usb/uhci: Add support for Aspeed BMC SoCs

The Aspeed 2400/2500 families have a variant of UHCI which requires
some quirks to the driver to work:

 - The register offsets are different. We add a remapping helper.

 - All accesses have to be done via 32-bit loads and stores. We
   force all accessors to use readl/writel. This is of no consequence
   for reads as we never read "in the middle" of a register. For writes
   it also works fine as the registers only actually implement the bits
   we try to write (16-bit for the registers accessed with writew and
   8-bit for the register accessed with writeb), so always using a
   32-bit write will have no negative effect. We never do partial writes.

 - The resume detect interrupt is broken

 - The number of ports is (optionally) provided via the device-tree

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
--

v2. Remove the bulk of the #ifdef's

 drivers/usb/host/Kconfig         |  6 ++++-
 drivers/usb/host/uhci-hcd.c      | 17 +++++++++++---
 drivers/usb/host/uhci-hcd.h      | 51 ++++++++++++++++++++++++++++++++++++++++
 drivers/usb/host/uhci-platform.c | 22 ++++++++++++++++-
 4 files changed, 91 insertions(+), 5 deletions(-)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/Kconfig

@@ -627,7 +627,11 @@ config USB_UHCI_SUPPORT_NON_PCI_HC
 
 config USB_UHCI_PLATFORM
 	bool
-	default y if ARCH_VT8500
+	default y if (ARCH_VT8500 || ARCH_ASPEED)
+
+config USB_UHCI_ASPEED
+       bool
+       default y if ARCH_ASPEED
 
 config USB_UHCI_BIG_ENDIAN_MMIO
 	bool

drivers/usb/host/uhci-hcd.c

@@ -265,9 +265,13 @@ static void configure_hc(struct uhci_hcd *uhci)
 
 static int resume_detect_interrupts_are_broken(struct uhci_hcd *uhci)
 {
-	/* If we have to ignore overcurrent events then almost by definition
-	 * we can't depend on resume-detect interrupts. */
-	if (ignore_oc)
+	/*
+	 * If we have to ignore overcurrent events then almost by definition
+	 * we can't depend on resume-detect interrupts.
+	 *
+	 * Those interrupts also don't seem to work on ASpeed SoCs.
+	 */
+	if (ignore_oc || uhci_is_aspeed(uhci))
 		return 1;
 
 	return uhci->resume_detect_interrupts_are_broken ?
@@ -384,6 +388,13 @@ static void start_rh(struct uhci_hcd *uhci)
 {
 	uhci->is_stopped = 0;
 
+	/*
+	 * Clear stale status bits on Aspeed as we get a stale HCH
+	 * which causes problems later on
+	 */
+	if (uhci_is_aspeed(uhci))
+		uhci_writew(uhci, uhci_readw(uhci, USBSTS), USBSTS);
+
 	/* Mark it configured and running with a 64-byte max packet.
 	 * All interrupts are enabled, even though RESUME won't do anything.
 	 */

drivers/usb/host/uhci-hcd.h

@@ -48,6 +48,8 @@
 /* USB port status and control registers */
 #define USBPORTSC1	16
 #define USBPORTSC2	18
+#define USBPORTSC3	20
+#define USBPORTSC4	22
 #define   USBPORTSC_CCS		0x0001	/* Current Connect Status
 					 * ("device present") */
 #define   USBPORTSC_CSC		0x0002	/* Connect Status Change */
@@ -427,6 +429,7 @@ struct uhci_hcd {
 	unsigned int wait_for_hp:1;		/* Wait for HP port reset */
 	unsigned int big_endian_mmio:1;		/* Big endian registers */
 	unsigned int big_endian_desc:1;		/* Big endian descriptors */
+	unsigned int is_aspeed:1;		/* Aspeed impl. workarounds */
 
 	/* Support for port suspend/resume/reset */
 	unsigned long port_c_suspend;		/* Bit-arrays of ports */
@@ -490,6 +493,12 @@ struct urb_priv {
 #define PCI_VENDOR_ID_GENESYS		0x17a0
 #define PCI_DEVICE_ID_GL880S_UHCI	0x8083
 
+/* Aspeed SoC needs some quirks */
+static inline bool uhci_is_aspeed(const struct uhci_hcd *uhci)
+{
+	return IS_ENABLED(CONFIG_USB_UHCI_ASPEED) && uhci->is_aspeed;
+}
+
 /*
  * Functions used to access controller registers. The UCHI spec says that host
  * controller I/O registers are mapped into PCI I/O space. For non-PCI hosts
@@ -545,10 +554,42 @@ static inline void uhci_writeb(const struct uhci_hcd *uhci, u8 val, int reg)
 #define uhci_big_endian_mmio(u)		0
 #endif
 
+static inline int uhci_aspeed_reg(unsigned int reg)
+{
+	switch (reg) {
+	case USBCMD:
+		return 00;
+	case USBSTS:
+		return 0x04;
+	case USBINTR:
+		return 0x08;
+	case USBFRNUM:
+		return 0x80;
+	case USBFLBASEADD:
+		return 0x0c;
+	case USBSOF:
+		return 0x84;
+	case USBPORTSC1:
+		return 0x88;
+	case USBPORTSC2:
+		return 0x8c;
+	case USBPORTSC3:
+		return 0x90;
+	case USBPORTSC4:
+		return 0x94;
+	default:
+		pr_warn("UHCI: Unsupported register 0x%02x on Aspeed\n", reg);
+		/* Return an unimplemented register */
+		return 0x10;
+	}
+}
+
 static inline u32 uhci_readl(const struct uhci_hcd *uhci, int reg)
 {
 	if (uhci_has_pci_registers(uhci))
 		return inl(uhci->io_addr + reg);
+	else if (uhci_is_aspeed(uhci))
+		return readl(uhci->regs + uhci_aspeed_reg(reg));
 #ifdef CONFIG_USB_UHCI_BIG_ENDIAN_MMIO
 	else if (uhci_big_endian_mmio(uhci))
 		return readl_be(uhci->regs + reg);
@@ -561,6 +602,8 @@ static inline void uhci_writel(const struct uhci_hcd *uhci, u32 val, int reg)
 {
 	if (uhci_has_pci_registers(uhci))
 		outl(val, uhci->io_addr + reg);
+	else if (uhci_is_aspeed(uhci))
+		writel(val, uhci->regs + uhci_aspeed_reg(reg));
 #ifdef CONFIG_USB_UHCI_BIG_ENDIAN_MMIO
 	else if (uhci_big_endian_mmio(uhci))
 		writel_be(val, uhci->regs + reg);
@@ -573,6 +616,8 @@ static inline u16 uhci_readw(const struct uhci_hcd *uhci, int reg)
 {
 	if (uhci_has_pci_registers(uhci))
 		return inw(uhci->io_addr + reg);
+	else if (uhci_is_aspeed(uhci))
+		return readl(uhci->regs + uhci_aspeed_reg(reg));
 #ifdef CONFIG_USB_UHCI_BIG_ENDIAN_MMIO
 	else if (uhci_big_endian_mmio(uhci))
 		return readw_be(uhci->regs + reg);
@@ -585,6 +630,8 @@ static inline void uhci_writew(const struct uhci_hcd *uhci, u16 val, int reg)
 {
 	if (uhci_has_pci_registers(uhci))
 		outw(val, uhci->io_addr + reg);
+	else if (uhci_is_aspeed(uhci))
+		writel(val, uhci->regs + uhci_aspeed_reg(reg));
 #ifdef CONFIG_USB_UHCI_BIG_ENDIAN_MMIO
 	else if (uhci_big_endian_mmio(uhci))
 		writew_be(val, uhci->regs + reg);
@@ -597,6 +644,8 @@ static inline u8 uhci_readb(const struct uhci_hcd *uhci, int reg)
 {
 	if (uhci_has_pci_registers(uhci))
 		return inb(uhci->io_addr + reg);
+	else if (uhci_is_aspeed(uhci))
+		return readl(uhci->regs + uhci_aspeed_reg(reg));
 #ifdef CONFIG_USB_UHCI_BIG_ENDIAN_MMIO
 	else if (uhci_big_endian_mmio(uhci))
 		return readb_be(uhci->regs + reg);
@@ -609,6 +658,8 @@ static inline void uhci_writeb(const struct uhci_hcd *uhci, u8 val, int reg)
 {
 	if (uhci_has_pci_registers(uhci))
 		outb(val, uhci->io_addr + reg);
+	else if (uhci_is_aspeed(uhci))
+		writel(val, uhci->regs + uhci_aspeed_reg(reg));
 #ifdef CONFIG_USB_UHCI_BIG_ENDIAN_MMIO
 	else if (uhci_big_endian_mmio(uhci))
 		writeb_be(val, uhci->regs + reg);

drivers/usb/host/uhci-platform.c

@@ -15,7 +15,9 @@ static int uhci_platform_init(struct usb_hcd *hcd)
 {
 	struct uhci_hcd *uhci = hcd_to_uhci(hcd);
 
-	uhci->rh_numports = uhci_count_ports(hcd);
+	/* Probe number of ports if not already provided by DT */
+	if (!uhci->rh_numports)
+		uhci->rh_numports = uhci_count_ports(hcd);
 
 	/* Set up pointers to to generic functions */
 	uhci->reset_hc = uhci_generic_reset_hc;
@@ -63,6 +65,7 @@ static const struct hc_driver uhci_platform_hc_driver = {
 
 static int uhci_hcd_platform_probe(struct platform_device *pdev)
 {
+	struct device_node *np = pdev->dev.of_node;
 	struct usb_hcd *hcd;
 	struct uhci_hcd	*uhci;
 	struct resource *res;
@@ -98,6 +101,23 @@ static int uhci_hcd_platform_probe(struct platform_device *pdev)
 
 	uhci->regs = hcd->regs;
 
+	/* Grab some things from the device-tree */
+	if (np) {
+		u32 num_ports;
+
+		if (of_property_read_u32(np, "#ports", &num_ports) == 0) {
+			uhci->rh_numports = num_ports;
+			dev_info(&pdev->dev,
+				"Detected %d ports from device-tree\n",
+				num_ports);
+		}
+		if (of_device_is_compatible(np, "aspeed,ast2400-uhci") ||
+		    of_device_is_compatible(np, "aspeed,ast2500-uhci")) {
+			uhci->is_aspeed = 1;
+			dev_info(&pdev->dev,
+				 "Enabled Aspeed implementation workarounds\n");
+		}
+	}
 	ret = usb_add_hcd(hcd, pdev->resource[1].start, IRQF_SHARED);
 	if (ret)
 		goto err_rmr;