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Date: Wed, 23 Nov 2016 13:46:17 +0100
From: Benjamin Tissoires <benjamin.tissoires@...hat.com>
To: Nick Dyer <nick@...anahar.org>
Cc: Dmitry Torokhov <dmitry.torokhov@...il.com>,
Andrew Duggan <aduggan@...aptics.com>,
Chris Healy <cphealy@...il.com>,
Henrik Rydberg <rydberg@...math.org>,
Linus Walleij <linus.walleij@...aro.org>,
Bjorn Andersson <bjorn.andersson@...aro.org>,
linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 1/2] Input: synaptics-rmi4 - add support for F34
device reflash
On Nov 23 2016 or thereabouts, Nick Dyer wrote:
> On Wed, Nov 23, 2016 at 12:20:41PM +0100, Benjamin Tissoires wrote:
> > On Nov 20 2016 or thereabouts, Nick Dyer wrote:
> > > Add support for updating firmware, triggered by a sysfs attribute.
> > >
> > > This patch has been tested on Synaptics S7300.
> > >
> > > Signed-off-by: Nick Dyer <nick@...anahar.org>
> > > Tested-by: Chris Healy <cphealy@...il.com>
> > > ---
> > > drivers/input/rmi4/Kconfig | 11 +
> > > drivers/input/rmi4/Makefile | 1 +
> > > drivers/input/rmi4/rmi_bus.c | 3 +
> > > drivers/input/rmi4/rmi_driver.c | 105 ++++++---
> > > drivers/input/rmi4/rmi_driver.h | 24 ++
> > > drivers/input/rmi4/rmi_f01.c | 6 +
> > > drivers/input/rmi4/rmi_f34.c | 481 ++++++++++++++++++++++++++++++++++++++++
> > > drivers/input/rmi4/rmi_f34.h | 68 ++++++
> > > include/linux/rmi.h | 2 +
> > > 9 files changed, 670 insertions(+), 31 deletions(-)
> > > create mode 100644 drivers/input/rmi4/rmi_f34.c
> > > create mode 100644 drivers/input/rmi4/rmi_f34.h
> > >
> > > diff --git a/drivers/input/rmi4/Kconfig b/drivers/input/rmi4/Kconfig
> > > index 8cbd362..9a24867 100644
> > > --- a/drivers/input/rmi4/Kconfig
> > > +++ b/drivers/input/rmi4/Kconfig
> > > @@ -74,6 +74,17 @@ config RMI4_F30
> > > Function 30 provides GPIO and LED support for RMI4 devices. This
> > > includes support for buttons on TouchPads and ClickPads.
> > >
> > > +config RMI4_F34
> > > + bool "RMI4 Function 34 (Device reflash)"
> > > + depends on RMI4_CORE
> > > + select FW_LOADER
> > > + help
> > > + Say Y here if you want to add support for RMI4 function 34.
> > > +
> > > + Function 34 provides support for upgrading the firmware on the RMI4
> > > + device via the firmware loader interface. This is triggered using a
> > > + sysfs attribute.
> > > +
> > > config RMI4_F54
> > > bool "RMI4 Function 54 (Analog diagnostics)"
> > > depends on RMI4_CORE
> > > diff --git a/drivers/input/rmi4/Makefile b/drivers/input/rmi4/Makefile
> > > index a6e2752..0250abf 100644
> > > --- a/drivers/input/rmi4/Makefile
> > > +++ b/drivers/input/rmi4/Makefile
> > > @@ -7,6 +7,7 @@ rmi_core-$(CONFIG_RMI4_2D_SENSOR) += rmi_2d_sensor.o
> > > rmi_core-$(CONFIG_RMI4_F11) += rmi_f11.o
> > > rmi_core-$(CONFIG_RMI4_F12) += rmi_f12.o
> > > rmi_core-$(CONFIG_RMI4_F30) += rmi_f30.o
> > > +rmi_core-$(CONFIG_RMI4_F34) += rmi_f34.o
> > > rmi_core-$(CONFIG_RMI4_F54) += rmi_f54.o
> > >
> > > # Transports
> > > diff --git a/drivers/input/rmi4/rmi_bus.c b/drivers/input/rmi4/rmi_bus.c
> > > index 84b3212..ef7a662 100644
> > > --- a/drivers/input/rmi4/rmi_bus.c
> > > +++ b/drivers/input/rmi4/rmi_bus.c
> > > @@ -315,6 +315,9 @@ static struct rmi_function_handler *fn_handlers[] = {
> > > #ifdef CONFIG_RMI4_F30
> > > &rmi_f30_handler,
> > > #endif
> > > +#ifdef CONFIG_RMI4_F34
> > > + &rmi_f34_handler,
> > > +#endif
> > > #ifdef CONFIG_RMI4_F54
> > > &rmi_f54_handler,
> > > #endif
> > > diff --git a/drivers/input/rmi4/rmi_driver.c b/drivers/input/rmi4/rmi_driver.c
> > > index 4f8d197..2b17d8c 100644
> > > --- a/drivers/input/rmi4/rmi_driver.c
> > > +++ b/drivers/input/rmi4/rmi_driver.c
> > > @@ -35,14 +35,24 @@
> > > #define RMI_DEVICE_RESET_CMD 0x01
> > > #define DEFAULT_RESET_DELAY_MS 100
> > >
> > > -static void rmi_free_function_list(struct rmi_device *rmi_dev)
> > > +void rmi_free_function_list(struct rmi_device *rmi_dev)
> > > {
> > > struct rmi_function *fn, *tmp;
> > > struct rmi_driver_data *data = dev_get_drvdata(&rmi_dev->dev);
> > >
> > > rmi_dbg(RMI_DEBUG_CORE, &rmi_dev->dev, "Freeing function list\n");
> > >
> > > + mutex_lock(&data->irq_mutex);
> >
> > Sorry for coming late in the party, but now that I am rebasing my
> > patches on top of Dmitry's branch, I realise that the mutex lock/unlock
> > operations are just wrong now.
> >
> > irq_mutex used to protect the irq_mask of struct rmi_driver_data and
> > where only used sparsely by the .config call during reset. It was also
> > used by rmi_process_interrupt_requests() in the IRQ handler, but the
> > chances of the conflict where low. Side note, this should be a spinlock
> > given that it can be called in an interrupt context.
>
> Ack
>
> > But with this patch, the mutex now serves as a barrier for IRQs. It is
> > now taken by a lot of functions that can stall a lot, and so the IRQ
> > will not be happy to be put to sleep.
> >
> > Looking at the code, I realise that we should be able to avoid the whole
> > locks by the firmware update if we simply disable/enable the interrupts
> > before attempting the firmware update (in rmi_firmware_update()).
> >
> > If you agree with the general idea, I can revert those locks and simply
> > call enable_irq/disable_irq in a following patch.
>
> I don't believe the firmware update will work without the interrupts
> being enabled - it uses a completion:
>
> http://git.kernel.org/cgit/linux/kernel/git/dtor/input.git/tree/drivers/input/rmi4/rmi_f34.c?h=synaptics-rmi4#n103
>
> I would suggest that if this is a problem, we can change the F34 to not
> use the interrupt and poll instead?
No I was simply talking about disabling/re-enabling the interrupts:
---
diff --git a/drivers/input/rmi4/rmi_f34.c b/drivers/input/rmi4/rmi_f34.c
index 03df85a..e97770e 100644
--- a/drivers/input/rmi4/rmi_f34.c
+++ b/drivers/input/rmi4/rmi_f34.c
@@ -282,6 +282,7 @@ int rmi_f34_update_firmware(struct f34_data *f34, const struct firmware *fw)
static int rmi_firmware_update(struct rmi_driver_data *data,
const struct firmware *fw)
{
+ struct rmi_device_platform_data *pdata = rmi_get_platform_data(rmi_dev);
struct device *dev = &data->rmi_dev->dev;
struct f34_data *f34;
int ret;
@@ -305,6 +306,8 @@ static int rmi_firmware_update(struct rmi_driver_data *data,
if (ret)
return ret;
+ disable_irq(pdata->irq);
+
/* Tear down functions and re-probe */
rmi_free_function_list(data->rmi_dev);
@@ -324,6 +327,8 @@ static int rmi_firmware_update(struct rmi_driver_data *data,
f34 = dev_get_drvdata(&data->f34_container->dev);
+ enable_irq(pdata->irq);
+
/* Perform firmware update */
ret = rmi_f34_update_firmware(f34, fw);
---
This way, rmi_free_function_list() and rmi_init_functions() don't need to be
protected by the mutex and you avoid the deadlock possibilities.
Cheers,
Benjamin
>
> cheers
>
> Nick
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