hammer: Make keyboard work at firmware screen

First, libpayload expects the keyboard interface index to be 0.

Then, hid_iface_request needs to reply to USB_HID_DT_HID request
with the content of struct usb_hid_descriptor. With current code,
the variable name is generated (and therefore hard to guess), so
we create a new set of macros so that we can use a specific
variable name.

Also, add support for HID Get_Protocol and Set_Protocol, as they
are compulsory for devices supporting boot protocol, even though
those are mostly no-op for now.

Finally, add a note regarding USB HID keyboard boot protocol, to
make sure that we do not accidentally change the report format.

BRANCH=none
BUG=b:36538963
TEST=Keyboard works in FW screen, both trackpad and keyboard
     still work when AP has booted.
TEST=hammer/staff can still be updated (both RO from RW, and RW
     from RO)

Change-Id: Ibea4888385909c9ce3b430464e5805c039d4b9ed
Reviewed-on: https://chromium-review.googlesource.com/505796
Commit-Ready: Nicolas Boichat <drinkcat@chromium.org>
Tested-by: Nicolas Boichat <drinkcat@chromium.org>
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>

1 files changed, 30 insertions, 19 deletions

diff --git a/chip/stm32/usb_hid.c b/chip/stm32/usb_hid.c
index 5561c8afad..4a89d9573c 100644
--- a/chip/stm32/usb_hid.c
+++ b/chip/stm32/usb_hid.c
@@ -17,6 +17,7 @@
 #include "usb_descriptor.h"
 #include "usb_hw.h"
 #include "usb_hid.h"
+#include "usb_hid_hw.h"
 
 /* Console output macro */
 #define CPRINTF(format, args...) cprintf(CC_USB, format, ## args)
@@ -49,7 +50,8 @@ static int report_left;
 static const uint8_t *report_ptr;
 
 int hid_iface_request(usb_uint *ep0_buf_rx, usb_uint *ep0_buf_tx,
-		      const uint8_t *report_desc, int report_size)
+		      const uint8_t *report_desc, int report_size,
+		      const struct usb_hid_descriptor *hid_desc)
 {
 	if (!ep0_buf_rx) {
 		/*
@@ -68,26 +70,35 @@ int hid_iface_request(usb_uint *ep0_buf_rx, usb_uint *ep0_buf_tx,
 		STM32_TOGGLE_EP(0, EP_TX_MASK, EP_TX_VALID,
 				report_left ? 0 : EP_STATUS_OUT);
 		return report_left ? 1 : 0;
-	} else if ((ep0_buf_rx[0] == (USB_DIR_IN | USB_RECIP_INTERFACE |
-			      (USB_REQ_GET_DESCRIPTOR << 8))) &&
-			      (ep0_buf_rx[1] == (USB_HID_DT_REPORT << 8))) {
-		/* Setup : HID specific : Get Report descriptor */
-		report_size = MIN(ep0_buf_rx[3], report_size);
+	} else if (ep0_buf_rx[0] == (USB_DIR_IN | USB_RECIP_INTERFACE |
+					(USB_REQ_GET_DESCRIPTOR << 8))) {
+		if (ep0_buf_rx[1] == (USB_HID_DT_REPORT << 8)) {
+			/* Setup : HID specific : Get Report descriptor */
+			report_size = MIN(ep0_buf_rx[3], report_size);
 
-		if (report_size > USB_MAX_PACKET_SIZE) {
-			/* Report descriptor does not fit in one packet. */
-			report_left = report_size - USB_MAX_PACKET_SIZE;
-			report_ptr = report_desc + USB_MAX_PACKET_SIZE;
-			report_size = USB_MAX_PACKET_SIZE;
-		} else {
-			report_left = 0;
+			if (report_size > USB_MAX_PACKET_SIZE) {
+				/* Report descriptor doesn't fit in 1 packet. */
+				report_left = report_size - USB_MAX_PACKET_SIZE;
+				report_ptr = report_desc + USB_MAX_PACKET_SIZE;
+				report_size = USB_MAX_PACKET_SIZE;
+			} else {
+				report_left = 0;
+			}
+			memcpy_to_usbram((void *) usb_sram_addr(ep0_buf_tx),
+					report_desc, report_size);
+			btable_ep[0].tx_count = report_size;
+			STM32_TOGGLE_EP(0, EP_TX_RX_MASK, EP_TX_RX_VALID,
+					report_left ? 0 : EP_STATUS_OUT);
+			return report_left ? 1 : 0;
+		} else if (ep0_buf_rx[1] == (USB_HID_DT_HID << 8)) {
+			/* Setup : HID specific : Get HID descriptor */
+			memcpy_to_usbram((void *) usb_sram_addr(ep0_buf_tx),
+					hid_desc, sizeof(*hid_desc));
+			btable_ep[0].tx_count = sizeof(*hid_desc);
+			STM32_TOGGLE_EP(0, EP_TX_RX_MASK, EP_TX_RX_VALID,
+					EP_STATUS_OUT);
+			return 0;
 		}
-		memcpy_to_usbram((void *) usb_sram_addr(ep0_buf_tx),
-				 report_desc, report_size);
-		btable_ep[0].tx_count = report_size;
-		STM32_TOGGLE_EP(0, EP_TX_RX_MASK, EP_TX_RX_VALID,
-				report_left ? 0 : EP_STATUS_OUT);
-		return report_left ? 1 : 0;
 	}
 
 	return -1;