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>

1 files changed, 21 insertions, 1 deletions

diff --git a/drivers/usb/host/uhci-platform.c b/drivers/usb/host/uhci-platform.c
index 32a6f3d8deec..1b4e086c33a0 100644
--- a/drivers/usb/host/uhci-platform.c
+++ b/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;