Re: [PATCH v6 2/3] usb: dwc2: override PHY input signals with usb role switch support

From: Amelie DELAUNAY
Date: Thu Sep 24 2020 - 08:08:41 EST

Gentle reminder.

Thanks,
Amelie

On 9/9/20 11:35 AM, Amelie DELAUNAY wrote:
This patch adds support for usb role switch to dwc2, by using overriding
control of the PHY voltage valid and ID input signals.

iddig signal (ID) can be overridden:
- when setting GUSBCFG_FORCEHOSTMODE, iddig input pin is overridden with 1;
- when setting GUSBCFG_FORCEDEVMODE, iddig input pin is overridden with 0.

avalid/bvalid/vbusvalid signals can be overridden respectively with:
- GOTGCTL_AVALOEN + GOTGCTL_AVALOVAL
- GOTGCTL_BVALOEN + GOTGCTL_BVALOVAL
- GOTGCTL_VBVALEN + GOTGCTL_VBVALOVAL

It is possible to determine valid sessions thanks to usb role switch:
- if USB_ROLE_NONE then !avalid && !bvalid && !vbusvalid
- if USB_ROLE_DEVICE then !avalid && bvalid && vbusvalid
- if USB_ROLE_HOST then avalid && !bvalid && vbusvalid

Acked-by: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>
Signed-off-by: Amelie Delaunay <amelie.delaunay@xxxxxx>
---
Changes in v5:
- Select USB_ROLE_SWITCH if USB_DWC2, and not only if USB_DWC2_DUAL_ROLE:
drd.c is built whatever DWC2 mode (DUAL, HOST, PERIPHERAL) as it is used also
to detect attach/detach (so a-valid/b-valid sessions).
No changes in v5.
Changes in v4:
- Simplify call to dwc2_force_mode in drd.c
- Add error_drd label in probe error path in platform.c
Changes in v3:
- Fix build issue reported by kernel test robot in drd.c
Changes in v2:
- Fix build issue reported by kernel test robot
- Move call to dwc2_force_mode outside spinlock context
- Add dwc2_drd_exit call in probe error path
---
drivers/usb/dwc2/Kconfig | 1 +
drivers/usb/dwc2/Makefile | 2 +-
drivers/usb/dwc2/core.h | 9 ++
drivers/usb/dwc2/drd.c | 180 ++++++++++++++++++++++++++++++++++++
drivers/usb/dwc2/gadget.c | 2 +-
drivers/usb/dwc2/platform.c | 20 +++-
6 files changed, 210 insertions(+), 4 deletions(-)
create mode 100644 drivers/usb/dwc2/drd.c

diff --git a/drivers/usb/dwc2/Kconfig b/drivers/usb/dwc2/Kconfig
index 16e1aa304edc..c131719367ec 100644
--- a/drivers/usb/dwc2/Kconfig
+++ b/drivers/usb/dwc2/Kconfig
@@ -5,6 +5,7 @@ config USB_DWC2
depends on HAS_DMA
depends on USB || USB_GADGET
depends on HAS_IOMEM
+ select USB_ROLE_SWITCH
help
Say Y here if your system has a Dual Role Hi-Speed USB
controller based on the DesignWare HSOTG IP Core.
diff --git a/drivers/usb/dwc2/Makefile b/drivers/usb/dwc2/Makefile
index 440320cc20a4..2bcd6945df46 100644
--- a/drivers/usb/dwc2/Makefile
+++ b/drivers/usb/dwc2/Makefile
@@ -3,7 +3,7 @@ ccflags-$(CONFIG_USB_DWC2_DEBUG) += -DDEBUG
ccflags-$(CONFIG_USB_DWC2_VERBOSE) += -DVERBOSE_DEBUG
obj-$(CONFIG_USB_DWC2) += dwc2.o
-dwc2-y := core.o core_intr.o platform.o
+dwc2-y := core.o core_intr.o platform.o drd.o
dwc2-y += params.o
ifneq ($(filter y,$(CONFIG_USB_DWC2_HOST) $(CONFIG_USB_DWC2_DUAL_ROLE)),)
diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
index 9deff0400a92..7161344c6522 100644
--- a/drivers/usb/dwc2/core.h
+++ b/drivers/usb/dwc2/core.h
@@ -860,6 +860,7 @@ struct dwc2_hregs_backup {
* - USB_DR_MODE_PERIPHERAL
* - USB_DR_MODE_HOST
* - USB_DR_MODE_OTG
+ * @role_sw: usb_role_switch handle
* @hcd_enabled: Host mode sub-driver initialization indicator.
* @gadget_enabled: Peripheral mode sub-driver initialization indicator.
* @ll_hw_enabled: Status of low-level hardware resources.
@@ -1054,6 +1055,7 @@ struct dwc2_hsotg {
struct dwc2_core_params params;
enum usb_otg_state op_state;
enum usb_dr_mode dr_mode;
+ struct usb_role_switch *role_sw;
unsigned int hcd_enabled:1;
unsigned int gadget_enabled:1;
unsigned int ll_hw_enabled:1;
@@ -1376,6 +1378,11 @@ static inline int dwc2_is_device_mode(struct dwc2_hsotg *hsotg)
return (dwc2_readl(hsotg, GINTSTS) & GINTSTS_CURMODE_HOST) == 0;
}
+int dwc2_drd_init(struct dwc2_hsotg *hsotg);
+void dwc2_drd_suspend(struct dwc2_hsotg *hsotg);
+void dwc2_drd_resume(struct dwc2_hsotg *hsotg);
+void dwc2_drd_exit(struct dwc2_hsotg *hsotg);
+
/*
* Dump core registers and SPRAM
*/
@@ -1392,6 +1399,7 @@ int dwc2_hsotg_resume(struct dwc2_hsotg *dwc2);
int dwc2_gadget_init(struct dwc2_hsotg *hsotg);
void dwc2_hsotg_core_init_disconnected(struct dwc2_hsotg *dwc2,
bool reset);
+void dwc2_hsotg_core_disconnect(struct dwc2_hsotg *hsotg);
void dwc2_hsotg_core_connect(struct dwc2_hsotg *hsotg);
void dwc2_hsotg_disconnect(struct dwc2_hsotg *dwc2);
int dwc2_hsotg_set_test_mode(struct dwc2_hsotg *hsotg, int testmode);
@@ -1417,6 +1425,7 @@ static inline int dwc2_gadget_init(struct dwc2_hsotg *hsotg)
{ return 0; }
static inline void dwc2_hsotg_core_init_disconnected(struct dwc2_hsotg *dwc2,
bool reset) {}
+static inline void dwc2_hsotg_core_disconnect(struct dwc2_hsotg *hsotg) {}
static inline void dwc2_hsotg_core_connect(struct dwc2_hsotg *hsotg) {}
static inline void dwc2_hsotg_disconnect(struct dwc2_hsotg *dwc2) {}
static inline int dwc2_hsotg_set_test_mode(struct dwc2_hsotg *hsotg,
diff --git a/drivers/usb/dwc2/drd.c b/drivers/usb/dwc2/drd.c
new file mode 100644
index 000000000000..2d4176f5788e
--- /dev/null
+++ b/drivers/usb/dwc2/drd.c
@@ -0,0 +1,180 @@
+// 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@xxxxxx>
+ */
+
+#include <linux/iopoll.h>
+#include <linux/platform_device.h>
+#include <linux/usb/role.h>
+#include "core.h"
+
+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);
+ gotgctl |= GOTGCTL_BVALOEN | GOTGCTL_AVALOEN | GOTGCTL_VBVALOEN;
+ gotgctl |= GOTGCTL_DBNCE_FLTR_BYPASS;
+ gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL);
+ dwc2_writel(hsotg, gotgctl, GOTGCTL);
+
+ dwc2_force_mode(hsotg, false);
+
+ spin_unlock_irqrestore(&hsotg->lock, flags);
+}
+
+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;
+
+ 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;
+
+ 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
+
+ spin_lock_irqsave(&hsotg->lock, flags);
+
+ if (role == USB_ROLE_HOST) {
+ already = dwc2_ovr_avalid(hsotg, true);
+ } else if (role == USB_ROLE_DEVICE) {
+ already = dwc2_ovr_bvalid(hsotg, true);
+ /* 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);
+
+ 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;
+
+ 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;
+
+ 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);
+}
diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
index 5b9d23991c99..16c5f976f141 100644
--- a/drivers/usb/dwc2/gadget.c
+++ b/drivers/usb/dwc2/gadget.c
@@ -3530,7 +3530,7 @@ void dwc2_hsotg_core_init_disconnected(struct dwc2_hsotg *hsotg,
dwc2_readl(hsotg, DOEPCTL0));
}
-static void dwc2_hsotg_core_disconnect(struct dwc2_hsotg *hsotg)
+void dwc2_hsotg_core_disconnect(struct dwc2_hsotg *hsotg)
{
/* set the soft-disconnect bit */
dwc2_set_bit(hsotg, DCTL, DCTL_SFTDISCON);
diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
index b28e90e0b685..238004050557 100644
--- a/drivers/usb/dwc2/platform.c
+++ b/drivers/usb/dwc2/platform.c
@@ -314,6 +314,8 @@ static int dwc2_driver_remove(struct platform_device *dev)
if (hsotg->gadget_enabled)
dwc2_hsotg_remove(hsotg);
+ dwc2_drd_exit(hsotg);
+
if (hsotg->params.activate_stm_id_vb_detection)
regulator_disable(hsotg->usb33d);
@@ -533,10 +535,17 @@ static int dwc2_driver_probe(struct platform_device *dev)
dwc2_writel(hsotg, ggpio, GGPIO);
}
+ retval = dwc2_drd_init(hsotg);
+ if (retval) {
+ if (retval != -EPROBE_DEFER)
+ dev_err(hsotg->dev, "failed to initialize dual-role\n");
+ goto error_init;
+ }
+
if (hsotg->dr_mode != USB_DR_MODE_HOST) {
retval = dwc2_gadget_init(hsotg);
if (retval)
- goto error_init;
+ goto error_drd;
hsotg->gadget_enabled = 1;
}
@@ -562,7 +571,7 @@ static int dwc2_driver_probe(struct platform_device *dev)
if (retval) {
if (hsotg->gadget_enabled)
dwc2_hsotg_remove(hsotg);
- goto error_init;
+ goto error_drd;
}
hsotg->hcd_enabled = 1;
}
@@ -594,6 +603,9 @@ static int dwc2_driver_probe(struct platform_device *dev)
dwc2_debugfs_exit(hsotg);
if (hsotg->hcd_enabled)
dwc2_hcd_remove(hsotg);
+error_drd:
+ dwc2_drd_exit(hsotg);
+
error_init:
if (hsotg->params.activate_stm_id_vb_detection)
regulator_disable(hsotg->usb33d);
@@ -612,6 +624,8 @@ static int __maybe_unused dwc2_suspend(struct device *dev)
if (is_device_mode)
dwc2_hsotg_suspend(dwc2);
+ dwc2_drd_suspend(dwc2);
+
if (dwc2->params.activate_stm_id_vb_detection) {
unsigned long flags;
u32 ggpio, gotgctl;
@@ -692,6 +706,8 @@ static int __maybe_unused dwc2_resume(struct device *dev)
/* Need to restore FORCEDEVMODE/FORCEHOSTMODE */
dwc2_force_dr_mode(dwc2);
+ dwc2_drd_resume(dwc2);
+
if (dwc2_is_device_mode(dwc2))
ret = dwc2_hsotg_resume(dwc2);