chips/stm32/usb_spi: Forwarding to multiple spi devices

For devices similar to Servo Micro, in case of multiple entries in
spi_devices, this change allows the USB host to request which device its
transaction requests are to be forwarded to.

BUG=b:192262089
TEST=HyperDebug board forwards to two SPI busses

Change-Id: Ic94e66a8d7f5502c3016a26a1beb24236b3c4893
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/4077428
Commit-Queue: Jes Klinke <jbk@chromium.org>
Tested-by: Jes Klinke <jbk@chromium.org>
Code-Coverage: Zoss <zoss-cl-coverage@prod.google.com>
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>

8 files changed, 43 insertions, 13 deletions

diff --git a/board/c2d2/board.c b/board/c2d2/board.c
index 9c131e17d5..02fce6143e 100644
--- a/board/c2d2/board.c
+++ b/board/c2d2/board.c
@@ -293,7 +293,7 @@ USB_STREAM_CONFIG_USART_IFACE(usart4_usb, USB_IFACE_USART4_STREAM,
 
 /* SPI devices */
 const struct spi_device_t spi_devices[] = {
-	{ CONFIG_SPI_FLASH_PORT, 1, GPIO_SPI_CSN },
+	{ CONFIG_SPI_FLASH_PORT, 1, GPIO_SPI_CSN, USB_SPI_ENABLED },
 };
 const unsigned int spi_devices_used = ARRAY_SIZE(spi_devices);
 
diff --git a/board/discovery-stm32f072/board.c b/board/discovery-stm32f072/board.c
index 6d8d9820ac..fb61ea1232 100644
--- a/board/discovery-stm32f072/board.c
+++ b/board/discovery-stm32f072/board.c
@@ -128,7 +128,7 @@ BUILD_ASSERT(ARRAY_SIZE(usb_strings) == USB_STR_COUNT);
 
 /* SPI devices */
 const struct spi_device_t spi_devices[] = {
-	{ CONFIG_SPI_FLASH_PORT, 0, GPIO_SPI_CS },
+	{ CONFIG_SPI_FLASH_PORT, 0, GPIO_SPI_CS, USB_SPI_ENABLED },
 };
 const unsigned int spi_devices_used = ARRAY_SIZE(spi_devices);
 
diff --git a/board/hammer/board.c b/board/hammer/board.c
index 496555149d..85be6a0449 100644
--- a/board/hammer/board.c
+++ b/board/hammer/board.c
@@ -79,7 +79,8 @@ BUILD_ASSERT(ARRAY_SIZE(usb_strings) == USB_STR_COUNT);
 #ifdef HAS_SPI_TOUCHPAD
 /* SPI devices */
 const struct spi_device_t spi_devices[] = {
-	[SPI_ST_TP_DEVICE_ID] = { CONFIG_SPI_TOUCHPAD_PORT, 2, GPIO_SPI1_NSS },
+	[SPI_ST_TP_DEVICE_ID] = { CONFIG_SPI_TOUCHPAD_PORT, 2, GPIO_SPI1_NSS,
+				  USB_SPI_ENABLED },
 };
 const unsigned int spi_devices_used = ARRAY_SIZE(spi_devices);
 
diff --git a/board/hyperdebug/board.c b/board/hyperdebug/board.c
index b98cbc8d4c..63ce786e47 100644
--- a/board/hyperdebug/board.c
+++ b/board/hyperdebug/board.c
@@ -128,7 +128,7 @@ USB_STREAM_CONFIG(usart5_usb, USB_IFACE_USART5_STREAM,
 
 /* SPI devices */
 const struct spi_device_t spi_devices[] = {
-	{ 1 /* SPI2 */, 7, GPIO_SPI2_CS },
+	{ 1 /* SPI2 */, 7, GPIO_SPI2_CS, USB_SPI_ENABLED },
 };
 const unsigned int spi_devices_used = ARRAY_SIZE(spi_devices);
 
diff --git a/board/servo_micro/board.c b/board/servo_micro/board.c
index 5f0786cf45..9fbc4be635 100644
--- a/board/servo_micro/board.c
+++ b/board/servo_micro/board.c
@@ -298,7 +298,7 @@ BUILD_ASSERT(ARRAY_SIZE(usb_strings) == USB_STR_COUNT);
 
 /* SPI devices */
 const struct spi_device_t spi_devices[] = {
-	{ CONFIG_SPI_FLASH_PORT, 1, GPIO_SPI_CS },
+	{ CONFIG_SPI_FLASH_PORT, 1, GPIO_SPI_CS, USB_SPI_ENABLED },
 };
 const unsigned int spi_devices_used = ARRAY_SIZE(spi_devices);
 
diff --git a/chip/stm32/usb_spi.c b/chip/stm32/usb_spi.c
index 5ea813a86c..35bd07d103 100644
--- a/chip/stm32/usb_spi.c
+++ b/chip/stm32/usb_spi.c
@@ -346,13 +346,15 @@ static void usb_spi_process_rx_packet(struct usb_spi_config const *config,
 		 * asserted or deasserted.
 		 */
 		uint16_t flags = packet->cmd_cs.flags;
+		const struct spi_device_t *current_device =
+			&spi_devices[config->state->current_spi_device_idx];
 
 		if (flags & USB_SPI_CHIP_SELECT) {
 			/* Set chip select low (asserted). */
-			gpio_set_level(SPI_FLASH_DEVICE->gpio_cs, 0);
+			gpio_set_level(current_device->gpio_cs, 0);
 		} else {
 			/* Set chip select high (adesserted). */
-			gpio_set_level(SPI_FLASH_DEVICE->gpio_cs, 1);
+			gpio_set_level(current_device->gpio_cs, 1);
 		}
 		config->state->mode = USB_SPI_MODE_SEND_CHIP_SELECT_RESPONSE;
 		break;
@@ -422,6 +424,8 @@ void usb_spi_deferred(struct usb_spi_config const *config)
 
 	/* Start a new SPI transfer. */
 	if (config->state->mode == USB_SPI_MODE_START_SPI) {
+		const struct spi_device_t *current_device =
+			&spi_devices[config->state->current_spi_device_idx];
 		uint16_t status_code;
 		int read_count = config->state->spi_read_ctx.transfer_size;
 #ifndef CONFIG_SPI_HALFDUPLEX
@@ -436,7 +440,7 @@ void usb_spi_deferred(struct usb_spi_config const *config)
 		}
 #endif
 		status_code = spi_transaction(
-			SPI_FLASH_DEVICE, config->state->spi_write_ctx.buffer,
+			current_device, config->state->spi_write_ctx.buffer,
 			config->state->spi_write_ctx.transfer_size,
 			config->state->spi_read_ctx.buffer, read_count);
 
@@ -624,10 +628,14 @@ int usb_spi_interface(struct usb_spi_config const *config, usb_uint *rx_buf,
 	    (USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_INTERFACE))
 		return 1;
 
-	if (setup.wValue != 0 || setup.wIndex != config->interface ||
-	    setup.wLength != 0)
+	if (setup.wValue >= spi_devices_used ||
+	    !(spi_devices[setup.wValue].usb_flags & USB_SPI_ENABLED) ||
+	    setup.wIndex != config->interface || setup.wLength != 0)
 		return 1;
 
+	/* Record which SPI device the host wished to manipulate. */
+	config->state->current_spi_device_idx = setup.wValue;
+
 	switch (setup.bRequest) {
 	case USB_SPI_REQ_ENABLE:
 		config->state->enabled_host = 1;
diff --git a/chip/stm32/usb_spi.h b/chip/stm32/usb_spi.h
index 3ff582dd14..3f73efe9bc 100644
--- a/chip/stm32/usb_spi.h
+++ b/chip/stm32/usb_spi.h
@@ -280,6 +280,13 @@
 
 #define USB_SPI_MIN_PACKET_SIZE (2)
 
+/*
+ * Values used in spi_device_t.usb_flags
+ */
+
+/* Is the USB host allowed to operate on SPI device. */
+#define USB_SPI_ENABLED (BIT(0))
+
 enum packet_id_type {
 	/* Request USB SPI configuration data from device. */
 	USB_SPI_PKT_ID_CMD_GET_USB_SPI_CONFIG = 0,
@@ -457,8 +464,8 @@ struct usb_spi_state {
 	 * control endpoint.  The enabled_device flag is set by calling
 	 * usb_spi_enable.
 	 */
-	int enabled_host;
-	int enabled_device;
+	uint8_t enabled_host;
+	uint8_t enabled_device;
 
 	/*
 	 * The current enabled state.  This is only updated in the deferred
@@ -470,7 +477,13 @@ struct usb_spi_state {
 	 * specific state update routines are only called from the deferred
 	 * callback.
 	 */
-	int enabled;
+	uint8_t enabled;
+
+	/*
+	 * The index of the SPI port currently receiving forwarded transactions,
+	 * default is zero.
+	 */
+	uint8_t current_spi_device_idx;
 
 	/* Mark the current operating mode. */
 	enum usb_spi_mode mode;
@@ -554,6 +567,7 @@ struct usb_spi_config {
 		.enabled_host = 0,                                          \
 		.enabled_device = 0,                                        \
 		.enabled = 0,                                               \
+		.current_spi_device_idx = 0,                                \
 		.spi_write_ctx.buffer = (uint8_t *)CONCAT2(NAME, _buffer_), \
 		.spi_read_ctx.buffer = (uint8_t *)CONCAT2(NAME, _buffer_),  \
 	};                                                                  \
diff --git a/include/spi.h b/include/spi.h
index 965f941fa3..b6251b74b2 100644
--- a/include/spi.h
+++ b/include/spi.h
@@ -45,6 +45,13 @@ struct spi_device_t {
 
 	/* gpio used for chip selection. */
 	enum gpio_signal gpio_cs;
+
+#ifdef CONFIG_USB_SPI
+	/*
+	 * Flags used by usb_spi.c
+	 */
+	uint8_t usb_flags;
+#endif
 };
 
 extern