[PATCH v18 2/9] usb: dwc3: core: Access XHCI address space temporarily to read port info

[Krishna Kurapati <quic_kriskura@quicinc.com>]

All DWC3 Multi Port controllers that exist today only support host mode.
Temporarily map XHCI address space for host-only controllers and parse
XHCI Extended Capabilities registers to read number of usb2 ports and
usb3 ports present on multiport controller. Each USB Port is at least HS
capable.

The port info for usb2 and usb3 phy are identified as num_usb2_ports
and num_usb3_ports. The intention is as follows:

Wherever we need to perform phy operations like:

LOOP_OVER_NUMBER_OF_AVAILABLE_PORTS()
{
	phy_set_mode(dwc->usb2_generic_phy[i], PHY_MODE_USB_HOST);
	phy_set_mode(dwc->usb3_generic_phy[i], PHY_MODE_USB_HOST);
}

If number of usb2 ports is 3, loop can go from index 0-2 for
usb2_generic_phy. If number of usb3-ports is 2, we don't know for sure,
if the first 2 ports are SS capable or some other ports like (2 and 3)
are SS capable. So instead, num_usb2_ports is used to loop around all
phy's (both hs and ss) for performing phy operations. If any
usb3_generic_phy turns out to be NULL, phy operation just bails out.
num_usb3_ports is used to modify GUSB3PIPECTL registers while setting up
phy's as we need to know how many SS capable ports are there for this.

Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/usb/dwc3/core.c | 61 +++++++++++++++++++++++++++++++++++++++++
 drivers/usb/dwc3/core.h |  5 ++++
 2 files changed, 66 insertions(+)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 3e55838c0001..fab7664c12c0 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -39,6 +39,7 @@
 #include "io.h"
 
 #include "debug.h"
+#include "../host/xhci-ext-caps.h"
 
 #define DWC3_DEFAULT_AUTOSUSPEND_DELAY	5000 /* ms */
 
@@ -1879,10 +1880,56 @@ static int dwc3_get_clocks(struct dwc3 *dwc)
 	return 0;
 }
 
+static int dwc3_read_port_info(struct dwc3 *dwc)
+{
+	void __iomem *base;
+	u8 major_revision;
+	u32 offset;
+	u32 val;
+
+	/*
+	 * Remap xHCI address space to access XHCI ext cap regs since it is
+	 * needed to get information on number of ports present.
+	 */
+	base = ioremap(dwc->xhci_resources[0].start,
+		       resource_size(&dwc->xhci_resources[0]));
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	offset = 0;
+	do {
+		offset = xhci_find_next_ext_cap(base, offset,
+						XHCI_EXT_CAPS_PROTOCOL);
+		if (!offset)
+			break;
+
+		val = readl(base + offset);
+		major_revision = XHCI_EXT_PORT_MAJOR(val);
+
+		val = readl(base + offset + 0x08);
+		if (major_revision == 0x03) {
+			dwc->num_usb3_ports += XHCI_EXT_PORT_COUNT(val);
+		} else if (major_revision <= 0x02) {
+			dwc->num_usb2_ports += XHCI_EXT_PORT_COUNT(val);
+		} else {
+			dev_warn(dwc->dev, "unrecognized port major revision %d\n",
+				 major_revision);
+		}
+	} while (1);
+
+	dev_dbg(dwc->dev, "hs-ports: %u ss-ports: %u\n",
+		dwc->num_usb2_ports, dwc->num_usb3_ports);
+
+	iounmap(base);
+
+	return 0;
+}
+
 static int dwc3_probe(struct platform_device *pdev)
 {
 	struct device		*dev = &pdev->dev;
 	struct resource		*res, dwc_res;
+	unsigned int		hw_mode;
 	void __iomem		*regs;
 	struct dwc3		*dwc;
 	int			ret;
@@ -1966,6 +2013,20 @@ static int dwc3_probe(struct platform_device *pdev)
 			goto err_disable_clks;
 	}
 
+	/*
+	 * Currently only DWC3 controllers that are host-only capable
+	 * can have more than one port.
+	 */
+	hw_mode = DWC3_GHWPARAMS0_MODE(dwc->hwparams.hwparams0);
+	if (hw_mode == DWC3_GHWPARAMS0_MODE_HOST) {
+		ret = dwc3_read_port_info(dwc);
+		if (ret)
+			goto err_disable_clks;
+	} else {
+		dwc->num_usb2_ports = 1;
+		dwc->num_usb3_ports = 1;
+	}
+
 	spin_lock_init(&dwc->lock);
 	mutex_init(&dwc->mutex);
 
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index c07edfc954f7..40b00a895a2a 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -1039,6 +1039,8 @@ struct dwc3_scratchpad_array {
  * @usb3_phy: pointer to USB3 PHY
  * @usb2_generic_phy: pointer to USB2 PHY
  * @usb3_generic_phy: pointer to USB3 PHY
+ * @num_usb2_ports: number of USB2 ports
+ * @num_usb3_ports: number of USB3 ports
  * @phys_ready: flag to indicate that PHYs are ready
  * @ulpi: pointer to ulpi interface
  * @ulpi_ready: flag to indicate that ULPI is initialized
@@ -1186,6 +1188,9 @@ struct dwc3 {
 	struct phy		*usb2_generic_phy;
 	struct phy		*usb3_generic_phy;
 
+	u8			num_usb2_ports;
+	u8			num_usb3_ports;
+
 	bool			phys_ready;
 
 	struct ulpi		*ulpi;
-- 
2.34.1