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From:   Krishna Kurapati <quic_kriskura@quicinc.com>
To:     Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        "Andy Gross" <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        "Konrad Dybcio" <konrad.dybcio@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Felipe Balbi <balbi@kernel.org>
CC:     <linux-usb@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-arm-msm@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <quic_pkondeti@quicinc.com>, <quic_ppratap@quicinc.com>,
        <quic_wcheng@quicinc.com>, <quic_jackp@quicinc.com>,
        <quic_harshq@quicinc.com>, <ahalaney@redhat.com>,
        Krishna Kurapati <quic_kriskura@quicinc.com>
Subject: [PATCH v8 3/9] usb: dwc3: core: Access XHCI address space temporarily to read port info
Date:   Sun, 14 May 2023 11:19:11 +0530
Message-ID: <20230514054917.21318-4-quic_kriskura@quicinc.com>
In-Reply-To: <20230514054917.21318-1-quic_kriskura@quicinc.com>
References: <20230514054917.21318-1-quic_kriskura@quicinc.com>
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Precedence: bulk

Currently host-only capable DWC3 controllers support Multiport.
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>
---
 drivers/usb/dwc3/core.c | 113 ++++++++++++++++++++++++++++++++++++++++
 drivers/usb/dwc3/core.h |  17 +++++-
 2 files changed, 129 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 0beaab932e7d..e983aef1fb93 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1767,6 +1767,104 @@ static int dwc3_get_clocks(struct dwc3 *dwc)
 	return 0;
 }
 
+/**
+ * dwc3_xhci_find_next_ext_cap - Find the offset of the extended capabilities
+ *					with capability ID id.
+ *
+ * @base:	PCI MMIO registers base address.
+ * @start:	address at which to start looking, (0 or HCC_PARAMS to start at
+ *		beginning of list)
+ * @id:		Extended capability ID to search for, or 0 for the next
+ *		capability
+ *
+ * Returns the offset of the next matching extended capability structure.
+ * Some capabilities can occur several times, e.g., the XHCI_EXT_CAPS_PROTOCOL,
+ * and this provides a way to find them all.
+ */
+static int dwc3_xhci_find_next_ext_cap(void __iomem *base, u32 start, int id)
+{
+	u32 val;
+	u32 next;
+	u32 offset;
+
+	offset = start;
+	if (!start || start == XHCI_HCC_PARAMS_OFFSET) {
+		val = readl(base + XHCI_HCC_PARAMS_OFFSET);
+		if (val == ~0)
+			return 0;
+		offset = XHCI_HCC_EXT_CAPS(val) << 2;
+		if (!offset)
+			return 0;
+	}
+	do {
+		val = readl(base + offset);
+		if (val == ~0)
+			return 0;
+		if (offset != start && (id == 0 || XHCI_EXT_CAPS_ID(val) == id))
+			return offset;
+
+		next = XHCI_EXT_CAPS_NEXT(val);
+		offset += next << 2;
+	} while (next);
+
+	return 0;
+}
+
+static int dwc3_read_port_info(struct dwc3 *dwc)
+{
+	void __iomem		*regs;
+	u32			offset;
+	u32			temp;
+	u8			major_revision;
+	int			ret = 0;
+
+	/*
+	 * Remap xHCI address space to access XHCI ext cap regs,
+	 * since it is needed to get port info.
+	 */
+	regs = ioremap(dwc->xhci_resources[0].start,
+				resource_size(&dwc->xhci_resources[0]));
+	if (IS_ERR(regs))
+		return PTR_ERR(regs);
+
+	offset = dwc3_xhci_find_next_ext_cap(regs, 0,
+					XHCI_EXT_CAPS_PROTOCOL);
+	while (offset) {
+		temp = readl(regs + offset);
+		major_revision = XHCI_EXT_PORT_MAJOR(temp);
+
+		temp = readl(regs + offset + 0x08);
+		if (major_revision == 0x03) {
+			dwc->num_usb3_ports += XHCI_EXT_PORT_COUNT(temp);
+		} else if (major_revision <= 0x02) {
+			dwc->num_usb2_ports += XHCI_EXT_PORT_COUNT(temp);
+		} else {
+			dev_err(dwc->dev,
+				"Unrecognized port major revision %d\n", major_revision);
+			ret = -EINVAL;
+			goto unmap_reg;
+		}
+
+		offset = dwc3_xhci_find_next_ext_cap(regs, offset,
+						XHCI_EXT_CAPS_PROTOCOL);
+	}
+
+	temp = readl(regs + DWC3_XHCI_HCSPARAMS1);
+	if (HCS_MAX_PORTS(temp) != (dwc->num_usb3_ports + dwc->num_usb2_ports)) {
+		dev_err(dwc->dev,
+			"Mismatched reported MAXPORTS (%d)\n", HCS_MAX_PORTS(temp));
+		ret = -EINVAL;
+		goto unmap_reg;
+	}
+
+	dev_dbg(dwc->dev,
+		"hs-ports: %d ss-ports: %d\n", dwc->num_usb2_ports, dwc->num_usb3_ports);
+
+unmap_reg:
+	iounmap(regs);
+	return ret;
+}
+
 static int dwc3_probe(struct platform_device *pdev)
 {
 	struct device		*dev = &pdev->dev;
@@ -1774,6 +1872,7 @@ static int dwc3_probe(struct platform_device *pdev)
 	void __iomem		*regs;
 	struct dwc3		*dwc;
 	int			ret;
+	unsigned int		hw_mode;
 
 	dwc = devm_kzalloc(dev, sizeof(*dwc), GFP_KERNEL);
 	if (!dwc)
@@ -1843,6 +1942,20 @@ static int dwc3_probe(struct platform_device *pdev)
 			goto err_disable_clks;
 	}
 
+	/*
+	 * Currently DWC3 controllers that are host-only capable
+	 * support Multiport
+	 */
+	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 d56457c02996..d3401963bc27 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -35,6 +35,17 @@
 
 #define DWC3_MSG_MAX	500
 
+/* Define XHCI Extcap register offsets for getting multiport info */
+#define XHCI_HCC_PARAMS_OFFSET	0x10
+#define DWC3_XHCI_HCSPARAMS1	0x04
+#define XHCI_EXT_CAPS_PROTOCOL	2
+#define XHCI_HCC_EXT_CAPS(x)    (((x) >> 16) & 0xffff)
+#define XHCI_EXT_CAPS_ID(x)     (((x) >> 0) & 0xff)
+#define XHCI_EXT_CAPS_NEXT(x)   (((x) >> 8) & 0xff)
+#define XHCI_EXT_PORT_MAJOR(x)  (((x) >> 24) & 0xff)
+#define XHCI_EXT_PORT_COUNT(x)  (((x) >> 8) & 0xff)
+#define HCS_MAX_PORTS(x)        (((x) >> 24) & 0x7f)
+
 /* Global constants */
 #define DWC3_PULL_UP_TIMEOUT	500	/* ms */
 #define DWC3_BOUNCE_SIZE	1024	/* size of a superspeed bulk */
@@ -1025,6 +1036,8 @@ struct dwc3_scratchpad_array {
  * @usb_psy: pointer to power supply interface.
  * @usb2_phy: pointer to USB2 PHY
  * @usb3_phy: pointer to USB3 PHY
+ * @num_usb2_ports: number of usb2 ports.
+ * @num_usb3_ports: number of usb3 ports.
  * @usb2_generic_phy: pointer to USB2 PHY
  * @usb3_generic_phy: pointer to USB3 PHY
  * @phys_ready: flag to indicate that PHYs are ready
@@ -1162,6 +1175,9 @@ struct dwc3 {
 	struct usb_phy		*usb2_phy;
 	struct usb_phy		*usb3_phy;
 
+	u8			num_usb2_ports;
+	u8			num_usb3_ports;
+
 	struct phy		*usb2_generic_phy;
 	struct phy		*usb3_generic_phy;
 
@@ -1649,5 +1665,4 @@ static inline int dwc3_ulpi_init(struct dwc3 *dwc)
 static inline void dwc3_ulpi_exit(struct dwc3 *dwc)
 { }
 #endif
-
 #endif /* __DRIVERS_USB_DWC3_CORE_H */
-- 
2.40.0