pcengines/apu1: Enable USB overcurrent detection.

The two external USB ports and the internal USB header have overcurrent
protection chips with the low-active overcurrent signal connected to the
chipset.

The power-on default for this register disables the software detection
of overcurrent conditions.

After setting the register Linux correctly shows the overcurrent
condition in the kernel log (tested by shorting the 5v and gnd lines on
J14 / the internal USB header):
[ 2015.229921] usb usb1-port3: over-current condition
[ 2015.449925] usb usb1-port4: over-current condition

Simlar for the external ports:
[  256.237916] usb usb1-port1: over-current condition
[  256.458084] usb usb1-port5: over-current condition

Note that each signal is shared between two ports:
usboc0#: External ports (port1/5)
usboc1#: Internal ports (port3/4)

Change-Id: I02d498053b8ec61dc206e74a96c4a1dcfd4fae92
Signed-off-by: Tobias Diedrich <ranma+coreboot@tdiedrich.de>
Reviewed-on: https://review.coreboot.org/14084
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Martin Roth <martinroth@google.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/src/mainboard/pcengines/apu1/mainboard.c b/src/mainboard/pcengines/apu1/mainboard.c
index f91e8799d8..f11d94b116 100644
--- a/src/mainboard/pcengines/apu1/mainboard.c
+++ b/src/mainboard/pcengines/apu1/mainboard.c
@@ -230,6 +230,36 @@ const char *smbios_mainboard_serial_number(void)
 	return serial;
 }
 
+/*
+ * Set up "Over Current Control 1" (reg 0x58) on the first OHCI device.
+ * The remaining ports on the second device are for mcpie2/sdcard and
+ * can stay at the power-on default value.
+ *
+ * The schematic shows this transposed mapping for the first device:
+ * chipset port 0 -> port 1 (j12 external 2, usboc0#)
+ * chipset port 1 -> port 4 (j17 mpcie1)
+ * chipset port 2 -> port 2 (j14 header row1, usboc1#)
+ * chipset port 3 -> port 3 (j14 header row2, usboc1#)
+ * chipset port 4 -> port 0 (j12 external 1. usboc0#)
+ *
+ * Register mapping:
+ * bit0-3: Mapping for HS Port 0
+ * bit4-7: Mapping for HS Port 1
+ * bit8-11: Mapping for HS Port 2
+ * bit12-15: Mapping for HS Port 3
+ * bit16-19: Mapping for HS Port 4
+ * bit20-31: Reserved (0)
+ *
+ * power-on default: 0xfffff
+ * A value >7 will disable the overcurrent detection.
+ */
+static void usb_oc_setup(void)
+{
+	device_t dev = dev_find_slot(0, PCI_DEVFN(0x12, 0));
+
+	pci_write_config32(dev, 0x58, 0x011f0);
+}
+
 static void mainboard_final(void *chip_info)
 {
 	u32 mmio_base;
@@ -245,6 +275,7 @@ static void mainboard_final(void *chip_info)
 	configure_gpio(mmio_base, GPIO_189, GPIO_FTN_1, GPIO_OUTPUT | GPIO_DATA_LOW);
 	configure_gpio(mmio_base, GPIO_190, GPIO_FTN_1, GPIO_OUTPUT | GPIO_DATA_HIGH);
 	configure_gpio(mmio_base, GPIO_191, GPIO_FTN_1, GPIO_OUTPUT | GPIO_DATA_HIGH);
+	usb_oc_setup();
 }
 
 struct chip_operations mainboard_ops = {