Cr50: Support USB SETCFG/GETCFG control transfers

This adds USB support to Set and Get the Device Configuration.
These control transfers are standard device requests that need to
be added in order to behave properly for USB suspend/resume (and
in general). Before this CL, the Get command always failed and
the Set command had no effect internally. With this CL it works.

Note that this particular change only supports ONE configuration
for the Cr50. If/when we add additional configuration
descriptors, we'll need to update it again.

BUG=chrome-os-partner:50721
BRANCH=none
TEST=make buildall; manual tests on Cr50

This CL includes a test program. Connect the Cr50 to the build
host, and use that program to read and change the configuration.

  cd test/usb_test
  make
  ./device_configuration
  ./device_configuration 0
  ./device_configuration 1
  ./device_configuration 2

You may need to use sudo if your device permissions aren't sufficient.

Change-Id: Id65e70265f0760b1b374005dfcddc88e66a933f6
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/335878
Reviewed-by: Scott Collyer <scollyer@chromium.org>

1 files changed, 38 insertions, 6 deletions

diff --git a/chip/g/usb.c b/chip/g/usb.c
index 4912b0d7ad..de028935fe 100644
--- a/chip/g/usb.c
+++ b/chip/g/usb.c
@@ -217,7 +217,7 @@ const struct usb_config_descriptor USB_CONF_DESC(conf) = {
 	.bDescriptorType = USB_DT_CONFIGURATION,
 	.wTotalLength = 0x0BAD,	 /* number of returned bytes, set at runtime */
 	.bNumInterfaces = USB_IFACE_COUNT,
-	.bConfigurationValue = 1,
+	.bConfigurationValue = 1,		/* Caution: hard-coded value */
 	.iConfiguration = USB_STR_VERSION,
 	.bmAttributes = 0x80,			/* bus powered */
 	.bMaxPower = 250,			/* MaxPower 500 mA */
@@ -306,6 +306,15 @@ static uint8_t ep0_in_buf[IN_BUF_SIZE];
 static struct g_usb_desc ep0_in_desc[NUM_IN_PACKETS_AT_ONCE];
 static struct g_usb_desc *cur_in_desc;
 
+/* Overall device state (USB 2.0 spec, section 9.1.1).
+ * We only need a few, though. */
+static enum {
+	DS_DEFAULT,
+	DS_ADDRESS,
+	DS_CONFIGURED,
+} device_state;
+static uint8_t configuration_value;
+
 /* Reset all this to a good starting state. */
 static void initialize_dma_buffers(void)
 {
@@ -585,8 +594,9 @@ static int handle_setup_with_in_stage(enum table_case tc,
 		break;
 	}
 	case USB_REQ_GET_CONFIGURATION:
-		/* TODO: We might need this to handle USB suspend properly */
-		return -1;
+		data = &configuration_value;
+		len = sizeof(configuration_value);
+		break;
 
 	case USB_REQ_SYNCH_FRAME:
 		/* Unimplemented */
@@ -697,11 +707,25 @@ static int handle_setup_with_no_data_stage(enum table_case tc,
 		 */
 		GWRITE_FIELD(USB, DCFG, DEVADDR, set_addr);
 		print_later("SETAD 0x%02x (%d)", set_addr, set_addr, 0, 0, 0);
+		device_state = DS_ADDRESS;
 		break;
 
 	case USB_REQ_SET_CONFIGURATION:
-		/* TODO: Sanity-check this? We only have one config, right? */
 		print_later("SETCFG 0x%x", req->wValue, 0, 0, 0, 0);
+		switch (req->wValue) {
+		case 0:
+			configuration_value = req->wValue;
+			device_state = DS_ADDRESS;
+			break;
+		case 1:	    /* Caution: Only one config descriptor TODAY */
+			/* TODO: All endpoints set to DATA0 toggle state */
+			configuration_value = req->wValue;
+			device_state = DS_CONFIGURED;
+			break;
+		default:
+			/* Nope. That's a paddlin. */
+			return -1;
+		}
 		break;
 
 	case USB_REQ_CLEAR_FEATURE:
@@ -836,7 +860,7 @@ static void ep0_interrupt(uint32_t intr_on_out, uint32_t intr_on_in)
 			/* I don't *think* we need to do this, unless we need
 			 * to transfer more data. Customer support agrees and
 			 * it shouldn't matter if the host is well-behaved, but
-			 * seems like we had issues without it.
+			 * it seems like we had issues without it.
 			 * TODO: Test this case until we know for sure. */
 			GR_USB_DIEPCTL(0) = DXEPCTL_EPENA;
 
@@ -935,6 +959,10 @@ static void ep0_reset(void)
 	GWRITE_FIELD(USB, DCFG, DEVADDR, 0);
 	initialize_dma_buffers();
 	expect_setup_packet();
+	/* Clear our internal state */
+	device_state = DS_DEFAULT;
+	configuration_value = 0;
+
 }
 
 /****************************************************************************/
@@ -1040,6 +1068,7 @@ static void usb_early_suspend(void)
 {
 	print_later("usb_early_suspend()", 0, 0, 0, 0, 0);
 }
+
 static void usb_suspend(void)
 {
 	print_later("usb_suspend()", 0, 0, 0, 0, 0);
@@ -1147,6 +1176,9 @@ void usb_disconnect(void)
 {
 	print_later("usb_disconnect()", 0, 0, 0, 0, 0);
 	GR_USB_DCTL |= DCTL_SFTDISCON;
+
+	device_state = DS_DEFAULT;
+	configuration_value = 0;
 }
 
 void usb_init(void)
@@ -1198,7 +1230,7 @@ void usb_init(void)
 	/* Global + DMA configuration */
 	/* TODO: What about the AHB Burst Length Field? It's 0 now. */
 	GR_USB_GAHBCFG = GAHBCFG_DMA_EN | GAHBCFG_GLB_INTR_EN |
-			 GAHBCFG_NP_TXF_EMP_LVL;
+		GAHBCFG_NP_TXF_EMP_LVL;
 
 	/* Be in disconnected state until we are ready */
 	usb_disconnect();