usb: chipidea: tegra: Support host mode

Add USB host mode to the Tegra HDRC driver. This allows us to benefit from
support provided by the generic ChipIdea driver instead of duplicating the
effort in a separate ehci-tegra driver.

Tested-by: Matt Merhar <[e-mail]>
Tested-by: Nicolas Chauvet <[e-mail]>
Tested-by: Ion Agorria <[e-mail]>
Acked-by: Thierry Reding <[e-mail]>
Acked-by: Peter Chen <[e-mail]>
Signed-off-by: Peter Geis <[e-mail]>
Signed-off-by: Dmitry Osipenko <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/chipidea/Kconfig

···
 config USB_CHIPIDEA_TEGRA
 	tristate "Enable Tegra USB glue driver" if EMBEDDED
 	depends on OF
-	depends on USB_CHIPIDEA_UDC
 	default USB_CHIPIDEA
 
 endif

drivers/usb/chipidea/ci_hdrc_tegra.c

···
  */
 
 #include <linux/clk.h>
+#include <linux/io.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/reset.h>
 
+#include <linux/usb.h>
 #include <linux/usb/chipidea.h>
+#include <linux/usb/hcd.h>
+#include <linux/usb/of.h>
+#include <linux/usb/phy.h>
+
+#include "../host/ehci.h"
 
 #include "ci.h"
 
···
 	struct ci_hdrc_platform_data data;
 	struct platform_device *dev;
 
+	const struct tegra_usb_soc_info *soc;
 	struct usb_phy *phy;
 	struct clk *clk;
+
+	bool needs_double_reset;
 };
 
 struct tegra_usb_soc_info {
 	unsigned long flags;
+	unsigned int txfifothresh;
+	enum usb_dr_mode dr_mode;
+};
+
+static const struct tegra_usb_soc_info tegra20_ehci_soc_info = {
+	.flags = CI_HDRC_REQUIRES_ALIGNED_DMA |
+		 CI_HDRC_OVERRIDE_PHY_CONTROL,
+	.dr_mode = USB_DR_MODE_HOST,
+	.txfifothresh = 10,
+};
+
+static const struct tegra_usb_soc_info tegra30_ehci_soc_info = {
+	.flags = CI_HDRC_REQUIRES_ALIGNED_DMA |
+		 CI_HDRC_OVERRIDE_PHY_CONTROL,
+	.dr_mode = USB_DR_MODE_HOST,
+	.txfifothresh = 16,
 };
 
 static const struct tegra_usb_soc_info tegra_udc_soc_info = {
-	.flags = CI_HDRC_REQUIRES_ALIGNED_DMA,
+	.flags = CI_HDRC_REQUIRES_ALIGNED_DMA |
+		 CI_HDRC_OVERRIDE_PHY_CONTROL,
+	.dr_mode = USB_DR_MODE_UNKNOWN,
 };
 
 static const struct of_device_id tegra_usb_of_match[] = {
 	{
+		.compatible = "nvidia,tegra20-ehci",
+		.data = &tegra20_ehci_soc_info,
+	}, {
+		.compatible = "nvidia,tegra30-ehci",
+		.data = &tegra30_ehci_soc_info,
+	}, {
 		.compatible = "nvidia,tegra20-udc",
 		.data = &tegra_udc_soc_info,
 	}, {
···
 	}
 };
 MODULE_DEVICE_TABLE(of, tegra_usb_of_match);
+
+static int tegra_usb_reset_controller(struct device *dev)
+{
+	struct reset_control *rst, *rst_utmi;
+	struct device_node *phy_np;
+	int err;
+
+	rst = devm_reset_control_get_shared(dev, "usb");
+	if (IS_ERR(rst)) {
+		dev_err(dev, "can't get ehci reset: %pe\n", rst);
+		return PTR_ERR(rst);
+	}
+
+	phy_np = of_parse_phandle(dev->of_node, "nvidia,phy", 0);
+	if (!phy_np)
+		return -ENOENT;
+
+	/*
+	 * The 1st USB controller contains some UTMI pad registers that are
+	 * global for all the controllers on the chip. Those registers are
+	 * also cleared when reset is asserted to the 1st controller.
+	 */
+	rst_utmi = of_reset_control_get_shared(phy_np, "utmi-pads");
+	if (IS_ERR(rst_utmi)) {
+		dev_warn(dev, "can't get utmi-pads reset from the PHY\n");
+		dev_warn(dev, "continuing, but please update your DT\n");
+	} else {
+		/*
+		 * PHY driver performs UTMI-pads reset in a case of a
+		 * non-legacy DT.
+		 */
+		reset_control_put(rst_utmi);
+	}
+
+	of_node_put(phy_np);
+
+	/* reset control is shared, hence initialize it first */
+	err = reset_control_deassert(rst);
+	if (err)
+		return err;
+
+	err = reset_control_assert(rst);
+	if (err)
+		return err;
+
+	udelay(1);
+
+	err = reset_control_deassert(rst);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static int tegra_usb_notify_event(struct ci_hdrc *ci, unsigned int event)
+{
+	struct tegra_usb *usb = dev_get_drvdata(ci->dev->parent);
+	struct ehci_hcd *ehci;
+
+	switch (event) {
+	case CI_HDRC_CONTROLLER_RESET_EVENT:
+		if (ci->hcd) {
+			ehci = hcd_to_ehci(ci->hcd);
+			ehci->has_tdi_phy_lpm = false;
+			ehci_writel(ehci, usb->soc->txfifothresh << 16,
+				    &ehci->regs->txfill_tuning);
+		}
+		break;
+	}
+
+	return 0;
+}
+
+static int tegra_usb_internal_port_reset(struct ehci_hcd *ehci,
+					 u32 __iomem *portsc_reg,
+					 unsigned long *flags)
+{
+	u32 saved_usbintr, temp;
+	unsigned int i, tries;
+	int retval = 0;
+
+	saved_usbintr = ehci_readl(ehci, &ehci->regs->intr_enable);
+	/* disable USB interrupt */
+	ehci_writel(ehci, 0, &ehci->regs->intr_enable);
+	spin_unlock_irqrestore(&ehci->lock, *flags);
+
+	/*
+	 * Here we have to do Port Reset at most twice for
+	 * Port Enable bit to be set.
+	 */
+	for (i = 0; i < 2; i++) {
+		temp = ehci_readl(ehci, portsc_reg);
+		temp |= PORT_RESET;
+		ehci_writel(ehci, temp, portsc_reg);
+		fsleep(10000);
+		temp &= ~PORT_RESET;
+		ehci_writel(ehci, temp, portsc_reg);
+		fsleep(1000);
+		tries = 100;
+		do {
+			fsleep(1000);
+			/*
+			 * Up to this point, Port Enable bit is
+			 * expected to be set after 2 ms waiting.
+			 * USB1 usually takes extra 45 ms, for safety,
+			 * we take 100 ms as timeout.
+			 */
+			temp = ehci_readl(ehci, portsc_reg);
+		} while (!(temp & PORT_PE) && tries--);
+		if (temp & PORT_PE)
+			break;
+	}
+	if (i == 2)
+		retval = -ETIMEDOUT;
+
+	/*
+	 * Clear Connect Status Change bit if it's set.
+	 * We can't clear PORT_PEC. It will also cause PORT_PE to be cleared.
+	 */
+	if (temp & PORT_CSC)
+		ehci_writel(ehci, PORT_CSC, portsc_reg);
+
+	/*
+	 * Write to clear any interrupt status bits that might be set
+	 * during port reset.
+	 */
+	temp = ehci_readl(ehci, &ehci->regs->status);
+	ehci_writel(ehci, temp, &ehci->regs->status);
+
+	/* restore original interrupt-enable bits */
+	spin_lock_irqsave(&ehci->lock, *flags);
+	ehci_writel(ehci, saved_usbintr, &ehci->regs->intr_enable);
+
+	return retval;
+}
+
+static int tegra_ehci_hub_control(struct ci_hdrc *ci, u16 typeReq, u16 wValue,
+				  u16 wIndex, char *buf, u16 wLength,
+				  bool *done, unsigned long *flags)
+{
+	struct tegra_usb *usb = dev_get_drvdata(ci->dev->parent);
+	struct ehci_hcd *ehci = hcd_to_ehci(ci->hcd);
+	u32 __iomem *status_reg;
+	int retval = 0;
+
+	status_reg = &ehci->regs->port_status[(wIndex & 0xff) - 1];
+
+	switch (typeReq) {
+	case SetPortFeature:
+		if (wValue != USB_PORT_FEAT_RESET || !usb->needs_double_reset)
+			break;
+
+		/* for USB1 port we need to issue Port Reset twice internally */
+		retval = tegra_usb_internal_port_reset(ehci, status_reg, flags);
+		*done  = true;
+		break;
+	}
+
+	return retval;
+}
+
+static void tegra_usb_enter_lpm(struct ci_hdrc *ci, bool enable)
+{
+	/*
+	 * Touching any register which belongs to AHB clock domain will
+	 * hang CPU if USB controller is put into low power mode because
+	 * AHB USB clock is gated on Tegra in the LPM.
+	 *
+	 * Tegra PHY has a separate register for checking the clock status
+	 * and usb_phy_set_suspend() takes care of gating/ungating the clocks
+	 * and restoring the PHY state on Tegra. Hence DEVLC/PORTSC registers
+	 * shouldn't be touched directly by the CI driver.
+	 */
+	usb_phy_set_suspend(ci->usb_phy, enable);
+}
 
 static int tegra_usb_probe(struct platform_device *pdev)
 {
···
 		return err;
 	}
 
+	if (device_property_present(&pdev->dev, "nvidia,needs-double-reset"))
+		usb->needs_double_reset = true;
+
+	err = tegra_usb_reset_controller(&pdev->dev);
+	if (err) {
+		dev_err(&pdev->dev, "failed to reset controller: %d\n", err);
+		goto fail_power_off;
+	}
+
+	/*
+	 * USB controller registers shouldn't be touched before PHY is
+	 * initialized, otherwise CPU will hang because clocks are gated.
+	 * PHY driver controls gating of internal USB clocks on Tegra.
+	 */
+	err = usb_phy_init(usb->phy);
+	if (err)
+		goto fail_power_off;
+
+	platform_set_drvdata(pdev, usb);
+
 	/* setup and register ChipIdea HDRC device */
+	usb->soc = soc;
 	usb->data.name = "tegra-usb";
 	usb->data.flags = soc->flags;
 	usb->data.usb_phy = usb->phy;
+	usb->data.dr_mode = soc->dr_mode;
 	usb->data.capoffset = DEF_CAPOFFSET;
+	usb->data.enter_lpm = tegra_usb_enter_lpm;
+	usb->data.hub_control = tegra_ehci_hub_control;
+	usb->data.notify_event = tegra_usb_notify_event;
 
 	usb->dev = ci_hdrc_add_device(&pdev->dev, pdev->resource,
 				      pdev->num_resources, &usb->data);
 	if (IS_ERR(usb->dev)) {
 		err = PTR_ERR(usb->dev);
 		dev_err(&pdev->dev, "failed to add HDRC device: %d\n", err);
-		goto fail_power_off;
+		goto phy_shutdown;
 	}
-
-	platform_set_drvdata(pdev, usb);
 
 	return 0;
 
+phy_shutdown:
+	usb_phy_shutdown(usb->phy);
 fail_power_off:
 	clk_disable_unprepare(usb->clk);
 	return err;
···
 	struct tegra_usb *usb = platform_get_drvdata(pdev);
 
 	ci_hdrc_remove_device(usb->dev);
+	usb_phy_shutdown(usb->phy);
 	clk_disable_unprepare(usb->clk);
 
 	return 0;

drivers/usb/chipidea/core.c

···
 }
 
 /* The PHY enters/leaves low power mode */
-static void ci_hdrc_enter_lpm(struct ci_hdrc *ci, bool enable)
+static void ci_hdrc_enter_lpm_common(struct ci_hdrc *ci, bool enable)
 {
 	enum ci_hw_regs reg = ci->hw_bank.lpm ? OP_DEVLC : OP_PORTSC;
 	bool lpm = !!(hw_read(ci, reg, PORTSC_PHCD(ci->hw_bank.lpm)));
···
 	else if (!enable && lpm)
 		hw_write(ci, reg, PORTSC_PHCD(ci->hw_bank.lpm),
 				0);
+}
+
+static void ci_hdrc_enter_lpm(struct ci_hdrc *ci, bool enable)
+{
+	return ci->platdata->enter_lpm(ci, enable);
 }
 
 static int hw_device_init(struct ci_hdrc *ci, void __iomem *base)
···
 		if (!IS_ERR(p))
 			platdata->pins_device = p;
 	}
+
+	if (!platdata->enter_lpm)
+		platdata->enter_lpm = ci_hdrc_enter_lpm_common;
 
 	return 0;
 }

drivers/usb/chipidea/host.c

···
 	bool enabled;
 };
 
+struct ci_hdrc_dma_aligned_buffer {
+	void *kmalloc_ptr;
+	void *old_xfer_buffer;
+	u8 data[0];
+};
+
 static int ehci_ci_portpower(struct usb_hcd *hcd, int portnum, bool enable)
 {
 	struct ehci_hcd *ehci = hcd_to_ehci(hcd);
···
 		pinctrl_select_state(ci->platdata->pctl,
 				     ci->platdata->pins_host);
 
+	ci->hcd = hcd;
+
 	ret = usb_add_hcd(hcd, 0, 0);
 	if (ret) {
+		ci->hcd = NULL;
 		goto disable_reg;
 	} else {
 		struct usb_otg *otg = &ci->otg;
-
-		ci->hcd = hcd;
 
 		if (ci_otg_is_fsm_mode(ci)) {
 			otg->host = &hcd->self;
···
 	u32		temp;
 	unsigned long	flags;
 	int		retval = 0;
+	bool		done = false;
 	struct device *dev = hcd->self.controller;
 	struct ci_hdrc *ci = dev_get_drvdata(dev);
 
 	status_reg = &ehci->regs->port_status[(wIndex & 0xff) - 1];
 
 	spin_lock_irqsave(&ehci->lock, flags);
+
+	if (ci->platdata->hub_control) {
+		retval = ci->platdata->hub_control(ci, typeReq, wValue, wIndex,
+						   buf, wLength, &done, &flags);
+		if (done)
+			goto done;
+	}
 
 	if (typeReq == SetPortFeature && wValue == USB_PORT_FEAT_SUSPEND) {
 		temp = ehci_readl(ehci, status_reg);
···
 	return 0;
 }
 
+static void ci_hdrc_free_dma_aligned_buffer(struct urb *urb)
+{
+	struct ci_hdrc_dma_aligned_buffer *temp;
+	size_t length;
+
+	if (!(urb->transfer_flags & URB_ALIGNED_TEMP_BUFFER))
+		return;
+
+	temp = container_of(urb->transfer_buffer,
+			    struct ci_hdrc_dma_aligned_buffer, data);
+
+	if (usb_urb_dir_in(urb)) {
+		if (usb_pipeisoc(urb->pipe))
+			length = urb->transfer_buffer_length;
+		else
+			length = urb->actual_length;
+
+		memcpy(temp->old_xfer_buffer, temp->data, length);
+	}
+	urb->transfer_buffer = temp->old_xfer_buffer;
+	kfree(temp->kmalloc_ptr);
+
+	urb->transfer_flags &= ~URB_ALIGNED_TEMP_BUFFER;
+}
+
+static int ci_hdrc_alloc_dma_aligned_buffer(struct urb *urb, gfp_t mem_flags)
+{
+	struct ci_hdrc_dma_aligned_buffer *temp, *kmalloc_ptr;
+	const unsigned int ci_hdrc_usb_dma_align = 32;
+	size_t kmalloc_size;
+
+	if (urb->num_sgs || urb->sg || urb->transfer_buffer_length == 0 ||
+	    !((uintptr_t)urb->transfer_buffer & (ci_hdrc_usb_dma_align - 1)))
+		return 0;
+
+	/* Allocate a buffer with enough padding for alignment */
+	kmalloc_size = urb->transfer_buffer_length +
+		       sizeof(struct ci_hdrc_dma_aligned_buffer) +
+		       ci_hdrc_usb_dma_align - 1;
+
+	kmalloc_ptr = kmalloc(kmalloc_size, mem_flags);
+	if (!kmalloc_ptr)
+		return -ENOMEM;
+
+	/* Position our struct dma_aligned_buffer such that data is aligned */
+	temp = PTR_ALIGN(kmalloc_ptr + 1, ci_hdrc_usb_dma_align) - 1;
+	temp->kmalloc_ptr = kmalloc_ptr;
+	temp->old_xfer_buffer = urb->transfer_buffer;
+	if (usb_urb_dir_out(urb))
+		memcpy(temp->data, urb->transfer_buffer,
+		       urb->transfer_buffer_length);
+	urb->transfer_buffer = temp->data;
+
+	urb->transfer_flags |= URB_ALIGNED_TEMP_BUFFER;
+
+	return 0;
+}
+
+static int ci_hdrc_map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
+				   gfp_t mem_flags)
+{
+	int ret;
+
+	ret = ci_hdrc_alloc_dma_aligned_buffer(urb, mem_flags);
+	if (ret)
+		return ret;
+
+	ret = usb_hcd_map_urb_for_dma(hcd, urb, mem_flags);
+	if (ret)
+		ci_hdrc_free_dma_aligned_buffer(urb);
+
+	return ret;
+}
+
+static void ci_hdrc_unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb)
+{
+	usb_hcd_unmap_urb_for_dma(hcd, urb);
+	ci_hdrc_free_dma_aligned_buffer(urb);
+}
+
 int ci_hdrc_host_init(struct ci_hdrc *ci)
 {
 	struct ci_role_driver *rdrv;
···
 	rdrv->irq	= host_irq;
 	rdrv->name	= "host";
 	ci->roles[CI_ROLE_HOST] = rdrv;
+
+	if (ci->platdata->flags & CI_HDRC_REQUIRES_ALIGNED_DMA) {
+		ci_ehci_hc_driver.map_urb_for_dma = ci_hdrc_map_urb_for_dma;
+		ci_ehci_hc_driver.unmap_urb_for_dma = ci_hdrc_unmap_urb_for_dma;
+	}
 
 	return 0;
 }

include/linux/usb/chipidea.h

···
 	struct pinctrl_state *pins_default;
 	struct pinctrl_state *pins_host;
 	struct pinctrl_state *pins_device;
+
+	/* platform-specific hooks */
+	int (*hub_control)(struct ci_hdrc *ci, u16 typeReq, u16 wValue,
+			   u16 wIndex, char *buf, u16 wLength,
+			   bool *done, unsigned long *flags);
+	void (*enter_lpm)(struct ci_hdrc *ci, bool enable);
 };
 
 /* Default offset of capability registers */