libpayload/uhci: Re-write UHCI RH driver w/ generic_hub API

This is a complete rewrite of the UHCI root-hub driver, based on
the xHCI one. We are doing things by the book as far as possible.
One special case is uhci_rh_reset_port() which does the reset se-
quencing that usually the hardware would do.

This abandons some quirks of the old driver:
* Ports are not disabled/re-enabled for every attachment anymore.
* We solely rely on the Connect Status Change bit to track changes.
* Further status changes are now deferred to the next polling round.

The latter fixes endless loops in combination with commit 7faff543da
(libpayload: usb: Detach unused USB devices).

Change-Id: I5211728775eb94dfc23fa82ebf00fe5c99039709
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/75504
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>

1 files changed, 91 insertions, 152 deletions

diff --git a/payloads/libpayload/drivers/usb/uhci_rh.c b/payloads/libpayload/drivers/usb/uhci_rh.c
index e7f0da7666..5f3d184cfd 100644
--- a/payloads/libpayload/drivers/usb/uhci_rh.c
+++ b/payloads/libpayload/drivers/usb/uhci_rh.c
@@ -1,6 +1,6 @@
 /*
  *
- * Copyright (C) 2008-2010 coresystems GmbH
+ * Copyright (C) 2013 secunet Security Networks AG
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -28,184 +28,123 @@
 
 //#define USB_DEBUG
 
-#include <libpayload.h>
-#include "uhci.h"
+#include <stdint.h>
+#include <stdbool.h>
+#include <usb/usb.h>
+
+#include "generic_hub.h"
 #include "uhci_private.h"
+#include "uhci.h"
 
-typedef struct {
-	int port[2];
-} rh_inst_t;
+#define PORTSC(p) (PORTSC1 + ((p) - 1) * sizeof(uint16_t))
+#define  PORTSC_CCS	(1 << 0)
+#define  PORTSC_CSC	(1 << 1)
+#define  PORTSC_PED	(1 << 2)
+#define  PORTSC_PEDC	(1 << 3)
+#define  PORTSC_LSDA	(1 << 8)
+#define  PORTSC_PR	(1 << 9)
+#define  PORTSC_SUSP	(1 << 12)
+#define  PORTSC_SC_BITS (PORTSC_CSC | PORTSC_PEDC)
 
-#define RH_INST(dev) ((rh_inst_t*)(dev)->data)
+static int
+uhci_rh_port_status_changed(usbdev_t *const dev, const int port)
+{
+	const u16 portsc = uhci_reg_read16(dev->controller, PORTSC(port));
+	const bool changed = portsc & (PORTSC_CSC | PORTSC_PEDC);
+
+	/* always clear all the status change bits */
+	uhci_reg_write16(dev->controller, PORTSC(port), portsc);
 
-static void
-uhci_rh_enable_port(usbdev_t *dev, int port)
+	return changed;
+}
+
+static int
+uhci_rh_port_connected(usbdev_t *const dev, const int port)
 {
-	u16 value;
-	hci_t *controller = dev->controller;
-	if (port == 1)
-		port = PORTSC1;
-	else if (port == 2)
-		port = PORTSC2;
-	else {
-		usb_debug("Invalid port %d\n", port);
-		return;
-	}
-
-	uhci_reg_write16(controller, port,
-			 uhci_reg_read16(controller, port) & ~(1 << 12));	/* wakeup */
-
-	uhci_reg_write16(controller, port,
-			 uhci_reg_read16(controller, port) | 1 << 9);	/* reset */
-	mdelay(30);		// >10ms
-	uhci_reg_write16(controller, port,
-			 uhci_reg_read16(controller, port) & ~(1 << 9));
-	mdelay(1);		// >5.3us per spec, <3ms because some devices make trouble
-
-	uhci_reg_write16(controller, port,
-			 uhci_reg_read16(controller, port) | 1 << 2);	/* enable */
-	/* wait for controller to enable port */
-	/* TOTEST: how long to wait? 100ms for now */
-	int timeout = 200; /* time out after 200 * 500us == 100ms */
-	do {
-		value = uhci_reg_read16(controller, port);
-		udelay(500); timeout--;
-	} while (((value & (1 << 2)) == 0) && (value & 0x01) && timeout);
-	if (!timeout)
-		usb_debug("Warning: uhci_rh: port enabling timed out.\n");
+	const u16 portsc = uhci_reg_read16(dev->controller, PORTSC(port));
+	return !!(portsc & PORTSC_CCS);
 }
 
-/* disable root hub */
-static void
-uhci_rh_disable_port(usbdev_t *dev, int port)
+static int
+uhci_rh_port_enabled(usbdev_t *const dev, const int port)
 {
-	hci_t *controller = dev->controller;
-	if (port == 1)
-		port = PORTSC1;
-	else if (port == 2)
-		port = PORTSC2;
-	else {
-		usb_debug("Invalid port %d\n", port);
-		return;
-	}
-	uhci_reg_write16(controller, port,
-			 uhci_reg_read16(controller, port) & ~4);
-	u16 value;
-	/* wait for controller to disable port */
-	/* TOTEST: how long to wait? 100ms for now */
-	int timeout = 200; /* time out after 200 * 500us == 100ms */
-	do {
-		value = uhci_reg_read16(controller, port);
-		udelay(500); timeout--;
-	} while (((value & (1 << 2)) != 0) && timeout);
-	if (!timeout)
-		usb_debug("Warning: uhci_rh: port disabling timed out.\n");
+	const u16 portsc = uhci_reg_read16(dev->controller, PORTSC(port));
+	return !(portsc & PORTSC_SUSP) && (portsc & PORTSC_PED);
 }
 
-static void
-uhci_rh_scanport(usbdev_t *dev, int port)
+static usb_speed
+uhci_rh_port_speed(usbdev_t *const dev, const int port)
 {
-	int portsc, offset;
-	if (port == 1) {
-		portsc = PORTSC1;
-		offset = 0;
-	} else if (port == 2) {
-		portsc = PORTSC2;
-		offset = 1;
-	} else {
-		usb_debug("Invalid port %d\n", port);
-		return;
-	}
-	int devno = RH_INST(dev)->port[offset];
-	if ((devno != -1) && (dev->controller->devices[devno] != 0)) {
-		usb_detach_device(dev->controller, devno);
-		RH_INST(dev)->port[offset] = -1;
-	}
-	uhci_reg_write16(dev->controller, portsc,
-			 uhci_reg_read16(dev->controller, portsc) | (1 << 3) | (1 << 2));	// clear port state change, enable port
-
-	mdelay(100); // wait for signal to stabilize
-
-	if ((uhci_reg_read16(dev->controller, portsc) & 1) != 0) {
-		// device attached
-
-		uhci_rh_disable_port(dev, port);
-		uhci_rh_enable_port(dev, port);
-
-		usb_speed speed = ((uhci_reg_read16(dev->controller, portsc) >> 8) & 1);
-
-		RH_INST(dev)->port[offset] = usb_attach_device(dev->controller, dev->address, portsc, speed);
-	}
+	const u16 portsc = uhci_reg_read16(dev->controller, PORTSC(port));
+	const bool low_speed = portsc & PORTSC_LSDA;
+
+	return low_speed ? LOW_SPEED : FULL_SPEED;
 }
 
 static int
-uhci_rh_report_port_changes(usbdev_t *dev)
+uhci_rh_enable_port(usbdev_t *const dev, const int port)
 {
-	u16 stored, real;
-
-	stored = (RH_INST(dev)->port[0] == -1);
-	real = ((uhci_reg_read16(dev->controller, PORTSC1) & 1) == 0);
-	if (stored != real) {
-		usb_debug("change on port 1\n");
-		return 1;
-	}
-
-	stored = (RH_INST(dev)->port[1] == -1);
-	real = ((uhci_reg_read16(dev->controller, PORTSC2) & 1) == 0);
-	if (stored != real) {
-		usb_debug("change on port 2\n");
-		return 2;
-	}
-
-	// maybe detach+attach happened between two scans?
-
-	if ((uhci_reg_read16(dev->controller, PORTSC1) & 2) > 0) {
-		usb_debug("possibly re-attached on port 1\n");
-		return 1;
-	}
-	if ((uhci_reg_read16(dev->controller, PORTSC2) & 2) > 0) {
-		usb_debug("possibly re-attached on port 2\n");
-		return 2;
-	}
-
-	// no change
-	return -1;
+	const u16 portsc = uhci_reg_read16(dev->controller, PORTSC(port)) & ~PORTSC_SUSP;
+	uhci_reg_write16(dev->controller, PORTSC(port), portsc & ~(PORTSC_SC_BITS | PORTSC_SUSP));
+	uhci_reg_write16(dev->controller, PORTSC(port), (portsc & ~PORTSC_SC_BITS) | PORTSC_PED);
+	return 0;
 }
 
-static void
-uhci_rh_destroy(usbdev_t *dev)
+static int
+uhci_rh_disable_port(usbdev_t *const dev, const int port)
 {
-	usb_detach_device(dev->controller, 1);
-	usb_detach_device(dev->controller, 2);
-	uhci_rh_disable_port(dev, 1);
-	uhci_rh_disable_port(dev, 2);
-	free(RH_INST(dev));
+	const u16 portsc = uhci_reg_read16(dev->controller, PORTSC(port));
+	uhci_reg_write16(dev->controller, PORTSC(port), portsc & ~(PORTSC_SC_BITS | PORTSC_PED));
+	return 0;
 }
 
-static void
-uhci_rh_poll(usbdev_t *dev)
+static int
+uhci_rh_reset_port(usbdev_t *const dev, const int port)
 {
-	int port;
-	while ((port = uhci_rh_report_port_changes(dev)) != -1)
-		uhci_rh_scanport(dev, port);
+	const u16 portsc = uhci_reg_read16(dev->controller, PORTSC(port)) & ~PORTSC_PR;
+
+	/* Trigger port reset. */
+	uhci_reg_write16(dev->controller, PORTSC(port), portsc | PORTSC_PR);
+
+	/* Wait for 15ms (usb20 spec 11.5.1.5: reset should take 10 to 20ms). */
+	mdelay(15);
+
+	/* Clear port reset. */
+	uhci_reg_write16(dev->controller, PORTSC(port), portsc & ~PORTSC_PR);
+
+	udelay(10); /* Linux waits this long. */
+
+	/* Enable port. */
+	uhci_reg_write16(dev->controller, PORTSC(port), portsc | PORTSC_PED);
+
+	/* Clear status-change bits one last time. */
+	uhci_reg_write16(dev->controller, PORTSC(port), portsc | PORTSC_PED | PORTSC_SC_BITS);
+
+	return 0;
 }
 
+static const generic_hub_ops_t uhci_rh_ops = {
+	.hub_status_changed	= NULL,
+	.port_status_changed	= uhci_rh_port_status_changed,
+	.port_connected		= uhci_rh_port_connected,
+	.port_in_reset		= NULL,
+	.port_enabled		= uhci_rh_port_enabled,
+	.port_speed		= uhci_rh_port_speed,
+	.enable_port		= uhci_rh_enable_port,
+	.disable_port		= uhci_rh_disable_port,
+	.start_port_reset	= NULL,
+	.reset_port		= uhci_rh_reset_port,
+};
+
 void
 uhci_rh_init(usbdev_t *dev)
 {
-	dev->destroy = uhci_rh_destroy;
-	dev->poll = uhci_rh_poll;
-
-	uhci_rh_enable_port(dev, 1);
-	uhci_rh_enable_port(dev, 2);
-	dev->data = xmalloc(sizeof(rh_inst_t));
-
-	RH_INST(dev)->port[0] = -1;
-	RH_INST(dev)->port[1] = -1;
-
-	/* we can set them here because a root hub _really_ shouldn't
-	   appear elsewhere */
+	/* we can set them here because a root hub _really_ shouldn't appear elsewhere */
 	dev->address = 0;
 	dev->hub = -1;
 	dev->port = -1;
+
+	generic_hub_init(dev, 2, &uhci_rh_ops);
+
+	usb_debug("UHCI: root hub init done\n");
 }