greybus: Add firmware protocol driver

This adds firmware protocol driver based on the latest specs available
on mailing lists. This uses the firmware framework present in kernel.

Refer Documentation/firmware_class/README on how it works.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/Makefile

@@ -10,6 +10,7 @@ greybus-y :=	core.o		\
 		protocol.o	\
 		control.o	\
 		svc.o		\
+		firmware.o	\
 		operation.o
 
 gb-phy-y :=	gpbridge.o	\

drivers/staging/greybus/core.c

@@ -300,8 +300,16 @@ static int __init gb_init(void)
 		goto error_svc;
 	}
 
+	retval = gb_firmware_protocol_init();
+	if (retval) {
+		pr_err("gb_firmware_protocol_init failed\n");
+		goto error_firmware;
+	}
+
 	return 0;	/* Success */
 
+error_firmware:
+	gb_svc_protocol_exit();
 error_svc:
 	gb_control_protocol_exit();
 error_control:
@@ -321,6 +329,7 @@ module_init(gb_init);
 
 static void __exit gb_exit(void)
 {
+	gb_firmware_protocol_exit();
 	gb_svc_protocol_exit();
 	gb_control_protocol_exit();
 	gb_endo_exit();

drivers/staging/greybus/firmware.c

+/*
+ * FIRMWARE Greybus driver.
+ *
+ * Copyright 2015 Google Inc.
+ * Copyright 2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/firmware.h>
+
+#include "greybus.h"
+
+struct gb_firmware {
+	struct gb_connection	*connection;
+	const struct firmware	*fw;
+};
+
+static void free_firmware(struct gb_firmware *firmware)
+{
+	release_firmware(firmware->fw);
+	firmware->fw = NULL;
+}
+
+/* This returns path of the firmware blob on the disk */
+static int download_firmware(struct gb_firmware *firmware, u8 stage)
+{
+	struct gb_connection *connection = firmware->connection;
+	struct gb_interface *intf = connection->bundle->intf;
+	char firmware_name[28];
+
+	/* Already have a firmware, free it */
+	if (firmware->fw)
+		free_firmware(firmware);
+
+	/*
+	 * Create firmware name
+	 *
+	 * XXX Name it properly..
+	 */
+	sprintf(firmware_name, "ara:%04x:%04x:%04x:%04x:%04x.fw", intf->unipro_mfg_id,
+		intf->unipro_prod_id, intf->ara_vend_id, intf->ara_prod_id,
+		stage);
+
+	return request_firmware(&firmware->fw, firmware_name, &connection->dev);
+}
+
+static int gb_firmware_size_request(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct gb_firmware *firmware = connection->private;
+	struct gb_firmware_size_request *size_request = op->request->payload;
+	struct gb_firmware_size_response *size_response;
+	struct device *dev = &connection->dev;
+	int ret;
+
+	if (op->request->payload_size != sizeof(*size_request)) {
+		dev_err(dev, "%s: illegal size of firmware size request (%zu != %zu)\n",
+			__func__, op->request->payload_size,
+			sizeof(*size_request));
+		return -EINVAL;
+	}
+
+	ret = download_firmware(firmware, size_request->stage);
+	if (ret) {
+		dev_err(dev, "%s: failed to download firmware (%d)\n", __func__,
+			ret);
+		return ret;
+	}
+
+	if (!gb_operation_response_alloc(op, sizeof(*size_response),
+					 GFP_KERNEL)) {
+		dev_err(dev, "%s: error allocating response\n", __func__);
+		free_firmware(firmware);
+		return -ENOMEM;
+	}
+
+	size_response = op->response->payload;
+	size_response->size = cpu_to_le32(firmware->fw->size);
+
+	return 0;
+}
+
+static int gb_firmware_get_firmware(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct gb_firmware *firmware = connection->private;
+	struct gb_firmware_get_firmware_request *firmware_request = op->request->payload;
+	struct gb_firmware_get_firmware_response *firmware_response;
+	struct device *dev = &connection->dev;
+	unsigned int offset, size;
+
+	if (op->request->payload_size != sizeof(*firmware_request)) {
+		dev_err(dev, "%s: Illegal size of get firmware request (%zu %zu)\n",
+			__func__, op->request->payload_size,
+			sizeof(*firmware_request));
+		return -EINVAL;
+	}
+
+	if (!firmware->fw) {
+		dev_err(dev, "%s: firmware not available\n", __func__);
+		return -EINVAL;
+	}
+
+	offset = le32_to_cpu(firmware_request->offset);
+	size = le32_to_cpu(firmware_request->size);
+
+	if (!gb_operation_response_alloc(op, sizeof(*firmware_response) + size,
+					 GFP_KERNEL)) {
+		dev_err(dev, "%s: error allocating response\n", __func__);
+		return -ENOMEM;
+	}
+
+	firmware_response = op->response->payload;
+	memcpy(firmware_response->data, firmware->fw->data + offset, size);
+
+	return 0;
+}
+
+static int gb_firmware_ready_to_boot(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct gb_firmware_ready_to_boot_request *rtb_request = op->request->payload;
+	struct device *dev = &connection->dev;
+	u8 stage, status;
+
+	if (op->request->payload_size != sizeof(*rtb_request)) {
+		dev_err(dev, "%s: Illegal size of ready to boot request (%zu %zu)\n",
+			__func__, op->request->payload_size,
+			sizeof(*rtb_request));
+		return -EINVAL;
+	}
+
+	stage = rtb_request->stage;
+	status = rtb_request->status;
+
+	/* Return error if the blob was invalid */
+	if (status == GB_FIRMWARE_BOOT_STATUS_INVALID)
+		return -EINVAL;
+
+	/*
+	 * XXX Should we return error for insecure firmware?
+	 */
+
+	return 0;
+}
+
+static int gb_firmware_request_recv(u8 type, struct gb_operation *op)
+{
+	switch (type) {
+	case GB_FIRMWARE_TYPE_FIRMWARE_SIZE:
+		return gb_firmware_size_request(op);
+	case GB_FIRMWARE_TYPE_GET_FIRMWARE:
+		return gb_firmware_get_firmware(op);
+	case GB_FIRMWARE_TYPE_READY_TO_BOOT:
+		return gb_firmware_ready_to_boot(op);
+	default:
+		dev_err(&op->connection->dev,
+			"unsupported request: %hhu\n", type);
+		return -EINVAL;
+	}
+}
+
+static int gb_firmware_connection_init(struct gb_connection *connection)
+{
+	struct gb_firmware *firmware;
+
+	firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
+	if (!firmware)
+		return -ENOMEM;
+
+	firmware->connection = connection;
+	connection->private = firmware;
+
+	return 0;
+}
+
+static void gb_firmware_connection_exit(struct gb_connection *connection)
+{
+	struct gb_firmware *firmware = connection->private;
+
+	/* Release firmware */
+	if (firmware->fw)
+		free_firmware(firmware);
+
+	connection->private = NULL;
+	kfree(firmware);
+}
+
+static struct gb_protocol firmware_protocol = {
+	.name			= "firmware",
+	.id			= GREYBUS_PROTOCOL_FIRMWARE,
+	.major			= GB_FIRMWARE_VERSION_MAJOR,
+	.minor			= GB_FIRMWARE_VERSION_MINOR,
+	.connection_init	= gb_firmware_connection_init,
+	.connection_exit	= gb_firmware_connection_exit,
+	.request_recv		= gb_firmware_request_recv,
+};
+gb_builtin_protocol_driver(firmware_protocol);

drivers/staging/greybus/firmware.h

+/*
+ * Greybus firmware code
+ *
+ * Copyright 2015 Google Inc.
+ * Copyright 2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#ifndef __FIRMWARE_H
+#define __FIRMWARE_H
+
+int gb_firmware_protocol_init(void);
+void gb_firmware_protocol_exit(void);
+
+#endif /* __FIRMWARE_H */

drivers/staging/greybus/greybus.h

@@ -27,6 +27,7 @@
 #include "manifest.h"
 #include "endo.h"
 #include "svc.h"
+#include "firmware.h"
 #include "module.h"
 #include "control.h"
 #include "interface.h"

drivers/staging/greybus/greybus_manifest.h

@@ -43,6 +43,7 @@ enum greybus_protocol {
 	GREYBUS_PROTOCOL_I2S_RECEIVER	= 0x12,
 	GREYBUS_PROTOCOL_I2S_TRANSMITTER = 0x13,
 	GREYBUS_PROTOCOL_SVC            = 0x14,
+	GREYBUS_PROTOCOL_FIRMWARE	= 0x15,
 		/* ... */
 	GREYBUS_PROTOCOL_RAW		= 0xfe,
 	GREYBUS_PROTOCOL_VENDOR		= 0xff,
@@ -70,6 +71,7 @@ enum greybus_class_type {
 	GREYBUS_CLASS_I2S_RECEIVER	= 0x12,
 	GREYBUS_CLASS_I2S_TRANSMITTER	= 0x13,
 	GREYBUS_CLASS_SVC		= 0x14,
+	GREYBUS_CLASS_FIRMWARE		= 0x15,
 		/* ... */
 	GREYBUS_CLASS_RAW		= 0xfe,
 	GREYBUS_CLASS_VENDOR		= 0xff,

drivers/staging/greybus/greybus_protocols.h

@@ -146,6 +146,60 @@ struct gb_control_disconnected_request {
 };
 /* Control protocol [dis]connected response has no payload */
 
+
+/* Firmware Protocol */
+
+/* Version of the Greybus firmware protocol we support */
+#define GB_FIRMWARE_VERSION_MAJOR		0x00
+#define GB_FIRMWARE_VERSION_MINOR		0x01
+
+/* Greybus firmware request types */
+#define GB_FIRMWARE_TYPE_INVALID		0x00
+#define GB_FIRMWARE_TYPE_PROTOCOL_VERSION	0x01
+#define GB_FIRMWARE_TYPE_FIRMWARE_SIZE		0x02
+#define GB_FIRMWARE_TYPE_GET_FIRMWARE		0x03
+#define GB_FIRMWARE_TYPE_READY_TO_BOOT		0x04
+
+/* Greybus firmware boot stages */
+#define GB_FIRMWARE_BOOT_STAGE_ONE		0x01 /* Reserved for the boot ROM */
+#define GB_FIRMWARE_BOOT_STAGE_TWO		0x02 /* Firmware package to be loaded by the boot ROM */
+#define GB_FIRMWARE_BOOT_STAGE_THREE		0x03 /* Module personality package loaded by Stage 2 firmware */
+
+/* Greybus firmware ready to boot status */
+#define GB_FIRMWARE_BOOT_STATUS_INVALID		0x00 /* Firmware blob could not be validated */
+#define GB_FIRMWARE_BOOT_STATUS_INSECURE	0x01 /* Firmware blob is valid but insecure */
+#define GB_FIRMWARE_BOOT_STATUS_SECURE		0x02 /* Firmware blob is valid and secure */
+
+/* Max firmware data fetch size in bytes */
+#define GB_FIRMWARE_FETCH_MAX			2000
+
+/* Firmware protocol firmware size request/response */
+struct gb_firmware_size_request {
+	__u8			stage;
+};
+
+struct gb_firmware_size_response {
+	__le32			size;
+};
+
+/* Firmware protocol get firmware request/response */
+struct gb_firmware_get_firmware_request {
+	__le32			offset;
+	__le32			size;
+};
+
+struct gb_firmware_get_firmware_response {
+	__u8			data[0];
+};
+
+/* Firmware protocol Ready to boot request */
+struct gb_firmware_ready_to_boot_request {
+	__u8			stage;
+	__u8			status;
+};
+/* Firmware protocol Ready to boot response has no payload */
+
+
 /* I2C */
 
 /* Version of the Greybus i2c protocol we support */