greybus: add an incoming request receive method

Define a new protocol method intended to handle the receipt of an
incoming operation request.  Most protocols have no expected
incoming requests and can leave this null.  If a request arrives for
a protocol with no request receive handler an error is reported and
the request fails.

Get rid of the previous fixed array of receive handlers, it's
no longer needed.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/staging/greybus/battery-gb.c

@@ -406,6 +406,7 @@ static struct gb_protocol battery_protocol = {
 	.minor			= 1,
 	.connection_init	= gb_battery_connection_init,
 	.connection_exit	= gb_battery_connection_exit,
+	.request_recv		= NULL,	/* no incoming requests */
 };
 
 bool gb_battery_protocol_init(void)

drivers/staging/greybus/gpio-gb.c

@@ -798,6 +798,7 @@ static struct gb_protocol gpio_protocol = {
 	.minor			= 1,
 	.connection_init	= gb_gpio_connection_init,
 	.connection_exit	= gb_gpio_connection_exit,
+	.request_recv		= NULL,	/* no incoming requests */
 };
 
 bool gb_gpio_protocol_init(void)

drivers/staging/greybus/i2c-gb.c

@@ -524,6 +524,7 @@ static struct gb_protocol i2c_protocol = {
 	.minor			= 1,
 	.connection_init	= gb_i2c_connection_init,
 	.connection_exit	= gb_i2c_connection_exit,
+	.request_recv		= NULL,	/* no incoming requests */
 };
 
 bool gb_i2c_protocol_init(void)

drivers/staging/greybus/operation.c

@@ -176,46 +176,25 @@ int gb_operation_wait(struct gb_operation *operation)
 
 }
 
-/*
- * This handler is used if no operation response messages are ever
- * expected for a given protocol.
- */
-static void gb_operation_recv_none(struct gb_operation *operation)
-{
-	/* Nothing to do! */
-}
-
-typedef void (*gb_operation_recv_handler)(struct gb_operation *operation);
-static gb_operation_recv_handler gb_operation_recv_handlers[] = {
-	[GREYBUS_PROTOCOL_CONTROL]	= NULL,
-	[GREYBUS_PROTOCOL_AP]		= NULL,
-	[GREYBUS_PROTOCOL_GPIO]		= NULL,
-	[GREYBUS_PROTOCOL_I2C]		= gb_operation_recv_none,
-	[GREYBUS_PROTOCOL_UART]		= NULL,
-	[GREYBUS_PROTOCOL_HID]		= NULL,
-	[GREYBUS_PROTOCOL_BATTERY]	= gb_operation_recv_none,
-	[GREYBUS_PROTOCOL_LED]		= NULL,
-	[GREYBUS_PROTOCOL_VENDOR]	= NULL,
-};
-
 static void gb_operation_request_handle(struct gb_operation *operation)
 {
-	u8 protocol_id = operation->connection->protocol->id;
-
-	/* Subtract one from array size to stay within u8 range */
-	if (protocol_id <= (u8)(ARRAY_SIZE(gb_operation_recv_handlers) - 1)) {
-		gb_operation_recv_handler handler;
+	struct gb_protocol *protocol = operation->connection->protocol;
+	struct gb_operation_msg_hdr *header;
 
-		handler = gb_operation_recv_handlers[protocol_id];
-		if (handler) {
-			handler(operation);	/* Handle the request */
-			return;
-		}
+	/*
+	 * If the protocol has no incoming request handler, report
+	 * an error and mark the request bad.
+	 */
+	if (protocol->request_recv) {
+		protocol->request_recv(operation);
+		goto out;
 	}
 
+	header = operation->request->transfer_buffer;
 	gb_connection_err(operation->connection,
-		"unrecognized protocol id %hhu\n", protocol_id);
+		"unexpected incoming request type 0x%02hhx\n", header->type);
 	operation->result = GB_OP_PROTOCOL_BAD;
+out:
 	gb_operation_complete(operation);
 }
 

drivers/staging/greybus/protocol.h

@@ -11,8 +11,11 @@
 
 #include "greybus.h"
 
+struct gb_operation;
+
 typedef int (*gb_connection_init_t)(struct gb_connection *);
 typedef void (*gb_connection_exit_t)(struct gb_connection *);
+typedef void (*gb_request_recv_t)(struct gb_operation *);
 
 /*
  * Protocols having the same id but different major and/or minor
@@ -29,6 +32,7 @@ struct gb_protocol {
 
 	gb_connection_init_t	connection_init;
 	gb_connection_exit_t	connection_exit;
+	gb_request_recv_t	request_recv;
 };
 
 bool gb_protocol_register(struct gb_protocol *protocol);

drivers/staging/greybus/sdio-gb.c

@@ -83,6 +83,7 @@ static struct gb_protocol sdio_protocol = {
 	.minor			= 1,
 	.connection_init	= gb_sdio_connection_init,
 	.connection_exit	= gb_sdio_connection_exit,
+	.request_recv		= NULL,	/* no incoming requests */
 };
 
 bool gb_sdio_protocol_init(void)

drivers/staging/greybus/uart-gb.c

@@ -526,6 +526,7 @@ static struct gb_protocol uart_protocol = {
 	.minor			= 1,
 	.connection_init	= gb_uart_connection_init,
 	.connection_exit	= gb_uart_connection_exit,
+	.request_recv		= NULL,	/* no incoming requests */
 };
 
 bool gb_uart_protocol_init(void)