usb_spi: add support for custom SYS_RST and EC_RST setup

Don't touch the SYS_RST_L or EC_RST_L signals when flashing the AP if
flashrom is run with custom_rst=True.

BUG=b:154885210
TEST=manual on bob
	ecrst on
	flashrom -p raiden_debug_spi:target=EC -r ec.bin

	ecrst on
	flashrom -p raiden_debug_spi:target=AP,custom_rst=True -r ap.bin
	check ecrst is still on

	flashrom -p raiden_debug_spi:target=AP -r ap.bin

Change-Id: Ia1ab8c853c25ced994e053c9e19a18d0d0f1cb45
Signed-off-by: Mary Ruthven <mruthven@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2301239
Reviewed-by: Vadim Bendebury <vbendeb@chromium.org>

2 files changed, 63 insertions, 23 deletions

diff --git a/board/cr50/usb_spi.c b/board/cr50/usb_spi.c
index 050ea63aac..a58e14789a 100644
--- a/board/cr50/usb_spi.c
+++ b/board/cr50/usb_spi.c
@@ -37,6 +37,12 @@
 /* Timeout for auto-disabling SPI hash device, in microseconds */
 #define SPI_HASH_TIMEOUT_US (60 * SECOND)
 
+/*
+ * If True, don't touch the reset signals while setting up AP usb spi. This
+ * doesn't affect spi hash.
+ */
+static uint8_t usb_spi_custom_reset;
+
 /* Current device for SPI hashing */
 static uint8_t spi_hash_device = USB_SPI_DISABLE;
 
@@ -146,7 +152,7 @@ static enum spi_bus_user_t get_spi_bus_user(void)
 /*****************************************************************************/
 /* Methods to enable / disable the SPI bus and pin mux */
 
-static void disable_ec_ap_spi(void)
+static void disable_ec_ap_spi(uint8_t custom_reset)
 {
 	int was_ap_spi_en = gpio_get_level(GPIO_AP_FLASH_SELECT);
 
@@ -160,8 +166,15 @@ static void disable_ec_ap_spi(void)
 		 * held in reset.  Therefore, it needs to be released here.
 		 */
 		gpio_set_level(GPIO_AP_FLASH_SELECT, 0);
-		deassert_ec_rst();
-		deassert_sys_rst();
+		/*
+		 * Some boards require special EC_RST_L SYS_RST_L behavior.
+		 * Don't touch the signals if the user requested custom reset
+		 * behavior.
+		 */
+		if (!custom_reset) {
+			deassert_ec_rst();
+			deassert_sys_rst();
+		}
 	}
 }
 
@@ -178,7 +191,7 @@ static void enable_ec_spi(void)
 	 */
 }
 
-static void enable_ap_spi(void)
+static void enable_ap_spi(uint8_t custom_reset)
 {
 	/* Select AP flash */
 	gpio_set_level(GPIO_AP_FLASH_SELECT, 1);
@@ -187,8 +200,11 @@ static void enable_ap_spi(void)
 	/*
 	 * On some systems SYS_RST_L is not level sensitive, so the only way to
 	 * be sure we're holding the AP in reset is to hold the EC in reset.
+	 * Don't touch the reset signals if the user requested a custom reset
+	 * setup.
 	 */
-	assert_ec_rst();
+	if (!custom_reset)
+		assert_ec_rst();
 }
 
 /**
@@ -245,9 +261,12 @@ static void disable_spi_pinmux(void)
 /*****************************************************************************/
 /* USB SPI methods */
 
-int usb_spi_board_enable(int host)
+/*
+ * Check that the CCD capability for the host is enabled and the SPI bus isn't
+ * active.
+ */
+static int usb_spi_check_host_accessible(int host)
 {
-	/* Make sure we're allowed to enable the requested device */
 	if (host == USB_SPI_EC) {
 		if (!ccd_is_cap_enabled(CCD_CAP_EC_FLASH)) {
 			CPRINTS("%s: EC access denied", __func__);
@@ -267,8 +286,20 @@ int usb_spi_board_enable(int host)
 		CPRINTS("%s: bus in use", __func__);
 		return EC_ERROR_BUSY;
 	}
+	return EC_SUCCESS;
+}
 
-	disable_ec_ap_spi();
+int usb_spi_board_enable(int host)
+{
+	/* Make sure we're allowed to enable the requested device */
+	int rv = usb_spi_check_host_accessible(host);
+
+	if (rv != EC_SUCCESS) {
+		usb_spi_custom_reset = 0;
+		return rv;
+	}
+
+	disable_ec_ap_spi(usb_spi_custom_reset);
 
 	/*
 	 * Only need to check EC vs. AP, because other hosts were ruled out
@@ -277,7 +308,7 @@ int usb_spi_board_enable(int host)
 	if (host == USB_SPI_EC)
 		enable_ec_spi();
 	else
-		enable_ap_spi();
+		enable_ap_spi(usb_spi_custom_reset);
 
 	enable_spi_pinmux();
 	return EC_SUCCESS;
@@ -292,7 +323,8 @@ void usb_spi_board_disable(void)
 		return;
 
 	disable_spi_pinmux();
-	disable_ec_ap_spi();
+	disable_ec_ap_spi(usb_spi_custom_reset);
+	usb_spi_custom_reset = 0;
 	set_spi_bus_user(SPI_BUS_USER_USB, 0);
 }
 
@@ -313,13 +345,20 @@ int usb_spi_interface(struct usb_spi_config const *config,
 		return 1;
 
 	switch (req->bRequest) {
+	case USB_SPI_REQ_ENABLE_AP_CUSTOM:
+		usb_spi_custom_reset = 1;
+		config->state->enabled_host = USB_SPI_AP;
+		break;
 	case USB_SPI_REQ_ENABLE_AP:
+		usb_spi_custom_reset = 0;
 		config->state->enabled_host = USB_SPI_AP;
 		break;
 	case USB_SPI_REQ_ENABLE_EC:
+		usb_spi_custom_reset = 0;
 		config->state->enabled_host = USB_SPI_EC;
 		break;
 	case USB_SPI_REQ_ENABLE:
+		usb_spi_custom_reset = 0;
 		CPRINTS("%s: Must specify target", __func__);
 		/* Fall through... */
 	case USB_SPI_REQ_DISABLE:
@@ -409,7 +448,7 @@ static enum vendor_cmd_rc spi_hash_disable(void)
 
 	/* Disable the SPI bus and chip select */
 	disable_spi_pinmux();
-	disable_ec_ap_spi();
+	disable_ec_ap_spi(0);
 
 	/* Stop the EC device, if it was active */
 	spi_hash_stop_ec_device();
@@ -448,14 +487,14 @@ static void spi_hash_pp_done(void)
 
 	/* Clear previous enable if needed */
 	if (spi_hash_device != USB_SPI_DISABLE)
-		disable_ec_ap_spi();
+		disable_ec_ap_spi(0);
 
 	/* Set up new device */
 	if (spi_hash_new_device == USB_SPI_AP) {
 		/* Stop the EC device, if it was previously active */
 		spi_hash_stop_ec_device();
 
-		enable_ap_spi();
+		enable_ap_spi(0);
 	} else {
 		/* Force the EC into reset and enable EC SPI bus */
 		assert_ec_rst();
diff --git a/chip/g/usb_spi.h b/chip/g/usb_spi.h
index 7a3d5652b3..65be060616 100644
--- a/chip/g/usb_spi.h
+++ b/chip/g/usb_spi.h
@@ -63,16 +63,17 @@ enum usb_spi_error {
 };
 
 enum usb_spi_request {
-	USB_SPI_REQ_ENABLE          = 0x0000,
-	USB_SPI_REQ_DISABLE         = 0x0001,
-	USB_SPI_REQ_ENABLE_AP       = 0x0002,
-	USB_SPI_REQ_ENABLE_EC       = 0x0003,
-	USB_SPI_REQ_ENABLE_H1       = 0x0004,
-	USB_SPI_REQ_RESET           = 0x0005,
-	USB_SPI_REQ_BOOT_CFG        = 0x0006,
-	USB_SPI_REQ_SOCKET          = 0x0007,
-	USB_SPI_REQ_SIGNING_START   = 0x0008,
-	USB_SPI_REQ_SIGNING_SIGN    = 0x0009,
+	USB_SPI_REQ_ENABLE           = 0x0000,
+	USB_SPI_REQ_DISABLE          = 0x0001,
+	USB_SPI_REQ_ENABLE_AP        = 0x0002,
+	USB_SPI_REQ_ENABLE_EC        = 0x0003,
+	USB_SPI_REQ_ENABLE_H1        = 0x0004,
+	USB_SPI_REQ_RESET            = 0x0005,
+	USB_SPI_REQ_BOOT_CFG         = 0x0006,
+	USB_SPI_REQ_SOCKET           = 0x0007,
+	USB_SPI_REQ_SIGNING_START    = 0x0008,
+	USB_SPI_REQ_SIGNING_SIGN     = 0x0009,
+	USB_SPI_REQ_ENABLE_AP_CUSTOM = 0x000a,
 };
 
 /* USB SPI device bitmasks */