Hello,
On 2014-10-25 03:16, Paul Zimmerman wrote:
From: Marek Szyprowski [mailto:m.szyprowski@xxxxxxxxxxx]
Sent: Monday, October 20, 2014 3:46 AM
Suspend/resume code assumed that the gadget was always enabled and
connected to usb bus. This means that the actual state of the gadget
(soft-enabled/disabled or connected/disconnected) was not correctly
preserved on suspend/resume cycle. This patch fixes this issue.
Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
---
drivers/usb/dwc2/core.h | 4 +++-
drivers/usb/dwc2/gadget.c | 43 +++++++++++++++++++++++++++----------------
2 files changed, 30 insertions(+), 17 deletions(-)
diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
index bf015ab3b44c..3648b76a18b4 100644
--- a/drivers/usb/dwc2/core.h
+++ b/drivers/usb/dwc2/core.h
@@ -210,7 +210,9 @@ struct s3c_hsotg {
u8 ctrl_buff[8];
struct usb_gadget gadget;
- unsigned int setup;
+ unsigned int setup:1;
+ unsigned int connected:1;
+ unsigned int enabled:1;
unsigned long last_rst;
struct s3c_hsotg_ep *eps;
};
diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
index 0d34cfc71bfb..c6c6cf982c90 100644
--- a/drivers/usb/dwc2/gadget.c
+++ b/drivers/usb/dwc2/gadget.c
@@ -2925,6 +2925,8 @@ static int s3c_hsotg_udc_start(struct usb_gadget *gadget,
spin_lock_irqsave(&hsotg->lock, flags);
s3c_hsotg_init(hsotg);
s3c_hsotg_core_init_disconnected(hsotg);
+ hsotg->enabled = 1;
+ hsotg->connected = 0;
spin_unlock_irqrestore(&hsotg->lock, flags);
dev_info(hsotg->dev, "bound driver %s\n", driver->driver.name);
@@ -2961,6 +2963,8 @@ static int s3c_hsotg_udc_stop(struct usb_gadget *gadget,
hsotg->driver = NULL;
hsotg->gadget.speed = USB_SPEED_UNKNOWN;
+ hsotg->enabled = 0;
+ hsotg->connected = 0;
spin_unlock_irqrestore(&hsotg->lock, flags);
@@ -2999,11 +3003,14 @@ static int s3c_hsotg_pullup(struct usb_gadget *gadget, int is_on)
dev_dbg(hsotg->dev, "%s: is_on: %d\n", __func__, is_on);
spin_lock_irqsave(&hsotg->lock, flags);
+
if (is_on) {
clk_enable(hsotg->clk);
+ hsotg->connected = 1;
s3c_hsotg_core_connect(hsotg);
} else {
s3c_hsotg_core_disconnect(hsotg);
+ hsotg->connected = 0;
clk_disable(hsotg->clk);
}
@@ -3652,16 +3659,18 @@ static int s3c_hsotg_suspend(struct platform_device *pdev, pm_message_t state)
dev_info(hsotg->dev, "suspending usb gadget %s\n",
hsotg->driver->driver.name);
- spin_lock_irqsave(&hsotg->lock, flags);
- s3c_hsotg_core_disconnect(hsotg);
- s3c_hsotg_disconnect(hsotg);
- hsotg->gadget.speed = USB_SPEED_UNKNOWN;
- spin_unlock_irqrestore(&hsotg->lock, flags);
+ if (hsotg->enabled) {
Hmm. Are you sure it's safe to check ->enabled outside of the spinlock?
What happens if s3c_hsotg_udc_stop() runs right after this, before the
spinlock is taken, and disables stuff? Sure, it's a tiny window, but
still...
This code is called only in system suspend path, when userspace has been
already frozen.
udc_stop() can be called only as a result of userspace action, so it is
imho safe to
assume that the above code doesn't need additional locking.
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
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