Pass maximum size of response buffer in via host command handler args

BUG=chrome-os-partner:11275
TEST=from u-boot prompt, 'mkbp hash'

Change-Id: I4cf37acfdd8e4edfe2cb6259b0fc6d0860ef0f79
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/27225

7 files changed, 12 insertions, 6 deletions

diff --git a/chip/lm4/lpc.c b/chip/lm4/lpc.c
index 73f55bbb9d..eb66289615 100644
--- a/chip/lm4/lpc.c
+++ b/chip/lm4/lpc.c
@@ -377,6 +377,7 @@ static void lpc_interrupt(void)
 		host_cmd_args.params = host_get_buffer();
 		host_cmd_args.params_size = EC_PARAM_SIZE;
 		host_cmd_args.response = host_get_buffer();
+		host_cmd_args.response_max = EC_PARAM_SIZE;
 		host_cmd_args.response_size = 0;
 		host_command_received(&host_cmd_args);
 	}
diff --git a/chip/stm32/i2c.c b/chip/stm32/i2c.c
index 51ed3ae1dd..bb6fb729a9 100644
--- a/chip/stm32/i2c.c
+++ b/chip/stm32/i2c.c
@@ -179,6 +179,7 @@ static void i2c_event_handler(int port)
 				host_cmd_args.params_size = EC_PARAM_SIZE;
 				/* skip room for error code */
 				host_cmd_args.response = host_buffer + 1;
+				host_cmd_args.response_max = EC_PARAM_SIZE;
 				host_cmd_args.response_size = 0;
 				host_command_received(&host_cmd_args);
 				/* reset host buffer after end of transfer */
diff --git a/chip/stm32/spi.c b/chip/stm32/spi.c
index 43386cbe0a..219b82311a 100644
--- a/chip/stm32/spi.c
+++ b/chip/stm32/spi.c
@@ -192,6 +192,7 @@ static void spi_interrupt(int port)
 	args.params_size = sizeof(out_msg) - SPI_MSG_PROTO_BYTES;
 	/* TODO: use a different initial buffer for params vs. response */
 	args.response = args.params;
+	args.response_max = sizeof(out_msg) - SPI_MSG_PROTO_BYTES;
 	args.response_size = 0;
 
 	status = host_command_process(&args);
diff --git a/common/flash_commands.c b/common/flash_commands.c
index d8953bc3c7..590e090b0e 100644
--- a/common/flash_commands.c
+++ b/common/flash_commands.c
@@ -207,9 +207,6 @@ static int flash_command_read(struct host_cmd_handler_args *args)
 	const struct ec_params_flash_read *p =
 		(const struct ec_params_flash_read *)args->params;
 
-	if (p->size > EC_PARAM_SIZE)
-		return EC_RES_INVALID_PARAM;
-
 	if (flash_dataptr(p->offset, p->size, 1, (char **)&args->response) < 0)
 		return EC_RES_ERROR;
 
diff --git a/common/host_command.c b/common/host_command.c
index 716119b909..3e0ea06d5d 100644
--- a/common/host_command.c
+++ b/common/host_command.c
@@ -146,7 +146,7 @@ static int host_command_read_memmap(struct host_cmd_handler_args *args)
 	uint8_t offset = p->offset;
 	uint8_t size = p->size;
 
-	if (size > EC_PARAM_SIZE || offset > EC_MEMMAP_SIZE ||
+	if (size > EC_MEMMAP_SIZE || offset > EC_MEMMAP_SIZE ||
 	    offset + size > EC_MEMMAP_SIZE)
 		return EC_RES_INVALID_PARAM;
 
diff --git a/common/pstore_commands.c b/common/pstore_commands.c
index 9717d3ccdb..4b09c9bfcd 100644
--- a/common/pstore_commands.c
+++ b/common/pstore_commands.c
@@ -37,7 +37,7 @@ int pstore_command_read(struct host_cmd_handler_args *args)
 	int offset = p->offset % block_size;
 	int bytes_left = p->size;
 
-	if (p->size > sizeof(EC_PARAM_SIZE))
+	if (p->size > args->response_max)
 		return EC_RES_INVALID_PARAM;
 
 	while (bytes_left) {
diff --git a/include/host_command.h b/include/host_command.h
index 566d90f190..fa2a52119d 100644
--- a/include/host_command.h
+++ b/include/host_command.h
@@ -19,11 +19,17 @@ struct host_cmd_handler_args {
 	uint8_t params_size;   /* Size of input parameters in bytes */
 	/*
 	 * Pointer to output response data buffer.  On input to the handler,
-	 * points to a EC_PARAM_SIZE-byte buffer.  Command handler can change
+	 * points to a buffer of size response_max.  Command handler can change
 	 * this to point to a different location instead of memcpy()'ing data
 	 * into the provided buffer.
 	 */
 	uint8_t *response;
+	/*
+	 * Maximum size of response buffer provided to command handler.  If the
+	 * handler changes response to point to its own larger buffer, it may
+	 * return a response_size greater than response_max.
+	 */
+	uint8_t response_max;
 	uint8_t response_size; /* Size of data pointed to by resp_ptr */
 };