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linux/drivers/usb/dwc2/drd.c
Ziyang Huang 82f5332d3b usb: dwc2: drd: fix inconsistent mode if role-switch-default-mode="host" 
Some boards might use USB-A female connector for USB ports, however,
the port could be connected to a dual-mode USB controller, making it
also behaves as a peripheral device if male-to-male cable is connected.

In this case, the dts looks like this:

	&usb0 {
		status = "okay";
		dr_mode = "otg";
		usb-role-switch;
		role-switch-default-mode = "host";
	};

After boot, dwc2_ovr_init() sets GOTGCTL to GOTGCTL_AVALOVAL and call
dwc2_force_mode() with parameter host=false, which causes inconsistent
mode - The hardware is in peripheral mode while the kernel status is
in host mode.

What we can do now is to call dwc2_drd_role_sw_set() to switch to
device mode, and everything should work just fine now, even switching
back to none(default) mode afterwards.

Fixes: e14acb8769 ("usb: dwc2: drd: add role-switch-default-node support")
Cc: stable <stable@kernel.org>
Signed-off-by: Ziyang Huang <hzyitc@outlook.com>
Tested-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Acked-by: Minas Harutyunyan <hminas@synopsys.com>
Reviewed-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Link: https://lore.kernel.org/r/SG2PR01MB204837BF68EDB0E343D2A375C9A59@SG2PR01MB2048.apcprd01.prod.exchangelabs.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-09 15:38:24 +01:00

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// SPDX-License-Identifier: GPL-2.0
/*
* drd.c - DesignWare USB2 DRD Controller Dual-role support
*
* Copyright (C) 2020 STMicroelectronics
*
* Author(s): Amelie Delaunay <amelie.delaunay@st.com>
*/
#include <linux/clk.h>
#include <linux/iopoll.h>
#include <linux/platform_device.h>
#include <linux/usb/role.h>
#include "core.h"
#define dwc2_ovr_gotgctl(gotgctl) \
((gotgctl) |= GOTGCTL_BVALOEN | GOTGCTL_AVALOEN | GOTGCTL_VBVALOEN | \
GOTGCTL_DBNCE_FLTR_BYPASS)
static void dwc2_ovr_init(struct dwc2_hsotg *hsotg)
{
unsigned long flags;
u32 gotgctl;
spin_lock_irqsave(&hsotg->lock, flags);
gotgctl = dwc2_readl(hsotg, GOTGCTL);
dwc2_ovr_gotgctl(gotgctl);
gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL);
if (hsotg->role_sw_default_mode == USB_DR_MODE_HOST)
gotgctl |= GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL;
else if (hsotg->role_sw_default_mode == USB_DR_MODE_PERIPHERAL)
gotgctl |= GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL;
dwc2_writel(hsotg, gotgctl, GOTGCTL);
spin_unlock_irqrestore(&hsotg->lock, flags);
dwc2_force_mode(hsotg, (hsotg->dr_mode == USB_DR_MODE_HOST) ||
(hsotg->role_sw_default_mode == USB_DR_MODE_HOST));
}
static int dwc2_ovr_avalid(struct dwc2_hsotg *hsotg, bool valid)
{
u32 gotgctl = dwc2_readl(hsotg, GOTGCTL);
/* Check if A-Session is already in the right state */
if ((valid && (gotgctl & GOTGCTL_ASESVLD)) ||
(!valid && !(gotgctl & GOTGCTL_ASESVLD)))
return -EALREADY;
/* Always enable overrides to handle the resume case */
dwc2_ovr_gotgctl(gotgctl);
gotgctl &= ~GOTGCTL_BVALOVAL;
if (valid)
gotgctl |= GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL;
else
gotgctl &= ~(GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL);
dwc2_writel(hsotg, gotgctl, GOTGCTL);
return 0;
}
static int dwc2_ovr_bvalid(struct dwc2_hsotg *hsotg, bool valid)
{
u32 gotgctl = dwc2_readl(hsotg, GOTGCTL);
/* Check if B-Session is already in the right state */
if ((valid && (gotgctl & GOTGCTL_BSESVLD)) ||
(!valid && !(gotgctl & GOTGCTL_BSESVLD)))
return -EALREADY;
/* Always enable overrides to handle the resume case */
dwc2_ovr_gotgctl(gotgctl);
gotgctl &= ~GOTGCTL_AVALOVAL;
if (valid)
gotgctl |= GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL;
else
gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL);
dwc2_writel(hsotg, gotgctl, GOTGCTL);
return 0;
}
static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
{
struct dwc2_hsotg *hsotg = usb_role_switch_get_drvdata(sw);
unsigned long flags;
int already = 0;
/* Skip session not in line with dr_mode */
if ((role == USB_ROLE_DEVICE && hsotg->dr_mode == USB_DR_MODE_HOST) ||
(role == USB_ROLE_HOST && hsotg->dr_mode == USB_DR_MODE_PERIPHERAL))
return -EINVAL;
#if IS_ENABLED(CONFIG_USB_DWC2_PERIPHERAL) || \
IS_ENABLED(CONFIG_USB_DWC2_DUAL_ROLE)
/* Skip session if core is in test mode */
if (role == USB_ROLE_NONE && hsotg->test_mode) {
dev_dbg(hsotg->dev, "Core is in test mode\n");
return -EBUSY;
}
#endif
/*
* In case of USB_DR_MODE_PERIPHERAL, clock is disabled at the end of
* the probe and enabled on udc_start.
* If role-switch set is called before the udc_start, we need to enable
* the clock to read/write GOTGCTL and GUSBCFG registers to override
* mode and sessions. It is the case if cable is plugged at boot.
*/
if (!hsotg->ll_hw_enabled && hsotg->clk) {
int ret = clk_prepare_enable(hsotg->clk);
if (ret)
return ret;
}
spin_lock_irqsave(&hsotg->lock, flags);
if (role == USB_ROLE_NONE) {
/* default operation mode when usb role is USB_ROLE_NONE */
if (hsotg->role_sw_default_mode == USB_DR_MODE_HOST)
role = USB_ROLE_HOST;
else if (hsotg->role_sw_default_mode == USB_DR_MODE_PERIPHERAL)
role = USB_ROLE_DEVICE;
}
if (role == USB_ROLE_HOST) {
already = dwc2_ovr_avalid(hsotg, true);
} else if (role == USB_ROLE_DEVICE) {
already = dwc2_ovr_bvalid(hsotg, true);
if (dwc2_is_device_enabled(hsotg)) {
/* This clear DCTL.SFTDISCON bit */
dwc2_hsotg_core_connect(hsotg);
}
} else {
if (dwc2_is_device_mode(hsotg)) {
if (!dwc2_ovr_bvalid(hsotg, false))
/* This set DCTL.SFTDISCON bit */
dwc2_hsotg_core_disconnect(hsotg);
} else {
dwc2_ovr_avalid(hsotg, false);
}
}
spin_unlock_irqrestore(&hsotg->lock, flags);
if (!already && hsotg->dr_mode == USB_DR_MODE_OTG)
/* This will raise a Connector ID Status Change Interrupt */
dwc2_force_mode(hsotg, role == USB_ROLE_HOST);
if (!hsotg->ll_hw_enabled && hsotg->clk)
clk_disable_unprepare(hsotg->clk);
dev_dbg(hsotg->dev, "%s-session valid\n",
role == USB_ROLE_NONE ? "No" :
role == USB_ROLE_HOST ? "A" : "B");
return 0;
}
int dwc2_drd_init(struct dwc2_hsotg *hsotg)
{
struct usb_role_switch_desc role_sw_desc = {0};
struct usb_role_switch *role_sw;
int ret;
if (!device_property_read_bool(hsotg->dev, "usb-role-switch"))
return 0;
hsotg->role_sw_default_mode = usb_get_role_switch_default_mode(hsotg->dev);
role_sw_desc.driver_data = hsotg;
role_sw_desc.fwnode = dev_fwnode(hsotg->dev);
role_sw_desc.set = dwc2_drd_role_sw_set;
role_sw_desc.allow_userspace_control = true;
role_sw = usb_role_switch_register(hsotg->dev, &role_sw_desc);
if (IS_ERR(role_sw)) {
ret = PTR_ERR(role_sw);
dev_err(hsotg->dev,
"failed to register role switch: %d\n", ret);
return ret;
}
hsotg->role_sw = role_sw;
/* Enable override and initialize values */
dwc2_ovr_init(hsotg);
return 0;
}
void dwc2_drd_suspend(struct dwc2_hsotg *hsotg)
{
u32 gintsts, gintmsk;
if (hsotg->role_sw && !hsotg->params.external_id_pin_ctl) {
gintmsk = dwc2_readl(hsotg, GINTMSK);
gintmsk &= ~GINTSTS_CONIDSTSCHNG;
dwc2_writel(hsotg, gintmsk, GINTMSK);
gintsts = dwc2_readl(hsotg, GINTSTS);
dwc2_writel(hsotg, gintsts | GINTSTS_CONIDSTSCHNG, GINTSTS);
}
}
void dwc2_drd_resume(struct dwc2_hsotg *hsotg)
{
u32 gintsts, gintmsk;
enum usb_role role;
if (hsotg->role_sw) {
/* get last known role (as the get ops isn't implemented by this driver) */
role = usb_role_switch_get_role(hsotg->role_sw);
if (role == USB_ROLE_NONE) {
if (hsotg->role_sw_default_mode == USB_DR_MODE_HOST)
role = USB_ROLE_HOST;
else if (hsotg->role_sw_default_mode == USB_DR_MODE_PERIPHERAL)
role = USB_ROLE_DEVICE;
}
/* restore last role that may have been lost */
if (role == USB_ROLE_HOST)
dwc2_ovr_avalid(hsotg, true);
else if (role == USB_ROLE_DEVICE)
dwc2_ovr_bvalid(hsotg, true);
dwc2_force_mode(hsotg, role == USB_ROLE_HOST);
dev_dbg(hsotg->dev, "resuming %s-session valid\n",
role == USB_ROLE_NONE ? "No" :
role == USB_ROLE_HOST ? "A" : "B");
}
if (hsotg->role_sw && !hsotg->params.external_id_pin_ctl) {
gintsts = dwc2_readl(hsotg, GINTSTS);
dwc2_writel(hsotg, gintsts | GINTSTS_CONIDSTSCHNG, GINTSTS);
gintmsk = dwc2_readl(hsotg, GINTMSK);
gintmsk |= GINTSTS_CONIDSTSCHNG;
dwc2_writel(hsotg, gintmsk, GINTMSK);
}
}
void dwc2_drd_exit(struct dwc2_hsotg *hsotg)
{
if (hsotg->role_sw)
usb_role_switch_unregister(hsotg->role_sw);
}
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