) +{ + struct device *dev = &rpdev->dev; + struct cros_ec_device *ec_dev; + int ret; + + ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL); + if (!ec_dev) + return -ENOMEM; + + ec_dev->dev = dev; + ec_dev->priv = rpdev; + ec_dev->cmd_xfer = cros_ec_cmd_xfer_rpmsg; + ec_dev->pkt_xfer = cros_ec_pkt_xfer_rpmsg; + ec_dev->phys_name = dev_name(&rpdev->dev); + ec_dev->din_size = sizeof(struct ec_host_response) + + sizeof(struct ec_response_get_protocol_info); + ec_dev->dout_size = sizeof(struct ec_host_request); + dev_set_drvdata(dev, ec_dev); + + ret = cros_ec_register(ec_dev); + if (ret) { + dev_err(dev, "cannot register EC\n"); + return ret; + } + + return 0; +} + +static const struct rpmsg_device_id cros_ec_rpmsg_device_id[] = { + { .name = "cros-ec-rpmsg", }, + { } +}; +MODULE_DEVICE_TABLE(rpmsg, cros_ec_rpmsg_device_id); + +static struct rpmsg_driver cros_ec_driver_rpmsg = { + .drv.name = KBUILD_MODNAME, + .id_table = cros_ec_rpmsg_device_id, + .probe = cros_ec_rpmsg_probe, + .callback = cros_ec_rpmsg_callback, +}; + +module_rpmsg_driver(cros_ec_driver_rpmsg); + +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("ChromeOS EC multi function device (rpmsg)"); -- 2.20.1.97.g81188d93c3-goog