* [PATCHv4 1/3] USB: gadget: atmel_usba_udc: Fixed vbus_prev initial state
2015-01-20 21:23 [PATCHv4 0/3] USB: gadget: atmel_usba_udc: Start clocks on rising edge of the Vbus signal, stop clocks on falling edge of the Vbus signal Sylvain Rochet
@ 2015-01-20 21:23 ` Sylvain Rochet
2015-01-20 21:23 ` [PATCHv4 2/3] USB: gadget: atmel_usba_udc: Enable Vbus signal IRQ in UDC start instead of UDC probe Sylvain Rochet
2015-01-20 21:23 ` [PATCHv4 3/3] USB: gadget: atmel_usba_udc: Start clocks on rising edge of the Vbus signal, stop clocks on falling edge of the Vbus signal Sylvain Rochet
2 siblings, 0 replies; 6+ messages in thread
From: Sylvain Rochet @ 2015-01-20 21:23 UTC (permalink / raw)
To: linux-arm-kernel
If vbus gpio is high at init, we should set vbus_prev to true
accordingly to the current vbus state. Without that, we skip the first
vbus interrupt because the saved vbus state is not consistent.
Signed-off-by: Sylvain Rochet <sylvain.rochet@finsecur.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Fixes: 914a3f3b3754 ("USB: add atmel_usba_udc driver")
Cc: <stable@vger.kernel.org> #2.6.24+
---
drivers/usb/gadget/udc/atmel_usba_udc.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/usb/gadget/udc/atmel_usba_udc.c b/drivers/usb/gadget/udc/atmel_usba_udc.c
index ce88237..e207d75 100644
--- a/drivers/usb/gadget/udc/atmel_usba_udc.c
+++ b/drivers/usb/gadget/udc/atmel_usba_udc.c
@@ -1791,6 +1791,8 @@ static int atmel_usba_start(struct usb_gadget *gadget,
toggle_bias(1);
usba_writel(udc, CTRL, USBA_ENABLE_MASK);
usba_writel(udc, INT_ENB, USBA_END_OF_RESET);
+
+ udc->vbus_prev = 1;
}
spin_unlock_irqrestore(&udc->lock, flags);
--
2.1.4
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCHv4 2/3] USB: gadget: atmel_usba_udc: Enable Vbus signal IRQ in UDC start instead of UDC probe
2015-01-20 21:23 [PATCHv4 0/3] USB: gadget: atmel_usba_udc: Start clocks on rising edge of the Vbus signal, stop clocks on falling edge of the Vbus signal Sylvain Rochet
2015-01-20 21:23 ` [PATCHv4 1/3] USB: gadget: atmel_usba_udc: Fixed vbus_prev initial state Sylvain Rochet
@ 2015-01-20 21:23 ` Sylvain Rochet
2015-01-21 9:20 ` Boris Brezillon
2015-01-20 21:23 ` [PATCHv4 3/3] USB: gadget: atmel_usba_udc: Start clocks on rising edge of the Vbus signal, stop clocks on falling edge of the Vbus signal Sylvain Rochet
2 siblings, 1 reply; 6+ messages in thread
From: Sylvain Rochet @ 2015-01-20 21:23 UTC (permalink / raw)
To: linux-arm-kernel
Vbus IRQ handler needs a started UDC driver to work because it uses
udc->driver, which is set by the UDC start handler. The previous way
chosen was to return from interrupt if udc->driver is NULL using a
spinlock.
This patch now request the Vbus signal IRQ in UDC start instead of UDC
probe and release the IRQ in UDC stop before udc->driver is set back to
NULL. This way we don't need the check about udc->driver in interruption
handler, therefore we don't need the spinlock as well anymore.
This was chosen against using set_irq_flags() to request a not auto
enabled IRQ (IRQF_NOAUTOEN flag) because set_irq_flags() can't change
just one flag, therefore it must be called with all flags, without
respecting what the AIC previously did. Naively copying IRQ flags
currently set by the AIC looked like error-prone if defaults flags
change at some point in the future.
Signed-off-by: Sylvain Rochet <sylvain.rochet@finsecur.com>
Suggested-by: Boris Brezillon <boris.brezillon@free-electrons.com>
---
drivers/usb/gadget/udc/atmel_usba_udc.c | 64 ++++++++++++++++-----------------
1 file changed, 32 insertions(+), 32 deletions(-)
diff --git a/drivers/usb/gadget/udc/atmel_usba_udc.c b/drivers/usb/gadget/udc/atmel_usba_udc.c
index e207d75..546da63 100644
--- a/drivers/usb/gadget/udc/atmel_usba_udc.c
+++ b/drivers/usb/gadget/udc/atmel_usba_udc.c
@@ -1729,10 +1729,6 @@ static irqreturn_t usba_vbus_irq(int irq, void *devid)
spin_lock(&udc->lock);
- /* May happen if Vbus pin toggles during probe() */
- if (!udc->driver)
- goto out;
-
vbus = vbus_is_present(udc);
if (vbus != udc->vbus_prev) {
if (vbus) {
@@ -1753,7 +1749,6 @@ static irqreturn_t usba_vbus_irq(int irq, void *devid)
udc->vbus_prev = vbus;
}
-out:
spin_unlock(&udc->lock);
return IRQ_HANDLED;
@@ -1767,23 +1762,27 @@ static int atmel_usba_start(struct usb_gadget *gadget,
unsigned long flags;
spin_lock_irqsave(&udc->lock, flags);
-
udc->devstatus = 1 << USB_DEVICE_SELF_POWERED;
udc->driver = driver;
spin_unlock_irqrestore(&udc->lock, flags);
ret = clk_prepare_enable(udc->pclk);
if (ret)
- return ret;
+ goto err_pclk;
ret = clk_prepare_enable(udc->hclk);
- if (ret) {
- clk_disable_unprepare(udc->pclk);
- return ret;
- }
+ if (ret)
+ goto err_hclk;
udc->vbus_prev = 0;
- if (gpio_is_valid(udc->vbus_pin))
- enable_irq(gpio_to_irq(udc->vbus_pin));
+ if (gpio_is_valid(udc->vbus_pin)) {
+ ret = request_irq(gpio_to_irq(udc->vbus_pin),
+ usba_vbus_irq, 0,
+ "atmel_usba_udc", udc);
+ if (ret) {
+ udc->vbus_pin = -ENODEV;
+ goto err;
+ }
+ }
/* If Vbus is present, enable the controller and wait for reset */
spin_lock_irqsave(&udc->lock, flags);
@@ -1797,6 +1796,17 @@ static int atmel_usba_start(struct usb_gadget *gadget,
spin_unlock_irqrestore(&udc->lock, flags);
return 0;
+
+err:
+ clk_disable_unprepare(udc->hclk);
+err_hclk:
+ clk_disable_unprepare(udc->pclk);
+err_pclk:
+ spin_lock_irqsave(&udc->lock, flags);
+ udc->devstatus &= ~(1 << USB_DEVICE_SELF_POWERED);
+ udc->driver = NULL;
+ spin_unlock_irqrestore(&udc->lock, flags);
+ return ret;
}
static int atmel_usba_stop(struct usb_gadget *gadget)
@@ -1805,7 +1815,7 @@ static int atmel_usba_stop(struct usb_gadget *gadget)
unsigned long flags;
if (gpio_is_valid(udc->vbus_pin))
- disable_irq(gpio_to_irq(udc->vbus_pin));
+ free_irq(gpio_to_irq(udc->vbus_pin), udc);
spin_lock_irqsave(&udc->lock, flags);
udc->gadget.speed = USB_SPEED_UNKNOWN;
@@ -2047,24 +2057,14 @@ static int usba_udc_probe(struct platform_device *pdev)
}
udc->irq = irq;
- if (gpio_is_valid(udc->vbus_pin)) {
- if (!devm_gpio_request(&pdev->dev, udc->vbus_pin, "atmel_usba_udc")) {
- ret = devm_request_irq(&pdev->dev,
- gpio_to_irq(udc->vbus_pin),
- usba_vbus_irq, 0,
- "atmel_usba_udc", udc);
- if (ret) {
- udc->vbus_pin = -ENODEV;
- dev_warn(&udc->pdev->dev,
- "failed to request vbus irq; "
- "assuming always on\n");
- } else {
- disable_irq(gpio_to_irq(udc->vbus_pin));
- }
- } else {
- /* gpio_request fail so use -EINVAL for gpio_is_valid */
- udc->vbus_pin = -EINVAL;
- }
+ if (gpio_is_valid(udc->vbus_pin)
+ && devm_gpio_request(&pdev->dev, udc->vbus_pin,
+ "atmel_usba_udc")) {
+ /* gpio_request fail so use -EINVAL for gpio_is_valid */
+ udc->vbus_pin = -EINVAL;
+ dev_warn(&udc->pdev->dev,
+ "failed to request vbus gpio; "
+ "assuming always on\n");
}
ret = usb_add_gadget_udc(&pdev->dev, &udc->gadget);
--
2.1.4
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCHv4 2/3] USB: gadget: atmel_usba_udc: Enable Vbus signal IRQ in UDC start instead of UDC probe
2015-01-20 21:23 ` [PATCHv4 2/3] USB: gadget: atmel_usba_udc: Enable Vbus signal IRQ in UDC start instead of UDC probe Sylvain Rochet
@ 2015-01-21 9:20 ` Boris Brezillon
2015-01-21 13:18 ` Sylvain Rochet
0 siblings, 1 reply; 6+ messages in thread
From: Boris Brezillon @ 2015-01-21 9:20 UTC (permalink / raw)
To: linux-arm-kernel
Hi Sylvain,
On Tue, 20 Jan 2015 22:23:29 +0100
Sylvain Rochet <sylvain.rochet@finsecur.com> wrote:
> Vbus IRQ handler needs a started UDC driver to work because it uses
> udc->driver, which is set by the UDC start handler. The previous way
> chosen was to return from interrupt if udc->driver is NULL using a
> spinlock.
>
> This patch now request the Vbus signal IRQ in UDC start instead of UDC
> probe and release the IRQ in UDC stop before udc->driver is set back to
> NULL. This way we don't need the check about udc->driver in interruption
> handler, therefore we don't need the spinlock as well anymore.
>
> This was chosen against using set_irq_flags() to request a not auto
> enabled IRQ (IRQF_NOAUTOEN flag) because set_irq_flags() can't change
> just one flag, therefore it must be called with all flags, without
> respecting what the AIC previously did. Naively copying IRQ flags
> currently set by the AIC looked like error-prone if defaults flags
> change at some point in the future.
>
> Signed-off-by: Sylvain Rochet <sylvain.rochet@finsecur.com>
> Suggested-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> ---
> drivers/usb/gadget/udc/atmel_usba_udc.c | 64 ++++++++++++++++-----------------
> 1 file changed, 32 insertions(+), 32 deletions(-)
>
> diff --git a/drivers/usb/gadget/udc/atmel_usba_udc.c b/drivers/usb/gadget/udc/atmel_usba_udc.c
> index e207d75..546da63 100644
> --- a/drivers/usb/gadget/udc/atmel_usba_udc.c
> +++ b/drivers/usb/gadget/udc/atmel_usba_udc.c
> @@ -1729,10 +1729,6 @@ static irqreturn_t usba_vbus_irq(int irq, void *devid)
>
> spin_lock(&udc->lock);
>
> - /* May happen if Vbus pin toggles during probe() */
> - if (!udc->driver)
> - goto out;
> -
> vbus = vbus_is_present(udc);
> if (vbus != udc->vbus_prev) {
> if (vbus) {
> @@ -1753,7 +1749,6 @@ static irqreturn_t usba_vbus_irq(int irq, void *devid)
> udc->vbus_prev = vbus;
> }
>
> -out:
> spin_unlock(&udc->lock);
>
> return IRQ_HANDLED;
> @@ -1767,23 +1762,27 @@ static int atmel_usba_start(struct usb_gadget *gadget,
> unsigned long flags;
>
> spin_lock_irqsave(&udc->lock, flags);
> -
> udc->devstatus = 1 << USB_DEVICE_SELF_POWERED;
> udc->driver = driver;
> spin_unlock_irqrestore(&udc->lock, flags);
>
> ret = clk_prepare_enable(udc->pclk);
> if (ret)
> - return ret;
> + goto err_pclk;
> ret = clk_prepare_enable(udc->hclk);
> - if (ret) {
> - clk_disable_unprepare(udc->pclk);
> - return ret;
> - }
> + if (ret)
> + goto err_hclk;
>
> udc->vbus_prev = 0;
> - if (gpio_is_valid(udc->vbus_pin))
> - enable_irq(gpio_to_irq(udc->vbus_pin));
> + if (gpio_is_valid(udc->vbus_pin)) {
> + ret = request_irq(gpio_to_irq(udc->vbus_pin),
> + usba_vbus_irq, 0,
> + "atmel_usba_udc", udc);
> + if (ret) {
> + udc->vbus_pin = -ENODEV;
I guess you're trying to protect against free_irq by changing the
vbus_pin value (making it an invalid gpio id), but I think you should
leave it unchanged for two reasons:
1) If the request_irq call temporary fails (an ENOMEM for example) then
you should be able to retry later, and modifying the vbus_pin value
will prevent that.
2) atmel_usba_stop will never be called if the atmel_usba_start failed,
so there's no need to protect against this free_irq.
Best Regards,
Boris
--
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCHv4 2/3] USB: gadget: atmel_usba_udc: Enable Vbus signal IRQ in UDC start instead of UDC probe
2015-01-21 9:20 ` Boris Brezillon
@ 2015-01-21 13:18 ` Sylvain Rochet
0 siblings, 0 replies; 6+ messages in thread
From: Sylvain Rochet @ 2015-01-21 13:18 UTC (permalink / raw)
To: linux-arm-kernel
Hi Boris,
On Wed, Jan 21, 2015 at 10:20:16AM +0100, Boris Brezillon wrote:
> >
> > udc->vbus_prev = 0;
> > - if (gpio_is_valid(udc->vbus_pin))
> > - enable_irq(gpio_to_irq(udc->vbus_pin));
> > + if (gpio_is_valid(udc->vbus_pin)) {
> > + ret = request_irq(gpio_to_irq(udc->vbus_pin),
> > + usba_vbus_irq, 0,
> > + "atmel_usba_udc", udc);
> > + if (ret) {
> > + udc->vbus_pin = -ENODEV;
>
> I guess you're trying to protect against free_irq by changing the
> vbus_pin value (making it an invalid gpio id), but I think you should
> leave it unchanged for two reasons:
> 1) If the request_irq call temporary fails (an ENOMEM for example) then
> you should be able to retry later, and modifying the vbus_pin value
> will prevent that.
> 2) atmel_usba_stop will never be called if the atmel_usba_start failed,
> so there's no need to protect against this free_irq.
Indeed.
By the way, I just discovered irq_set_status_flags(irq, IRQ_NOAUTOEN); ?
so I am going for a v5 and the previous part is not relevant anymore.
Sylvain
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCHv4 3/3] USB: gadget: atmel_usba_udc: Start clocks on rising edge of the Vbus signal, stop clocks on falling edge of the Vbus signal
2015-01-20 21:23 [PATCHv4 0/3] USB: gadget: atmel_usba_udc: Start clocks on rising edge of the Vbus signal, stop clocks on falling edge of the Vbus signal Sylvain Rochet
2015-01-20 21:23 ` [PATCHv4 1/3] USB: gadget: atmel_usba_udc: Fixed vbus_prev initial state Sylvain Rochet
2015-01-20 21:23 ` [PATCHv4 2/3] USB: gadget: atmel_usba_udc: Enable Vbus signal IRQ in UDC start instead of UDC probe Sylvain Rochet
@ 2015-01-20 21:23 ` Sylvain Rochet
2 siblings, 0 replies; 6+ messages in thread
From: Sylvain Rochet @ 2015-01-20 21:23 UTC (permalink / raw)
To: linux-arm-kernel
If USB PLL is not necessary for other USB drivers (e.g. OHCI and EHCI)
it will reduce power consumption by switching off the USB PLL if no USB
Host is currently connected to this USB Device.
We are using Vbus GPIO signal to detect Host presence. If Vbus signal is
not available then the device stays continuously clocked.
Note this driver does not support suspend/resume yet, it may stay
clocked if USB Host is still connected when suspending. For what I need,
forbidding suspend from userland if we are still attached to an USB host
is fine, but we might as well add suspend/resume to this driver in the
future.
Signed-off-by: Sylvain Rochet <sylvain.rochet@finsecur.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
---
drivers/usb/gadget/udc/atmel_usba_udc.c | 86 ++++++++++++++++++++++++---------
drivers/usb/gadget/udc/atmel_usba_udc.h | 4 ++
2 files changed, 66 insertions(+), 24 deletions(-)
diff --git a/drivers/usb/gadget/udc/atmel_usba_udc.c b/drivers/usb/gadget/udc/atmel_usba_udc.c
index 546da63..e05b16c 100644
--- a/drivers/usb/gadget/udc/atmel_usba_udc.c
+++ b/drivers/usb/gadget/udc/atmel_usba_udc.c
@@ -315,6 +315,37 @@ static inline void usba_cleanup_debugfs(struct usba_udc *udc)
}
#endif
+static int start_clock(struct usba_udc *udc)
+{
+ int ret;
+
+ if (udc->clocked)
+ return 0;
+
+ ret = clk_prepare_enable(udc->pclk);
+ if (ret)
+ return ret;
+ ret = clk_prepare_enable(udc->hclk);
+ if (ret) {
+ clk_disable_unprepare(udc->pclk);
+ return ret;
+ }
+
+ udc->clocked = true;
+ return 0;
+}
+
+static void stop_clock(struct usba_udc *udc)
+{
+ if (!udc->clocked)
+ return;
+
+ clk_disable_unprepare(udc->hclk);
+ clk_disable_unprepare(udc->pclk);
+
+ udc->clocked = false;
+}
+
static int vbus_is_present(struct usba_udc *udc)
{
if (gpio_is_valid(udc->vbus_pin))
@@ -1719,37 +1750,48 @@ static irqreturn_t usba_udc_irq(int irq, void *devid)
return IRQ_HANDLED;
}
-static irqreturn_t usba_vbus_irq(int irq, void *devid)
+static irqreturn_t usba_vbus_irq_thread(int irq, void *devid)
{
struct usba_udc *udc = devid;
int vbus;
+ int ret;
+ unsigned long flags;
/* debounce */
udelay(10);
- spin_lock(&udc->lock);
+ mutex_lock(&udc->vbus_mutex);
vbus = vbus_is_present(udc);
if (vbus != udc->vbus_prev) {
if (vbus) {
+ ret = start_clock(udc);
+ if (ret)
+ goto out;
+
+ spin_lock_irqsave(&udc->lock, flags);
toggle_bias(1);
usba_writel(udc, CTRL, USBA_ENABLE_MASK);
usba_writel(udc, INT_ENB, USBA_END_OF_RESET);
+ spin_unlock_irqrestore(&udc->lock, flags);
} else {
+ spin_lock_irqsave(&udc->lock, flags);
udc->gadget.speed = USB_SPEED_UNKNOWN;
reset_all_endpoints(udc);
toggle_bias(0);
usba_writel(udc, CTRL, USBA_DISABLE_MASK);
- if (udc->driver->disconnect) {
- spin_unlock(&udc->lock);
+ spin_unlock_irqrestore(&udc->lock, flags);
+
+ stop_clock(udc);
+
+ if (udc->driver->disconnect)
udc->driver->disconnect(&udc->gadget);
- spin_lock(&udc->lock);
- }
}
udc->vbus_prev = vbus;
}
- spin_unlock(&udc->lock);
+out:
+ mutex_unlock(&udc->vbus_mutex);
return IRQ_HANDLED;
}
@@ -1766,17 +1808,12 @@ static int atmel_usba_start(struct usb_gadget *gadget,
udc->driver = driver;
spin_unlock_irqrestore(&udc->lock, flags);
- ret = clk_prepare_enable(udc->pclk);
- if (ret)
- goto err_pclk;
- ret = clk_prepare_enable(udc->hclk);
- if (ret)
- goto err_hclk;
+ mutex_lock(&udc->vbus_mutex);
udc->vbus_prev = 0;
if (gpio_is_valid(udc->vbus_pin)) {
- ret = request_irq(gpio_to_irq(udc->vbus_pin),
- usba_vbus_irq, 0,
+ ret = request_threaded_irq(gpio_to_irq(udc->vbus_pin), NULL,
+ usba_vbus_irq_thread, IRQF_ONESHOT,
"atmel_usba_udc", udc);
if (ret) {
udc->vbus_pin = -ENODEV;
@@ -1785,23 +1822,24 @@ static int atmel_usba_start(struct usb_gadget *gadget,
}
/* If Vbus is present, enable the controller and wait for reset */
- spin_lock_irqsave(&udc->lock, flags);
if (vbus_is_present(udc) && udc->vbus_prev == 0) {
+ ret = start_clock(udc);
+ if (ret)
+ goto err;
+
+ spin_lock_irqsave(&udc->lock, flags);
toggle_bias(1);
usba_writel(udc, CTRL, USBA_ENABLE_MASK);
usba_writel(udc, INT_ENB, USBA_END_OF_RESET);
+ spin_unlock_irqrestore(&udc->lock, flags);
udc->vbus_prev = 1;
}
- spin_unlock_irqrestore(&udc->lock, flags);
+ mutex_unlock(&udc->vbus_mutex);
return 0;
-
err:
- clk_disable_unprepare(udc->hclk);
-err_hclk:
- clk_disable_unprepare(udc->pclk);
-err_pclk:
+ mutex_unlock(&udc->vbus_mutex);
spin_lock_irqsave(&udc->lock, flags);
udc->devstatus &= ~(1 << USB_DEVICE_SELF_POWERED);
udc->driver = NULL;
@@ -1826,8 +1864,7 @@ static int atmel_usba_stop(struct usb_gadget *gadget)
toggle_bias(0);
usba_writel(udc, CTRL, USBA_DISABLE_MASK);
- clk_disable_unprepare(udc->hclk);
- clk_disable_unprepare(udc->pclk);
+ stop_clock(udc);
udc->driver = NULL;
@@ -2007,6 +2044,7 @@ static int usba_udc_probe(struct platform_device *pdev)
return PTR_ERR(hclk);
spin_lock_init(&udc->lock);
+ mutex_init(&udc->vbus_mutex);
udc->pdev = pdev;
udc->pclk = pclk;
udc->hclk = hclk;
diff --git a/drivers/usb/gadget/udc/atmel_usba_udc.h b/drivers/usb/gadget/udc/atmel_usba_udc.h
index a70706e..3ceed76 100644
--- a/drivers/usb/gadget/udc/atmel_usba_udc.h
+++ b/drivers/usb/gadget/udc/atmel_usba_udc.h
@@ -308,6 +308,9 @@ struct usba_udc {
/* Protect hw registers from concurrent modifications */
spinlock_t lock;
+ /* Mutex to prevent concurrent start or stop */
+ struct mutex vbus_mutex;
+
void __iomem *regs;
void __iomem *fifo;
@@ -321,6 +324,7 @@ struct usba_udc {
struct clk *pclk;
struct clk *hclk;
struct usba_ep *usba_ep;
+ bool clocked;
u16 devstatus;
--
2.1.4
^ permalink raw reply related [flat|nested] 6+ messages in thread