[PATCH 0/4] usb: musb: support for suspend and resume

[PATCH 0/4] usb: musb: support for suspend and resume

[Daniel Mack]

I've been working on some patches that allow suspending and resuming
the musb-dsps platform. This was tested for host mode only.

With these patches applied, I can successfully bring an AM335x board
to suspend with a USB media connected, and access it again after
resume. Note that this currently only works with CONFIG_MUSB_PIO_ONLY
set. The cppi41 driver needs some more love to make this work. I'll
work on that next.

Thanks,
Daniel


Daniel Mack (4):
  usb: musb: move port reset to worker
  usb: musb: call musb_port_suspend from musb_bus_suspend
  usb: musb: conditionally restore and resume the context on resume
  usb: musb: dsps: add support for suspend and resume

 drivers/usb/musb/musb_core.c    | 24 +++++++++++++++++-
 drivers/usb/musb/musb_core.h    |  3 +++
 drivers/usb/musb/musb_dsps.c    | 54 +++++++++++++++++++++++++++++++++++++++++
 drivers/usb/musb/musb_host.c    |  2 ++
 drivers/usb/musb/musb_host.h    |  4 +++
 drivers/usb/musb/musb_virthub.c | 15 +++++++-----
 include/linux/usb/musb.h        |  1 +
 7 files changed, 96 insertions(+), 7 deletions(-)

-- 
1.8.3.1

[PATCH 1/4] usb: musb: move port reset to worker

[Daniel Mack]

musb_port_reset() sleeps, so we can't call it from atomic context. It
is, however, called from places inside musb_hub_control() while
&musb->lock is held, which leads to a "scheduling while atomic" warning.

Fix this by moving the logic into a worker, and call it where the
function was previously called directly.

Signed-off-by: Daniel Mack <zonque@gmail.com>
---
 drivers/usb/musb/musb_core.c    |  7 +++++++
 drivers/usb/musb/musb_core.h    |  3 +++
 drivers/usb/musb/musb_host.h    |  2 ++
 drivers/usb/musb/musb_virthub.c | 13 ++++++++-----
 4 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
index 18e877f..2b9f4b4 100644
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -1699,6 +1699,12 @@ static void musb_irq_work(struct work_struct *data)
 	}
 }
 
+static void musb_port_reset_work(struct work_struct *data)
+{
+	struct musb *musb = container_of(data, struct musb, port_reset_work);
+	musb_port_reset(musb);
+}
+
 /* --------------------------------------------------------------------------
  * Init support
  */
@@ -1857,6 +1863,7 @@ musb_init_controller(struct device *dev, int nIrq, void __iomem *ctrl)
 
 	/* Init IRQ workqueue before request_irq */
 	INIT_WORK(&musb->irq_work, musb_irq_work);
+	INIT_WORK(&musb->port_reset_work, musb_port_reset_work);
 
 	/* attach to the IRQ */
 	if (request_irq(nIrq, musb->isr, 0, dev_name(dev), musb)) {
diff --git a/drivers/usb/musb/musb_core.h b/drivers/usb/musb/musb_core.h
index 65f3917..9529512 100644
--- a/drivers/usb/musb/musb_core.h
+++ b/drivers/usb/musb/musb_core.h
@@ -294,6 +294,9 @@ struct musb {
 
 	irqreturn_t		(*isr)(int, void *);
 	struct work_struct	irq_work;
+	struct work_struct	port_reset_work;
+	bool			port_reset_state;
+
 	u16			hwvers;
 
 	u16			intrrxe;
diff --git a/drivers/usb/musb/musb_host.h b/drivers/usb/musb/musb_host.h
index 960d735..843f48e 100644
--- a/drivers/usb/musb/musb_host.h
+++ b/drivers/usb/musb/musb_host.h
@@ -92,6 +92,7 @@ extern void musb_host_rx(struct musb *, u8);
 extern void musb_root_disconnect(struct musb *musb);
 extern void musb_host_resume_root_hub(struct musb *musb);
 extern void musb_host_poke_root_hub(struct musb *musb);
+extern void musb_port_reset(struct musb *musb);
 #else
 static inline struct musb *hcd_to_musb(struct usb_hcd *hcd)
 {
@@ -121,6 +122,7 @@ static inline void musb_root_disconnect(struct musb *musb)	{}
 static inline void musb_host_resume_root_hub(struct musb *musb)	{}
 static inline void musb_host_poll_rh_status(struct musb *musb)	{}
 static inline void musb_host_poke_root_hub(struct musb *musb)	{}
+static inline void musb_port_reset(struct musb *musb)		{}
 #endif
 
 struct usb_hcd;
diff --git a/drivers/usb/musb/musb_virthub.c b/drivers/usb/musb/musb_virthub.c
index a523950..30b43a1 100644
--- a/drivers/usb/musb/musb_virthub.c
+++ b/drivers/usb/musb/musb_virthub.c
@@ -155,7 +155,7 @@ static void musb_port_suspend(struct musb *musb, bool do_suspend)
 	}
 }
 
-static void musb_port_reset(struct musb *musb, bool do_reset)
+void musb_port_reset(struct musb *musb)
 {
 	u8		power;
 	void __iomem	*mbase = musb->mregs;
@@ -173,7 +173,7 @@ static void musb_port_reset(struct musb *musb, bool do_reset)
 	 * the appropriate amount of time has passed
 	 */
 	power = musb_readb(mbase, MUSB_POWER);
-	if (do_reset) {
+	if (musb->port_reset_state) {
 
 		/*
 		 * If RESUME is set, we must make sure it stays minimum 20 ms.
@@ -356,8 +356,10 @@ int musb_hub_control(
 
 		/* finish RESET signaling? */
 		if ((musb->port1_status & USB_PORT_STAT_RESET)
-				&& time_after_eq(jiffies, musb->rh_timer))
-			musb_port_reset(musb, false);
+				&& time_after_eq(jiffies, musb->rh_timer)) {
+			musb->port_reset_state = false;
+			schedule_work(&musb->port_reset_work);
+		}
 
 		/* finish RESUME signaling? */
 		if ((musb->port1_status & MUSB_PORT_STAT_RESUME)
@@ -412,7 +414,8 @@ int musb_hub_control(
 				musb_start(musb);
 			break;
 		case USB_PORT_FEAT_RESET:
-			musb_port_reset(musb, true);
+			musb->port_reset_state = true;
+			schedule_work(&musb->port_reset_work);
 			break;
 		case USB_PORT_FEAT_SUSPEND:
 			musb_port_suspend(musb, true);
-- 
1.8.3.1

[PATCH 2/4] usb: musb: call musb_port_suspend from musb_bus_suspend

[Daniel Mack]

Make musb_port_suspend() externally available, and call it when to host
goes into suspend. This allows the core to go into suspend while a
device is connected.

Signed-off-by: Daniel Mack <zonque-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 drivers/usb/musb/musb_host.c    | 2 ++
 drivers/usb/musb/musb_host.h    | 2 ++
 drivers/usb/musb/musb_virthub.c | 2 +-
 3 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
index 9a2b8c8..2b60596 100644
--- a/drivers/usb/musb/musb_host.c
+++ b/drivers/usb/musb/musb_host.c
@@ -2433,6 +2433,8 @@ static int musb_bus_suspend(struct usb_hcd *hcd)
 	struct musb	*musb = hcd_to_musb(hcd);
 	u8		devctl;
 
+	musb_port_suspend(musb, true);
+
 	if (!is_host_active(musb))
 		return 0;
 
diff --git a/drivers/usb/musb/musb_host.h b/drivers/usb/musb/musb_host.h
index 843f48e..dcffea7 100644
--- a/drivers/usb/musb/musb_host.h
+++ b/drivers/usb/musb/musb_host.h
@@ -93,6 +93,7 @@ extern void musb_root_disconnect(struct musb *musb);
 extern void musb_host_resume_root_hub(struct musb *musb);
 extern void musb_host_poke_root_hub(struct musb *musb);
 extern void musb_port_reset(struct musb *musb);
+extern void musb_port_suspend(struct musb *musb, bool do_suspend);
 #else
 static inline struct musb *hcd_to_musb(struct usb_hcd *hcd)
 {
@@ -123,6 +124,7 @@ static inline void musb_host_resume_root_hub(struct musb *musb)	{}
 static inline void musb_host_poll_rh_status(struct musb *musb)	{}
 static inline void musb_host_poke_root_hub(struct musb *musb)	{}
 static inline void musb_port_reset(struct musb *musb)		{}
+static inline void musb_port_suspend(struct musb *musb, bool do_suspend) {}
 #endif
 
 struct usb_hcd;
diff --git a/drivers/usb/musb/musb_virthub.c b/drivers/usb/musb/musb_virthub.c
index 30b43a1..9f3a0f3 100644
--- a/drivers/usb/musb/musb_virthub.c
+++ b/drivers/usb/musb/musb_virthub.c
@@ -90,7 +90,7 @@ static void musb_start(struct musb *musb)
 	musb_writeb(regs, MUSB_DEVCTL, devctl);
 }
 
-static void musb_port_suspend(struct musb *musb, bool do_suspend)
+void musb_port_suspend(struct musb *musb, bool do_suspend)
 {
 	struct usb_otg	*otg = musb->xceiv->otg;
 	u8		power;
-- 
1.8.3.1

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[PATCH 3/4] usb: musb: conditionally restore and resume the context on resume

[Daniel Mack]

It appears not all platforms featuring a musb core need to save the musb
core registers at suspend time and restore them on resume.

The dsps platform does, however. So add a bit in struct
musb_hdrc_platform_data to let platforms specify their need of such
action being taken.

Signed-off-by: Daniel Mack <zonque@gmail.com>
---
 drivers/usb/musb/musb_core.c | 17 ++++++++++++++++-
 include/linux/usb/musb.h     |  1 +
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
index 2b9f4b4..f17604e 100644
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -2152,6 +2152,7 @@ static int musb_suspend(struct device *dev)
 {
 	struct musb	*musb = dev_to_musb(dev);
 	unsigned long	flags;
+	struct musb_hdrc_platform_data *plat = dev_get_platdata(dev);
 
 	spin_lock_irqsave(&musb->lock, flags);
 
@@ -2165,16 +2166,30 @@ static int musb_suspend(struct device *dev)
 		 */
 	}
 
+	if (plat->restore_after_suspend)
+		musb_save_context(musb);
+
 	spin_unlock_irqrestore(&musb->lock, flags);
 	return 0;
 }
 
 static int musb_resume_noirq(struct device *dev)
 {
-	/* for static cmos like DaVinci, register values were preserved
+	struct musb	*musb = dev_to_musb(dev);
+	struct musb_hdrc_platform_data *plat = dev_get_platdata(dev);
+
+	/*
+	 * For static cmos like DaVinci, register values were preserved
 	 * unless for some reason the whole soc powered down or the USB
 	 * module got reset through the PSC (vs just being disabled).
+	 *
+	 * The plaform data tells us about the necessity of saving and
+	 * restoring the context across a suspend cycle.
 	 */
+
+	if (plat->restore_after_suspend)
+		musb_restore_context(musb);
+
 	return 0;
 }
 
diff --git a/include/linux/usb/musb.h b/include/linux/usb/musb.h
index 053c268..296be6c 100644
--- a/include/linux/usb/musb.h
+++ b/include/linux/usb/musb.h
@@ -100,6 +100,7 @@ struct musb_hdrc_platform_data {
 	u8		mode;
 
 	u8		has_mailbox:1;
+	u8		restore_after_suspend:1;
 
 	/* for clk_get() */
 	const char	*clock;
-- 
1.8.3.1

[PATCH 4/4] usb: musb: dsps: add support for suspend and resume

[Daniel Mack]

The dsps platform needs to save save some registers at suspend time and
restore them after resume. This patch adds a struct for these registers,
and also lets the musb core know that the core registers need to be
saved as well.

Signed-off-by: Daniel Mack <zonque@gmail.com>
---
 drivers/usb/musb/musb_dsps.c | 54 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/drivers/usb/musb/musb_dsps.c b/drivers/usb/musb/musb_dsps.c
index 4047cbb..c93c365 100644
--- a/drivers/usb/musb/musb_dsps.c
+++ b/drivers/usb/musb/musb_dsps.c
@@ -110,6 +110,17 @@ struct dsps_musb_wrapper {
 	u8		poll_seconds;
 };
 
+/*
+ * register shadow for suspend
+ */
+struct dsps_context {
+	u32 control;
+	u32 epintr;
+	u32 coreintr;
+	u32 phy_utmi;
+	u32 mode;
+};
+
 /**
  * DSPS glue structure.
  */
@@ -119,6 +130,8 @@ struct dsps_glue {
 	const struct dsps_musb_wrapper *wrp; /* wrapper register offsets */
 	struct timer_list timer;	/* otg_workaround timer */
 	unsigned long last_timer;    /* last timer data for each instance */
+
+	struct dsps_context context;
 };
 
 /**
@@ -502,6 +515,7 @@ static int dsps_create_musb_pdev(struct dsps_glue *glue,
 	}
 	pdata.config = config;
 	pdata.platform_ops = &dsps_ops;
+	pdata.restore_after_suspend = 1;
 
 	config->num_eps = get_int_prop(dn, "mentor,num-eps");
 	config->ram_bits = get_int_prop(dn, "mentor,ram-bits");
@@ -623,11 +637,51 @@ static const struct of_device_id musb_dsps_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, musb_dsps_of_match);
 
+#ifdef CONFIG_PM
+static int dsps_suspend(struct device *dev)
+{
+	struct dsps_glue *glue = dev_get_drvdata(dev);
+	const struct dsps_musb_wrapper *wrp = glue->wrp;
+	struct musb *musb = platform_get_drvdata(glue->musb);
+	void __iomem *mbase = musb->ctrl_base;
+
+	glue->context.control = dsps_readl(mbase, wrp->control);
+	glue->context.epintr = dsps_readl(mbase, wrp->epintr_set);
+	glue->context.coreintr = dsps_readl(mbase, wrp->coreintr_set);
+	glue->context.phy_utmi = dsps_readl(mbase, wrp->phy_utmi);
+	glue->context.mode = dsps_readl(mbase, wrp->mode);
+
+	return 0;
+}
+
+static int dsps_resume(struct device *dev)
+{
+	struct dsps_glue *glue = dev_get_drvdata(dev);
+	const struct dsps_musb_wrapper *wrp = glue->wrp;
+	struct musb *musb = platform_get_drvdata(glue->musb);
+	void __iomem *mbase = musb->ctrl_base;
+
+	dsps_writel(mbase, wrp->control, glue->context.control);
+	dsps_writel(mbase, wrp->epintr_set, glue->context.epintr);
+	dsps_writel(mbase, wrp->coreintr_set, glue->context.coreintr);
+	dsps_writel(mbase, wrp->phy_utmi, glue->context.phy_utmi);
+	dsps_writel(mbase, wrp->mode, glue->context.mode);
+
+	musb->port_reset_state = false;
+	schedule_work(&musb->port_reset_work);
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(dsps_pm_ops, dsps_suspend, dsps_resume);
+
 static struct platform_driver dsps_usbss_driver = {
 	.probe		= dsps_probe,
 	.remove         = dsps_remove,
 	.driver         = {
 		.name   = "musb-dsps",
+		.pm	= &dsps_pm_ops,
 		.of_match_table	= of_match_ptr(musb_dsps_of_match),
 	},
 };
-- 
1.8.3.1

Re: [PATCH 0/4] usb: musb: support for suspend and resume

[Daniel Mack]

On 26.09.2013 15:08, Daniel Mack wrote:
> I've been working on some patches that allow suspending and resuming
> the musb-dsps platform. This was tested for host mode only.
> 
> With these patches applied, I can successfully bring an AM335x board
> to suspend with a USB media connected, and access it again after
> resume. Note that this currently only works with CONFIG_MUSB_PIO_ONLY
> set. The cppi41 driver needs some more love to make this work. I'll
> work on that next.

As this series hasn't been applied yet, please consider it outdated. I
have some more patches coming and will include them when publishing a
new round of patches.


Thanks,
Daniel