cros: add cros_ec driver

This patch adds the cros_ec driver that implements the protocol for
communicating with Google's ChromeOS embedded controller.

Signed-off-by: Bernie Thompson <bhthompson@chromium.org>
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Signed-off-by: Che-Liang Chiou <clchiou@chromium.org>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Gabe Black <gabeblack@chromium.org>
Signed-off-by: Hung-ying Tyan <tyanh@chromium.org>
Signed-off-by: Louis Yung-Chieh Lo <yjlou@chromium.org>
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>

doc/device-tree-bindings/misc/cros-ec.txt

@@ -0,0 +1,38 @@
+Chrome OS CROS_EC Binding
+======================
+
+The device tree node which describes the operation of the CROS_EC interface
+is as follows:
+
+Required properties :
+- compatible = "google,cros-ec"
+
+Optional properties :
+- spi-max-frequency : Sets the maximum frequency (in Hz) for SPI bus
+   operation
+- i2c-max-frequency : Sets the maximum frequency (in Hz) for I2C bus
+   operation
+- ec-interrupt : Selects the EC interrupt, defined as a GPIO according
+   to the platform
+- optimise-flash-write : Boolean property - if present then flash blocks
+   containing all 0xff will not be written, since we assume that the EC
+   uses that pattern for erased blocks
+
+The CROS_EC node should appear as a subnode of the interrupt that connects it
+to the EC (e.g. i2c, spi, lpc). The reg property (as usual) will indicate
+the unit address on that bus.
+
+
+Example
+=======
+
+	spi@131b0000 {
+		cros-ec@0 {
+			reg = <0>;
+			compatible = "google,cros-ec";
+			spi-max-frequency = <5000000>;
+			ec-interrupt = <&gpio 174 1>;
+			optimise-flash-write;
+			status = "disabled";
+		};
+	};

drivers/misc/Makefile

@@ -28,6 +28,7 @@ LIB	:= $(obj)libmisc.o
 COBJS-$(CONFIG_ALI152X) += ali512x.o
 COBJS-$(CONFIG_DS4510)  += ds4510.o
 COBJS-$(CONFIG_CBMEM_CONSOLE) += cbmem_console.o
+COBJS-$(CONFIG_CROS_EC) += cros_ec.o
 COBJS-$(CONFIG_FSL_IIM) += fsl_iim.o
 COBJS-$(CONFIG_GPIO_LED) += gpio_led.o
 COBJS-$(CONFIG_FSL_MC9SDZ60) += mc9sdz60.o

include/cros_ec.h

@@ -0,0 +1,449 @@
+/*
+ * Chromium OS cros_ec driver
+ *
+ * Copyright (c) 2012 The Chromium OS Authors.
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#ifndef _CROS_EC_H
+#define _CROS_EC_H
+
+#include <linux/compiler.h>
+#include <ec_commands.h>
+#include <fdtdec.h>
+#include <cros_ec_message.h>
+
+/* Which interface is the device on? */
+enum cros_ec_interface_t {
+	CROS_EC_IF_NONE,
+	CROS_EC_IF_SPI,
+	CROS_EC_IF_I2C,
+	CROS_EC_IF_LPC,	/* Intel Low Pin Count interface */
+};
+
+/* Our configuration information */
+struct cros_ec_dev {
+	enum cros_ec_interface_t interface;
+	struct spi_slave *spi;		/* Our SPI slave, if using SPI */
+	int node;                       /* Our node */
+	int parent_node;		/* Our parent node (interface) */
+	unsigned int cs;		/* Our chip select */
+	unsigned int addr;		/* Device address (for I2C) */
+	unsigned int bus_num;		/* Bus number (for I2C) */
+	unsigned int max_frequency;	/* Maximum interface frequency */
+	struct fdt_gpio_state ec_int;	/* GPIO used as EC interrupt line */
+	int cmd_version_is_supported;   /* Device supports command versions */
+	int optimise_flash_write;	/* Don't write erased flash blocks */
+
+	/*
+	 * These two buffers will always be dword-aligned and include enough
+	 * space for up to 7 word-alignment bytes also, so we can ensure that
+	 * the body of the message is always dword-aligned (64-bit).
+	 *
+	 * We use this alignment to keep ARM and x86 happy. Probably word
+	 * alignment would be OK, there might be a small performance advantage
+	 * to using dword.
+	 */
+	uint8_t din[ALIGN(MSG_BYTES + sizeof(int64_t), sizeof(int64_t))]
+		__aligned(sizeof(int64_t));
+	uint8_t dout[ALIGN(MSG_BYTES + sizeof(int64_t), sizeof(int64_t))]
+		__aligned(sizeof(int64_t));
+};
+
+/*
+ * Hard-code the number of columns we happen to know we have right now.  It
+ * would be more correct to call cros_ec_info() at startup and determine the
+ * actual number of keyboard cols from there.
+ */
+#define CROS_EC_KEYSCAN_COLS 13
+
+/* Information returned by a key scan */
+struct mbkp_keyscan {
+	uint8_t data[CROS_EC_KEYSCAN_COLS];
+};
+
+/**
+ * Read the ID of the CROS-EC device
+ *
+ * The ID is a string identifying the CROS-EC device.
+ *
+ * @param dev		CROS-EC device
+ * @param id		Place to put the ID
+ * @param maxlen	Maximum length of the ID field
+ * @return 0 if ok, -1 on error
+ */
+int cros_ec_read_id(struct cros_ec_dev *dev, char *id, int maxlen);
+
+/**
+ * Read a keyboard scan from the CROS-EC device
+ *
+ * Send a message requesting a keyboard scan and return the result
+ *
+ * @param dev		CROS-EC device
+ * @param scan		Place to put the scan results
+ * @return 0 if ok, -1 on error
+ */
+int cros_ec_scan_keyboard(struct cros_ec_dev *dev, struct mbkp_keyscan *scan);
+
+/**
+ * Read which image is currently running on the CROS-EC device.
+ *
+ * @param dev		CROS-EC device
+ * @param image		Destination for image identifier
+ * @return 0 if ok, <0 on error
+ */
+int cros_ec_read_current_image(struct cros_ec_dev *dev,
+		enum ec_current_image *image);
+
+/**
+ * Read the hash of the CROS-EC device firmware.
+ *
+ * @param dev		CROS-EC device
+ * @param hash		Destination for hash information
+ * @return 0 if ok, <0 on error
+ */
+int cros_ec_read_hash(struct cros_ec_dev *dev,
+		struct ec_response_vboot_hash *hash);
+
+/**
+ * Send a reboot command to the CROS-EC device.
+ *
+ * Note that some reboot commands (such as EC_REBOOT_COLD) also reboot the AP.
+ *
+ * @param dev		CROS-EC device
+ * @param cmd		Reboot command
+ * @param flags         Flags for reboot command (EC_REBOOT_FLAG_*)
+ * @return 0 if ok, <0 on error
+ */
+int cros_ec_reboot(struct cros_ec_dev *dev, enum ec_reboot_cmd cmd,
+		uint8_t flags);
+
+/**
+ * Check if the CROS-EC device has an interrupt pending.
+ *
+ * Read the status of the external interrupt connected to the CROS-EC device.
+ * If no external interrupt is configured, this always returns 1.
+ *
+ * @param dev		CROS-EC device
+ * @return 0 if no interrupt is pending
+ */
+int cros_ec_interrupt_pending(struct cros_ec_dev *dev);
+
+enum {
+	CROS_EC_OK,
+	CROS_EC_ERR = 1,
+	CROS_EC_ERR_FDT_DECODE,
+	CROS_EC_ERR_CHECK_VERSION,
+	CROS_EC_ERR_READ_ID,
+	CROS_EC_ERR_DEV_INIT,
+};
+
+/**
+ * Set up the Chromium OS matrix keyboard protocol
+ *
+ * @param blob		Device tree blob containing setup information
+ * @param cros_ecp        Returns pointer to the cros_ec device, or NULL if none
+ * @return 0 if we got an cros_ec device and all is well (or no cros_ec is
+ *	expected), -ve if we should have an cros_ec device but failed to find
+ *	one, or init failed (-CROS_EC_ERR_...).
+ */
+int cros_ec_init(const void *blob, struct cros_ec_dev **cros_ecp);
+
+/**
+ * Read information about the keyboard matrix
+ *
+ * @param dev		CROS-EC device
+ * @param info		Place to put the info structure
+ */
+int cros_ec_info(struct cros_ec_dev *dev,
+		struct ec_response_cros_ec_info *info);
+
+/**
+ * Read the host event flags
+ *
+ * @param dev		CROS-EC device
+ * @param events_ptr	Destination for event flags.  Not changed on error.
+ * @return 0 if ok, <0 on error
+ */
+int cros_ec_get_host_events(struct cros_ec_dev *dev, uint32_t *events_ptr);
+
+/**
+ * Clear the specified host event flags
+ *
+ * @param dev		CROS-EC device
+ * @param events	Event flags to clear
+ * @return 0 if ok, <0 on error
+ */
+int cros_ec_clear_host_events(struct cros_ec_dev *dev, uint32_t events);
+
+/**
+ * Get/set flash protection
+ *
+ * @param dev		CROS-EC device
+ * @param set_mask	Mask of flags to set; if 0, just retrieves existing
+ *                      protection state without changing it.
+ * @param set_flags	New flag values; only bits in set_mask are applied;
+ *                      ignored if set_mask=0.
+ * @param prot          Destination for updated protection state from EC.
+ * @return 0 if ok, <0 on error
+ */
+int cros_ec_flash_protect(struct cros_ec_dev *dev,
+		       uint32_t set_mask, uint32_t set_flags,
+		       struct ec_response_flash_protect *resp);
+
+
+/**
+ * Run internal tests on the cros_ec interface.
+ *
+ * @param dev		CROS-EC device
+ * @return 0 if ok, <0 if the test failed
+ */
+int cros_ec_test(struct cros_ec_dev *dev);
+
+/**
+ * Update the EC RW copy.
+ *
+ * @param dev		CROS-EC device
+ * @param image		the content to write
+ * @param imafge_size	content length
+ * @return 0 if ok, <0 if the test failed
+ */
+int cros_ec_flash_update_rw(struct cros_ec_dev *dev,
+			 const uint8_t  *image, int image_size);
+
+/**
+ * Return a pointer to the board's CROS-EC device
+ *
+ * This should be implemented by board files.
+ *
+ * @return pointer to CROS-EC device, or NULL if none is available
+ */
+struct cros_ec_dev *board_get_cros_ec_dev(void);
+
+
+/* Internal interfaces */
+int cros_ec_i2c_init(struct cros_ec_dev *dev, const void *blob);
+int cros_ec_spi_init(struct cros_ec_dev *dev, const void *blob);
+int cros_ec_lpc_init(struct cros_ec_dev *dev, const void *blob);
+
+/**
+ * Read information from the fdt for the i2c cros_ec interface
+ *
+ * @param dev		CROS-EC device
+ * @param blob		Device tree blob
+ * @return 0 if ok, -1 if we failed to read all required information
+ */
+int cros_ec_i2c_decode_fdt(struct cros_ec_dev *dev, const void *blob);
+
+/**
+ * Read information from the fdt for the spi cros_ec interface
+ *
+ * @param dev		CROS-EC device
+ * @param blob		Device tree blob
+ * @return 0 if ok, -1 if we failed to read all required information
+ */
+int cros_ec_spi_decode_fdt(struct cros_ec_dev *dev, const void *blob);
+
+/**
+ * Check whether the LPC interface supports new-style commands.
+ *
+ * LPC has its own way of doing this, which involves checking LPC values
+ * visible to the host. Do this, and update dev->cmd_version_is_supported
+ * accordingly.
+ *
+ * @param dev		CROS-EC device to check
+ */
+int cros_ec_lpc_check_version(struct cros_ec_dev *dev);
+
+/**
+ * Send a command to an I2C CROS-EC device and return the reply.
+ *
+ * This rather complicated function deals with sending both old-style and
+ * new-style commands. The old ones have just a command byte and arguments.
+ * The new ones have version, command, arg-len, [args], chksum so are 3 bytes
+ * longer.
+ *
+ * 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
+ * @param din_len       Maximum size of response in bytes
+ * @return number of bytes in response, or -1 on error
+ */
+int cros_ec_i2c_command(struct cros_ec_dev *dev, uint8_t cmd, int cmd_version,
+		     const uint8_t *dout, int dout_len,
+		     uint8_t **dinp, int din_len);
+
+/**
+ * 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
+ * @param din_len       Maximum size of response in bytes
+ * @return number of bytes in response, or -1 on error
+ */
+int cros_ec_lpc_command(struct cros_ec_dev *dev, uint8_t cmd, int cmd_version,
+		     const uint8_t *dout, int dout_len,
+		     uint8_t **dinp, int din_len);
+
+int cros_ec_spi_command(struct cros_ec_dev *dev, uint8_t cmd, int cmd_version,
+		     const uint8_t *dout, int dout_len,
+		     uint8_t **dinp, int din_len);
+
+/**
+ * Dump a block of data for a command.
+ *
+ * @param name	Name for data (e.g. 'in', 'out')
+ * @param cmd	Command number associated with data, or -1 for none
+ * @param data	Data block to dump
+ * @param len	Length of data block to dump
+ */
+void cros_ec_dump_data(const char *name, int cmd, const uint8_t *data, int len);
+
+/**
+ * Calculate a simple 8-bit checksum of a data block
+ *
+ * @param data	Data block to checksum
+ * @param size	Size of data block in bytes
+ * @return checksum value (0 to 255)
+ */
+int cros_ec_calc_checksum(const uint8_t *data, int size);
+
+/**
+ * Decode a flash region parameter
+ *
+ * @param argc	Number of params remaining
+ * @param argv	List of remaining parameters
+ * @return flash region (EC_FLASH_REGION_...) or -1 on error
+ */
+int cros_ec_decode_region(int argc, char * const argv[]);
+
+int cros_ec_flash_erase(struct cros_ec_dev *dev, uint32_t offset,
+		uint32_t size);
+
+/**
+ * Read data from the flash
+ *
+ * Read an arbitrary amount of data from the EC flash, by repeatedly reading
+ * small blocks.
+ *
+ * The offset starts at 0. You can obtain the region information from
+ * cros_ec_flash_offset() to find out where to read for a particular region.
+ *
+ * @param dev		CROS-EC device
+ * @param data		Pointer to data buffer to read into
+ * @param offset	Offset within flash to read from
+ * @param size		Number of bytes to read
+ * @return 0 if ok, -1 on error
+ */
+int cros_ec_flash_read(struct cros_ec_dev *dev, uint8_t *data, uint32_t offset,
+		    uint32_t size);
+
+/**
+ * Write data to the flash
+ *
+ * Write an arbitrary amount of data to the EC flash, by repeatedly writing
+ * small blocks.
+ *
+ * The offset starts at 0. You can obtain the region information from
+ * cros_ec_flash_offset() to find out where to write for a particular region.
+ *
+ * Attempting to write to the region where the EC is currently running from
+ * will result in an error.
+ *
+ * @param dev		CROS-EC device
+ * @param data		Pointer to data buffer to write
+ * @param offset	Offset within flash to write to.
+ * @param size		Number of bytes to write
+ * @return 0 if ok, -1 on error
+ */
+int cros_ec_flash_write(struct cros_ec_dev *dev, const uint8_t *data,
+		     uint32_t offset, uint32_t size);
+
+/**
+ * Obtain position and size of a flash region
+ *
+ * @param dev		CROS-EC device
+ * @param region	Flash region to query
+ * @param offset	Returns offset of flash region in EC flash
+ * @param size		Returns size of flash region
+ * @return 0 if ok, -1 on error
+ */
+int cros_ec_flash_offset(struct cros_ec_dev *dev, enum ec_flash_region region,
+		      uint32_t *offset, uint32_t *size);
+
+/**
+ * Read/write VbNvContext from/to a CROS-EC device.
+ *
+ * @param dev		CROS-EC device
+ * @param block		Buffer of VbNvContext to be read/write
+ * @return 0 if ok, -1 on error
+ */
+int cros_ec_read_vbnvcontext(struct cros_ec_dev *dev, uint8_t *block);
+int cros_ec_write_vbnvcontext(struct cros_ec_dev *dev, const uint8_t *block);
+
+/**
+ * Read the version information for the EC images
+ *
+ * @param dev		CROS-EC device
+ * @param versionp	This is set to point to the version information
+ * @return 0 if ok, -1 on error
+ */
+int cros_ec_read_version(struct cros_ec_dev *dev,
+		       struct ec_response_get_version **versionp);
+
+/**
+ * Read the build information for the EC
+ *
+ * @param dev		CROS-EC device
+ * @param versionp	This is set to point to the build string
+ * @return 0 if ok, -1 on error
+ */
+int cros_ec_read_build_info(struct cros_ec_dev *dev, char **strp);
+
+/**
+ * Switch on/off a LDO / FET.
+ *
+ * @param dev		CROS-EC device
+ * @param index		index of the LDO/FET to switch
+ * @param state		new state of the LDO/FET : EC_LDO_STATE_ON|OFF
+ * @return 0 if ok, -1 on error
+ */
+int cros_ec_set_ldo(struct cros_ec_dev *dev, uint8_t index, uint8_t state);
+
+/**
+ * Read back a LDO / FET current state.
+ *
+ * @param dev		CROS-EC device
+ * @param index		index of the LDO/FET to switch
+ * @param state		current state of the LDO/FET : EC_LDO_STATE_ON|OFF
+ * @return 0 if ok, -1 on error
+ */
+int cros_ec_get_ldo(struct cros_ec_dev *dev, uint8_t index, uint8_t *state);
+#endif

include/cros_ec_message.h

@@ -0,0 +1,44 @@
+/*
+ * Chromium OS Matrix Keyboard Message Protocol definitions
+ *
+ * Copyright (c) 2012 The Chromium OS Authors.
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#ifndef _CROS_MESSAGE_H
+#define _CROS_MESSAGE_H
+
+/*
+ * Command interface between EC and AP, for LPC, I2C and SPI interfaces.
+ *
+ * This is copied from the Chromium OS Open Source Embedded Controller code.
+ */
+enum {
+	/* The header byte, which follows the preamble */
+	MSG_HEADER	= 0xec,
+
+	MSG_HEADER_BYTES	= 3,
+	MSG_TRAILER_BYTES	= 2,
+	MSG_PROTO_BYTES		= MSG_HEADER_BYTES + MSG_TRAILER_BYTES,
+
+	/* Max length of messages */
+	MSG_BYTES		= EC_HOST_PARAM_SIZE + MSG_PROTO_BYTES,
+};
+
+#endif

include/fdtdec.h

@@ -84,6 +84,7 @@ enum fdt_compat_id {
 	COMPAT_SAMSUNG_EXYNOS5_SOUND,	/* Exynos Sound */
 	COMPAT_WOLFSON_WM8994_CODEC,	/* Wolfson WM8994 Sound Codec */
 	COMPAT_SAMSUNG_EXYNOS_SPI,	/* Exynos SPI */
+	COMPAT_GOOGLE_CROS_EC,		/* Google CROS_EC Protocol */
 	COMPAT_SAMSUNG_EXYNOS_EHCI,	/* Exynos EHCI controller */
 	COMPAT_SAMSUNG_EXYNOS_USB_PHY,	/* Exynos phy controller for usb2.0 */
 	COMPAT_SAMSUNG_EXYNOS_TMU,	/* Exynos TMU */

lib/fdtdec.c

@@ -57,6 +57,7 @@ static const char * const compat_names[COMPAT_COUNT] = {
 	COMPAT(SAMSUNG_EXYNOS5_SOUND, "samsung,exynos-sound"),
 	COMPAT(WOLFSON_WM8994_CODEC, "wolfson,wm8994-codec"),
 	COMPAT(SAMSUNG_EXYNOS_SPI, "samsung,exynos-spi"),
+	COMPAT(GOOGLE_CROS_EC, "google,cros-ec"),
 	COMPAT(SAMSUNG_EXYNOS_EHCI, "samsung,exynos-ehci"),
 	COMPAT(SAMSUNG_EXYNOS_USB_PHY, "samsung,exynos-usb-phy"),
 	COMPAT(SAMSUNG_EXYNOS_TMU, "samsung,exynos-tmu"),