[PATCH v5 1/3] gpiolib: Add init_valid_mask exported function

[PATCH v5 1/3] gpiolib: Add init_valid_mask exported function

[Ricardo Ribalda Delgado]

Add a function that allows initializing the valid_mask from
gpiochip_add_data.

This prevents race conditions during gpiochip initialization.

If the function is not exported, then the old behaviour is respected,
this is, set all gpios as valid.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
---
 drivers/gpio/gpiolib.c      | 16 ++++++++++++++--
 include/linux/gpio/driver.h |  7 ++++++-
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index e8f8a1999393..907019b67a58 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -359,7 +359,7 @@ static unsigned long *gpiochip_allocate_mask(struct gpio_chip *chip)
 	return p;
 }
 
-static int gpiochip_init_valid_mask(struct gpio_chip *gpiochip)
+static int gpiochip_alloc_valid_mask(struct gpio_chip *gpiochip)
 {
 #ifdef CONFIG_OF_GPIO
 	int size;
@@ -380,6 +380,14 @@ static int gpiochip_init_valid_mask(struct gpio_chip *gpiochip)
 	return 0;
 }
 
+static int gpiochip_init_valid_mask(struct gpio_chip *gpiochip)
+{
+	if (gpiochip->init_valid_mask)
+		return gpiochip->init_valid_mask(gpiochip);
+
+	return 0;
+}
+
 static void gpiochip_free_valid_mask(struct gpio_chip *gpiochip)
 {
 	kfree(gpiochip->valid_mask);
@@ -1367,7 +1375,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
 	if (status)
 		goto err_remove_from_list;
 
-	status = gpiochip_init_valid_mask(chip);
+	status = gpiochip_alloc_valid_mask(chip);
 	if (status)
 		goto err_remove_irqchip_mask;
 
@@ -1379,6 +1387,10 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
 	if (status)
 		goto err_remove_chip;
 
+	status = gpiochip_init_valid_mask(chip);
+	if (status)
+		goto err_remove_chip;
+
 	acpi_gpiochip_add(chip);
 
 	machine_gpiochip_add(chip);
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index 0ea328e71ec9..df09749269ff 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -256,6 +256,9 @@ struct gpio_chip {
 
 	void			(*dbg_show)(struct seq_file *s,
 						struct gpio_chip *chip);
+
+	int			(*init_valid_mask)(struct gpio_chip *chip);
+
 	int			base;
 	u16			ngpio;
 	const char		*const *names;
@@ -294,7 +297,9 @@ struct gpio_chip {
 	/**
 	 * @need_valid_mask:
 	 *
-	 * If set core allocates @valid_mask with all bits set to one.
+	 * If set core allocates @valid_mask with all its values initialized
+	 * with init_valid_mask() or set to one if init_valid_mask() is not
+	 * defined
 	 */
 	bool need_valid_mask;
 
-- 
2.19.0

[PATCH v5 2/3] pinctrl: msm: Use init_valid_mask exported function

[Ricardo Ribalda Delgado]

The current code produces XPU violation if get_direction is called just
after the initialization.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
---
 drivers/pinctrl/qcom/pinctrl-msm.c | 79 ++++++++++++++----------------
 1 file changed, 37 insertions(+), 42 deletions(-)

diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c
index 5d72ffad32c2..ce1ade47ea37 100644
--- a/drivers/pinctrl/qcom/pinctrl-msm.c
+++ b/drivers/pinctrl/qcom/pinctrl-msm.c
@@ -566,6 +566,42 @@ static void msm_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 #define msm_gpio_dbg_show NULL
 #endif
 
+static int msm_gpio_init_valid_mask(struct gpio_chip *chip)
+{
+	struct msm_pinctrl *pctrl = gpiochip_get_data(chip);
+	int ret;
+	unsigned int len, i;
+	unsigned int max_gpios = pctrl->soc->ngpios;
+	u16 *tmp;
+
+	/* The number of GPIOs in the ACPI tables */
+	len = ret = device_property_read_u16_array(pctrl->dev, "gpios", NULL,
+						   0);
+	if (ret < 0)
+		return 0;
+
+	if (ret > max_gpios)
+		return -EINVAL;
+
+	tmp = kmalloc_array(len, sizeof(*tmp), GFP_KERNEL);
+	if (!tmp)
+		return -ENOMEM;
+
+	ret = device_property_read_u16_array(pctrl->dev, "gpios", tmp, len);
+	if (ret < 0) {
+		dev_err(pctrl->dev, "could not read list of GPIOs\n");
+		goto out;
+	}
+
+	bitmap_zero(chip->valid_mask, max_gpios);
+	for (i = 0; i < len; i++)
+		set_bit(tmp[i], chip->valid_mask);
+
+out:
+	kfree(tmp);
+	return ret;
+}
+
 static const struct gpio_chip msm_gpio_template = {
 	.direction_input  = msm_gpio_direction_input,
 	.direction_output = msm_gpio_direction_output,
@@ -575,6 +611,7 @@ static const struct gpio_chip msm_gpio_template = {
 	.request          = gpiochip_generic_request,
 	.free             = gpiochip_generic_free,
 	.dbg_show         = msm_gpio_dbg_show,
+	.init_valid_mask  = msm_gpio_init_valid_mask,
 };
 
 /* For dual-edge interrupts in software, since some hardware has no
@@ -855,41 +892,6 @@ static void msm_gpio_irq_handler(struct irq_desc *desc)
 	chained_irq_exit(chip, desc);
 }
 
-static int msm_gpio_init_valid_mask(struct gpio_chip *chip,
-				    struct msm_pinctrl *pctrl)
-{
-	int ret;
-	unsigned int len, i;
-	unsigned int max_gpios = pctrl->soc->ngpios;
-	u16 *tmp;
-
-	/* The number of GPIOs in the ACPI tables */
-	len = ret = device_property_read_u16_array(pctrl->dev, "gpios", NULL, 0);
-	if (ret < 0)
-		return 0;
-
-	if (ret > max_gpios)
-		return -EINVAL;
-
-	tmp = kmalloc_array(len, sizeof(*tmp), GFP_KERNEL);
-	if (!tmp)
-		return -ENOMEM;
-
-	ret = device_property_read_u16_array(pctrl->dev, "gpios", tmp, len);
-	if (ret < 0) {
-		dev_err(pctrl->dev, "could not read list of GPIOs\n");
-		goto out;
-	}
-
-	bitmap_zero(chip->valid_mask, max_gpios);
-	for (i = 0; i < len; i++)
-		set_bit(tmp[i], chip->valid_mask);
-
-out:
-	kfree(tmp);
-	return ret;
-}
-
 static bool msm_gpio_needs_valid_mask(struct msm_pinctrl *pctrl)
 {
 	return device_property_read_u16_array(pctrl->dev, "gpios", NULL, 0) > 0;
@@ -926,13 +928,6 @@ static int msm_gpio_init(struct msm_pinctrl *pctrl)
 		return ret;
 	}
 
-	ret = msm_gpio_init_valid_mask(chip, pctrl);
-	if (ret) {
-		dev_err(pctrl->dev, "Failed to setup irq valid bits\n");
-		gpiochip_remove(&pctrl->chip);
-		return ret;
-	}
-
 	/*
 	 * For DeviceTree-supported systems, the gpio core checks the
 	 * pinctrl's device node for the "gpio-ranges" property.
-- 
2.19.0

[PATCH v5 3/3] gpiolib: Show correct direction from the beginning

[Ricardo Ribalda Delgado]

Current code assumes that the direction is input if direction_input
function is set.
This might not be the case on GPIOs with programmable direction.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
---
 drivers/gpio/gpiolib.c | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 907019b67a58..e016b22658ff 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1349,20 +1349,6 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
 
 	spin_unlock_irqrestore(&gpio_lock, flags);
 
-	for (i = 0; i < chip->ngpio; i++) {
-		struct gpio_desc *desc = &gdev->descs[i];
-
-		desc->gdev = gdev;
-
-		/* REVISIT: most hardware initializes GPIOs as inputs (often
-		 * with pullups enabled) so power usage is minimized. Linux
-		 * code should set the gpio direction first thing; but until
-		 * it does, and in case chip->get_direction is not set, we may
-		 * expose the wrong direction in sysfs.
-		 */
-		desc->flags = !chip->direction_input ? (1 << FLAG_IS_OUT) : 0;
-	}
-
 #ifdef CONFIG_PINCTRL
 	INIT_LIST_HEAD(&gdev->pin_ranges);
 #endif
@@ -1391,6 +1377,19 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
 	if (status)
 		goto err_remove_chip;
 
+	for (i = 0; i < chip->ngpio; i++) {
+		struct gpio_desc *desc = &gdev->descs[i];
+
+		desc->gdev = gdev;
+
+		if (chip->get_direction && gpiochip_line_is_valid(chip, i))
+			desc->flags = !chip->get_direction(chip, i) ?
+					(1 << FLAG_IS_OUT) : 0;
+		else
+			desc->flags = !chip->direction_input ?
+					(1 << FLAG_IS_OUT) : 0;
+	}
+
 	acpi_gpiochip_add(chip);
 
 	machine_gpiochip_add(chip);
-- 
2.19.0

Re: [PATCH v5 3/3] gpiolib: Show correct direction from the beginning

[Jeffrey Hugo]

On 10/5/2018 12:53 AM, Ricardo Ribalda Delgado wrote:
> Current code assumes that the direction is input if direction_input
> function is set.
> This might not be the case on GPIOs with programmable direction.
> 
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
> ---
>   drivers/gpio/gpiolib.c | 27 +++++++++++++--------------
>   1 file changed, 13 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index 907019b67a58..e016b22658ff 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -1349,20 +1349,6 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
>   
>   	spin_unlock_irqrestore(&gpio_lock, flags);
>   
> -	for (i = 0; i < chip->ngpio; i++) {
> -		struct gpio_desc *desc = &gdev->descs[i];
> -
> -		desc->gdev = gdev;
> -
> -		/* REVISIT: most hardware initializes GPIOs as inputs (often
> -		 * with pullups enabled) so power usage is minimized. Linux
> -		 * code should set the gpio direction first thing; but until
> -		 * it does, and in case chip->get_direction is not set, we may
> -		 * expose the wrong direction in sysfs.
> -		 */
> -		desc->flags = !chip->direction_input ? (1 << FLAG_IS_OUT) : 0;
> -	}
> -
>   #ifdef CONFIG_PINCTRL
>   	INIT_LIST_HEAD(&gdev->pin_ranges);
>   #endif
> @@ -1391,6 +1377,19 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
>   	if (status)
>   		goto err_remove_chip;
>   
> +	for (i = 0; i < chip->ngpio; i++) {
> +		struct gpio_desc *desc = &gdev->descs[i];
> +
> +		desc->gdev = gdev;
> +
> +		if (chip->get_direction && gpiochip_line_is_valid(chip, i))
> +			desc->flags = !chip->get_direction(chip, i) ?
> +					(1 << FLAG_IS_OUT) : 0;
> +		else
> +			desc->flags = !chip->direction_input ?
> +					(1 << FLAG_IS_OUT) : 0;
> +	}
> +
>   	acpi_gpiochip_add(chip);
>   
>   	machine_gpiochip_add(chip);
> 

We have a successful boot this time.

Timur I see:
ubuntu@ubuntu:~$ dmesg | grep gpio
[    7.388887] gpiochip_find_base: found new base at 362
[    7.433186] gpio gpiochip0: (QCOM8002:00): added GPIO chardev (254:0)
[    7.433218] gpiochip_setup_dev: registered GPIOs 362 to 511 on 
device: gpiochip0 (QCOM8002:00)
[    7.433222] gpio gpiochip0: (QCOM8002:00): created GPIO range 0->149 
==> QCOM8002:00 PIN 0->149

Looks like the driver is initing just fine to me.  Is setting up the 
jumpers and running gpio-test warranted?

-- 
Jeffrey Hugo
Qualcomm Datacenter Technologies as an affiliate of Qualcomm 
Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.

Re: [PATCH v5 3/3] gpiolib: Show correct direction from the beginning

[Timur Tabi]

On 10/05/2018 11:17 AM, Jeffrey Hugo wrote:>
> Looks like the driver is initing just fine to me.  Is setting up the
> jumpers and running gpio-test warranted?

Well, that test only makes sure that input/output is actually working
on the hardware level, but it also makes sure that the GPIOs are
numbered correctly.

If you want, just put a printk(... offset) in msm_gpio_get() and read
from a GPIO that you know you have access to, and make sure the
'offset' is correct.

Then try reading from a GPIO that you don't have access to, and make
sure you get a failure before msm_gpio_get() is called.

Re: [PATCH v5 3/3] gpiolib: Show correct direction from the beginning

[Timur Tabi]

On Fri, Oct 5, 2018 at 11:54 AM Timur Tabi <timur@kernel.org> wrote:
> If you want, just put a printk(... offset) in msm_gpio_get() and read
> from a GPIO that you know you have access to, and make sure the
> 'offset' is correct.
>
> Then try reading from a GPIO that you don't have access to, and make
> sure you get a failure before msm_gpio_get() is called.

Just FYI, if you use sysfs to write to the GPIO, based on the kernel
log you pasted, GPIO 362 in sysfs is actually pin 0 in the TLMM.

If you use gpio-test, it uses gpiolib which figures this all out for
you.  There should still be the gpio-test wiki page I wrote that tells
you how to use it.

Re: [PATCH v5 2/3] pinctrl: msm: Use init_valid_mask exported function

[Timur Tabi]

On 10/5/18 1:52 AM, Ricardo Ribalda Delgado wrote:
> The current code produces XPU violation if get_direction is called just
> after the initialization.
> 
> Signed-off-by: Ricardo Ribalda Delgado<ricardo.ribalda@gmail.com>

I'm not the maintainer of pinctrl-msm, but this looks okay to me.

Acked-by: Timur Tabi <timur@kernel.org>

Re: [PATCH v5 3/3] gpiolib: Show correct direction from the beginning

[Jeffrey Hugo]

On 10/5/2018 10:54 AM, Timur Tabi wrote:
> On 10/05/2018 11:17 AM, Jeffrey Hugo wrote:>
>> Looks like the driver is initing just fine to me.  Is setting up the
>> jumpers and running gpio-test warranted?
> 
> Well, that test only makes sure that input/output is actually working
> on the hardware level, but it also makes sure that the GPIOs are
> numbered correctly.
> 
> If you want, just put a printk(... offset) in msm_gpio_get() and read
> from a GPIO that you know you have access to, and make sure the
> 'offset' is correct.
> 
> Then try reading from a GPIO that you don't have access to, and make
> sure you get a failure before msm_gpio_get() is called.
> 

Done.

For the series:

Tested-by: Jeffrey Hugo <jhugo@codeaurora.org>

-- 
Jeffrey Hugo
Qualcomm Datacenter Technologies as an affiliate of Qualcomm 
Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.

Re: [PATCH v5 1/3] gpiolib: Add init_valid_mask exported function

[Linus Walleij]

On Fri, Oct 5, 2018 at 8:53 AM Ricardo Ribalda Delgado
<ricardo.ribalda@gmail.com> wrote:

> Add a function that allows initializing the valid_mask from
> gpiochip_add_data.
>
> This prevents race conditions during gpiochip initialization.
>
> If the function is not exported, then the old behaviour is respected,
> this is, set all gpios as valid.
>
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>

Patch applied,

thanks a lot for your hard work on this!

Yours,
Linus Walleij

Re: [PATCH v5 2/3] pinctrl: msm: Use init_valid_mask exported function

[Linus Walleij]

On Fri, Oct 5, 2018 at 8:53 AM Ricardo Ribalda Delgado
<ricardo.ribalda@gmail.com> wrote:

> The current code produces XPU violation if get_direction is called just
> after the initialization.
>
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>

Patch applied with Timur's ACK.
The code makes perfect sense.
I hope Bjorn has no reservations, if he does I guess I have to
just back it out.

Yours,
Linus Walleij

Re: [PATCH v5 3/3] gpiolib: Show correct direction from the beginning

[Linus Walleij]

On Fri, Oct 5, 2018 at 8:53 AM Ricardo Ribalda Delgado
<ricardo.ribalda@gmail.com> wrote:

> Current code assumes that the direction is input if direction_input
> function is set.
> This might not be the case on GPIOs with programmable direction.
>
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>

Patch applied with the collected ACKs.

Thanks for working so hard on fixing this up.

Yours,
Linus Walleij

Re: [PATCH v5 3/3] gpiolib: Show correct direction from the beginning

[Vignesh R]

Hi,

On Friday 05 October 2018 12:23 PM, Ricardo Ribalda Delgado wrote:
> Current code assumes that the direction is input if direction_input
> function is set.
> This might not be the case on GPIOs with programmable direction.
> 
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
> Tested-by: Jeffrey Hugo <jhugo@codeaurora.org>

This patch causes oops on TI's AM335x-ICEv2 board on next-20181011:

[    0.563797] OMAP GPIO hardware version 0.1
[    0.577589] Unable to handle kernel NULL pointer dereference at virtual address 000002b8
[    0.586127] pgd = (ptrval)
[    0.588934] [000002b8] *pgd=00000000
[    0.592732] Internal error: Oops: 5 [#1] SMP ARM
[    0.597499] Modules linked in:
[    0.600668] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.19.0-rc7-next-20181011 #70
[    0.608466] Hardware name: Generic AM33XX (Flattened Device Tree)
[    0.614770] PC is at gpiod_hog+0x30/0x154
[    0.618913] LR is at of_gpiochip_add+0x2fc/0x4e4
[    0.623671] pc : [<c055213c>]    lr : [<c0553ff0>]    psr: 60000013
[    0.630130] sp : ce09bba0  ip : cdf08095  fp : 00000000
[    0.635516] r10: c0bfcf24  r9 : 00000000  r8 : 00000007
[    0.640902] r7 : cdf08088  r6 : 00000000  r5 : 00000000  r4 : ce191e40
[    0.647630] r3 : 00000000  r2 : 00000000  r1 : cdf08088  r0 : ce191e40
[    0.654361] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
[    0.661718] Control: 10c5387d  Table: 80004019  DAC: 00000051
[    0.667642] Process swapper/0 (pid: 1, stack limit = 0x(ptrval))
[...]
[    0.973593] [<c055213c>] (gpiod_hog) from [<c0553ff0>] (of_gpiochip_add+0x2fc/0x4e4)
[    0.981588] [<c0553ff0>] (of_gpiochip_add) from [<c05528a0>] (gpiochip_add_data_with_key+
0x5a0/0x990)
[    0.991102] [<c05528a0>] (gpiochip_add_data_with_key) from [<c0556d8c>] (omap_gpio_probe+
0x37c/0x75c)
[    1.000613] [<c0556d8c>] (omap_gpio_probe) from [<c06049c0>] (platform_drv_probe+0x48/0x9
8)
[    1.009237] [<c06049c0>] (platform_drv_probe) from [<c0602a04>] (really_probe+0x220/0x2d4
)
[    1.017764] [<c0602a04>] (really_probe) from [<c0602c18>] (driver_probe_device+0x5c/0x164
)
[    1.026293] [<c0602c18>] (driver_probe_device) from [<c0600d44>] (bus_for_each_drv+0x54/0
xb8)
[    1.035090] [<c0600d44>] (bus_for_each_drv) from [<c060276c>] (__device_attach+0xcc/0x13c
)
[    1.043615] [<c060276c>] (__device_attach) from [<c0601b88>] (bus_probe_device+0x88/0x90)
[    1.052051] [<c0601b88>] (bus_probe_device) from [<c05fea18>] (device_add+0x3d8/0x608)
[    1.060223] [<c05fea18>] (device_add) from [<c07343b8>] (of_platform_device_create_pdata+
0x8c/0xc0)
[    1.069552] [<c07343b8>] (of_platform_device_create_pdata) from [<c07345c4>] (of_platform
_bus_create+0x190/0x228)
[    1.080134] [<c07345c4>] (of_platform_bus_create) from [<c0734610>] (of_platform_bus_crea
te+0x1dc/0x228)
[    1.089909] [<c0734610>] (of_platform_bus_create) from [<c073478c>] (of_platform_populate
+0x5c/0xac)
[    1.099333] [<c073478c>] (of_platform_populate) from [<c0d12614>] (pdata_quirks_init+0x6c
/0x90)
[    1.108306] [<c0d12614>] (pdata_quirks_init) from [<c0d12144>] (omap_generic_init+0xc/0x1
8)
[    1.116933] [<c0d12144>] (omap_generic_init) from [<c0d03eb0>] (customize_machine+0x1c/0x
30)
[    1.125645] [<c0d03eb0>] (customize_machine) from [<c01030e4>] (do_one_initcall+0x80/0x31
0)
[    1.134265] [<c01030e4>] (do_one_initcall) from [<c0d01244>] (kernel_init_freeable+0x3c4/
0x4ac)
[    1.143238] [<c0d01244>] (kernel_init_freeable) from [<c0900f28>] (kernel_init+0x8/0x114)
[    1.151673] [<c0900f28>] (kernel_init) from [<c01010b4>] (ret_from_fork+0x14/0x20)
[    1.159475] Exception stack(0xce09bfb0 to 0xce09bff8)
[    1.164686] bfa0:                                     00000000 00000000 00000000 00000000
[    1.173119] bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[    1.181551] bfe0: 00000000 00000000 00000000 00000000 00000013 00000000
[    1.188378] Code: 0a000002 e3530000 01a09003 159392b4 (e59352b8) 
[    1.194766] ---[ end trace d5c17cd400f50a22 ]---
[    1.199606] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
[    1.199606] 
[    1.209052] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000
00b
[    1.209052]  ]---
[    3.172292] random: fast init done

Full log: https://pastebin.ubuntu.com/p/jG8nN6CTBP/

Reverting this patch from linux-next allows to boot to prompt.

Regards
Vignesh

> ---
>  drivers/gpio/gpiolib.c | 27 +++++++++++++--------------
>  1 file changed, 13 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index 907019b67a58..e016b22658ff 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -1349,20 +1349,6 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
>  
>  	spin_unlock_irqrestore(&gpio_lock, flags);
>  
> -	for (i = 0; i < chip->ngpio; i++) {
> -		struct gpio_desc *desc = &gdev->descs[i];
> -
> -		desc->gdev = gdev;
> -
> -		/* REVISIT: most hardware initializes GPIOs as inputs (often
> -		 * with pullups enabled) so power usage is minimized. Linux
> -		 * code should set the gpio direction first thing; but until
> -		 * it does, and in case chip->get_direction is not set, we may
> -		 * expose the wrong direction in sysfs.
> -		 */
> -		desc->flags = !chip->direction_input ? (1 << FLAG_IS_OUT) : 0;
> -	}
> -
>  #ifdef CONFIG_PINCTRL
>  	INIT_LIST_HEAD(&gdev->pin_ranges);
>  #endif
> @@ -1391,6 +1377,19 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
>  	if (status)
>  		goto err_remove_chip;
>  
> +	for (i = 0; i < chip->ngpio; i++) {
> +		struct gpio_desc *desc = &gdev->descs[i];
> +
> +		desc->gdev = gdev;
> +
> +		if (chip->get_direction && gpiochip_line_is_valid(chip, i))
> +			desc->flags = !chip->get_direction(chip, i) ?
> +					(1 << FLAG_IS_OUT) : 0;
> +		else
> +			desc->flags = !chip->direction_input ?
> +					(1 << FLAG_IS_OUT) : 0;
> +	}
> +
>  	acpi_gpiochip_add(chip);
>  
>  	machine_gpiochip_add(chip);
> 

Re: [PATCH v5 3/3] gpiolib: Show correct direction from the beginning

[Ricardo Ribalda Delgado]

Hi Vignesh

Ups, it does not look too good :S . Can you check if this change fixes it:

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index e016b22658ff..bcd0ef49ce97 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1349,6 +1349,9 @@ int gpiochip_add_data_with_key(struct gpio_chip
*chip, void *data,

        spin_unlock_irqrestore(&gpio_lock, flags);

+       for (i = 0; i < chip->ngpio; i++)
+               gdev->descs[i].gdev = gdev;
+
 #ifdef CONFIG_PINCTRL
        INIT_LIST_HEAD(&gdev->pin_ranges);
 #endif
@@ -1380,8 +1383,6 @@ int gpiochip_add_data_with_key(struct gpio_chip
*chip, void *data,
        for (i = 0; i < chip->ngpio; i++) {
                struct gpio_desc *desc = &gdev->descs[i];

-               desc->gdev = gdev;
-
                if (chip->get_direction && gpiochip_line_is_valid(chip, i))
                        desc->flags = !chip->get_direction(chip, i) ?
                                        (1 << FLAG_IS_OUT) : 0;


Thanks!
On Thu, Oct 11, 2018 at 2:18 PM Vignesh R <vigneshr@ti.com> wrote:
>
> Hi,
>
> On Friday 05 October 2018 12:23 PM, Ricardo Ribalda Delgado wrote:
> > Current code assumes that the direction is input if direction_input
> > function is set.
> > This might not be the case on GPIOs with programmable direction.
> >
> > Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
> > Tested-by: Jeffrey Hugo <jhugo@codeaurora.org>
>
> This patch causes oops on TI's AM335x-ICEv2 board on next-20181011:
>
> [    0.563797] OMAP GPIO hardware version 0.1
> [    0.577589] Unable to handle kernel NULL pointer dereference at virtual address 000002b8
> [    0.586127] pgd = (ptrval)
> [    0.588934] [000002b8] *pgd=00000000
> [    0.592732] Internal error: Oops: 5 [#1] SMP ARM
> [    0.597499] Modules linked in:
> [    0.600668] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.19.0-rc7-next-20181011 #70
> [    0.608466] Hardware name: Generic AM33XX (Flattened Device Tree)
> [    0.614770] PC is at gpiod_hog+0x30/0x154
> [    0.618913] LR is at of_gpiochip_add+0x2fc/0x4e4
> [    0.623671] pc : [<c055213c>]    lr : [<c0553ff0>]    psr: 60000013
> [    0.630130] sp : ce09bba0  ip : cdf08095  fp : 00000000
> [    0.635516] r10: c0bfcf24  r9 : 00000000  r8 : 00000007
> [    0.640902] r7 : cdf08088  r6 : 00000000  r5 : 00000000  r4 : ce191e40
> [    0.647630] r3 : 00000000  r2 : 00000000  r1 : cdf08088  r0 : ce191e40
> [    0.654361] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
> [    0.661718] Control: 10c5387d  Table: 80004019  DAC: 00000051
> [    0.667642] Process swapper/0 (pid: 1, stack limit = 0x(ptrval))
> [...]
> [    0.973593] [<c055213c>] (gpiod_hog) from [<c0553ff0>] (of_gpiochip_add+0x2fc/0x4e4)
> [    0.981588] [<c0553ff0>] (of_gpiochip_add) from [<c05528a0>] (gpiochip_add_data_with_key+
> 0x5a0/0x990)
> [    0.991102] [<c05528a0>] (gpiochip_add_data_with_key) from [<c0556d8c>] (omap_gpio_probe+
> 0x37c/0x75c)
> [    1.000613] [<c0556d8c>] (omap_gpio_probe) from [<c06049c0>] (platform_drv_probe+0x48/0x9
> 8)
> [    1.009237] [<c06049c0>] (platform_drv_probe) from [<c0602a04>] (really_probe+0x220/0x2d4
> )
> [    1.017764] [<c0602a04>] (really_probe) from [<c0602c18>] (driver_probe_device+0x5c/0x164
> )
> [    1.026293] [<c0602c18>] (driver_probe_device) from [<c0600d44>] (bus_for_each_drv+0x54/0
> xb8)
> [    1.035090] [<c0600d44>] (bus_for_each_drv) from [<c060276c>] (__device_attach+0xcc/0x13c
> )
> [    1.043615] [<c060276c>] (__device_attach) from [<c0601b88>] (bus_probe_device+0x88/0x90)
> [    1.052051] [<c0601b88>] (bus_probe_device) from [<c05fea18>] (device_add+0x3d8/0x608)
> [    1.060223] [<c05fea18>] (device_add) from [<c07343b8>] (of_platform_device_create_pdata+
> 0x8c/0xc0)
> [    1.069552] [<c07343b8>] (of_platform_device_create_pdata) from [<c07345c4>] (of_platform
> _bus_create+0x190/0x228)
> [    1.080134] [<c07345c4>] (of_platform_bus_create) from [<c0734610>] (of_platform_bus_crea
> te+0x1dc/0x228)
> [    1.089909] [<c0734610>] (of_platform_bus_create) from [<c073478c>] (of_platform_populate
> +0x5c/0xac)
> [    1.099333] [<c073478c>] (of_platform_populate) from [<c0d12614>] (pdata_quirks_init+0x6c
> /0x90)
> [    1.108306] [<c0d12614>] (pdata_quirks_init) from [<c0d12144>] (omap_generic_init+0xc/0x1
> 8)
> [    1.116933] [<c0d12144>] (omap_generic_init) from [<c0d03eb0>] (customize_machine+0x1c/0x
> 30)
> [    1.125645] [<c0d03eb0>] (customize_machine) from [<c01030e4>] (do_one_initcall+0x80/0x31
> 0)
> [    1.134265] [<c01030e4>] (do_one_initcall) from [<c0d01244>] (kernel_init_freeable+0x3c4/
> 0x4ac)
> [    1.143238] [<c0d01244>] (kernel_init_freeable) from [<c0900f28>] (kernel_init+0x8/0x114)
> [    1.151673] [<c0900f28>] (kernel_init) from [<c01010b4>] (ret_from_fork+0x14/0x20)
> [    1.159475] Exception stack(0xce09bfb0 to 0xce09bff8)
> [    1.164686] bfa0:                                     00000000 00000000 00000000 00000000
> [    1.173119] bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> [    1.181551] bfe0: 00000000 00000000 00000000 00000000 00000013 00000000
> [    1.188378] Code: 0a000002 e3530000 01a09003 159392b4 (e59352b8)
> [    1.194766] ---[ end trace d5c17cd400f50a22 ]---
> [    1.199606] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
> [    1.199606]
> [    1.209052] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000
> 00b
> [    1.209052]  ]---
> [    3.172292] random: fast init done
>
> Full log: https://pastebin.ubuntu.com/p/jG8nN6CTBP/
>
> Reverting this patch from linux-next allows to boot to prompt.
>
> Regards
> Vignesh
>
> > ---
> >  drivers/gpio/gpiolib.c | 27 +++++++++++++--------------
> >  1 file changed, 13 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> > index 907019b67a58..e016b22658ff 100644
> > --- a/drivers/gpio/gpiolib.c
> > +++ b/drivers/gpio/gpiolib.c
> > @@ -1349,20 +1349,6 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
> >
> >       spin_unlock_irqrestore(&gpio_lock, flags);
> >
> > -     for (i = 0; i < chip->ngpio; i++) {
> > -             struct gpio_desc *desc = &gdev->descs[i];
> > -
> > -             desc->gdev = gdev;
> > -
> > -             /* REVISIT: most hardware initializes GPIOs as inputs (often
> > -              * with pullups enabled) so power usage is minimized. Linux
> > -              * code should set the gpio direction first thing; but until
> > -              * it does, and in case chip->get_direction is not set, we may
> > -              * expose the wrong direction in sysfs.
> > -              */
> > -             desc->flags = !chip->direction_input ? (1 << FLAG_IS_OUT) : 0;
> > -     }
> > -
> >  #ifdef CONFIG_PINCTRL
> >       INIT_LIST_HEAD(&gdev->pin_ranges);
> >  #endif
> > @@ -1391,6 +1377,19 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
> >       if (status)
> >               goto err_remove_chip;
> >
> > +     for (i = 0; i < chip->ngpio; i++) {
> > +             struct gpio_desc *desc = &gdev->descs[i];
> > +
> > +             desc->gdev = gdev;
> > +
> > +             if (chip->get_direction && gpiochip_line_is_valid(chip, i))
> > +                     desc->flags = !chip->get_direction(chip, i) ?
> > +                                     (1 << FLAG_IS_OUT) : 0;
> > +             else
> > +                     desc->flags = !chip->direction_input ?
> > +                                     (1 << FLAG_IS_OUT) : 0;
> > +     }
> > +
> >       acpi_gpiochip_add(chip);
> >
> >       machine_gpiochip_add(chip);
> >
>


-- 
Ricardo Ribalda

Re: [PATCH v5 3/3] gpiolib: Show correct direction from the beginning

[Vignesh R]

Hi,

On Thursday 11 October 2018 07:12 PM, Ricardo Ribalda Delgado wrote:
> Hi Vignesh
> 
> Ups, it does not look too good :S . Can you check if this change fixes it:
> 

Below diff works for me. I no longer see crash and gpio-hog seems to be
working. Thanks!

Regards
Vignesh

> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index e016b22658ff..bcd0ef49ce97 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -1349,6 +1349,9 @@ int gpiochip_add_data_with_key(struct gpio_chip
> *chip, void *data,
> 
>         spin_unlock_irqrestore(&gpio_lock, flags);
> 
> +       for (i = 0; i < chip->ngpio; i++)
> +               gdev->descs[i].gdev = gdev;
> +
>  #ifdef CONFIG_PINCTRL
>         INIT_LIST_HEAD(&gdev->pin_ranges);
>  #endif
> @@ -1380,8 +1383,6 @@ int gpiochip_add_data_with_key(struct gpio_chip
> *chip, void *data,
>         for (i = 0; i < chip->ngpio; i++) {
>                 struct gpio_desc *desc = &gdev->descs[i];
> 
> -               desc->gdev = gdev;
> -
>                 if (chip->get_direction && gpiochip_line_is_valid(chip, i))
>                         desc->flags = !chip->get_direction(chip, i) ?
>                                         (1 << FLAG_IS_OUT) : 0;
> 
> 
> Thanks!
> On Thu, Oct 11, 2018 at 2:18 PM Vignesh R <vigneshr@ti.com> wrote:
>>
>> Hi,
>>
>> On Friday 05 October 2018 12:23 PM, Ricardo Ribalda Delgado wrote:
>>> Current code assumes that the direction is input if direction_input
>>> function is set.
>>> This might not be the case on GPIOs with programmable direction.
>>>
>>> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
>>> Tested-by: Jeffrey Hugo <jhugo@codeaurora.org>
>>
>> This patch causes oops on TI's AM335x-ICEv2 board on next-20181011:
>>
>> [    0.563797] OMAP GPIO hardware version 0.1
>> [    0.577589] Unable to handle kernel NULL pointer dereference at virtual address 000002b8
>> [    0.586127] pgd = (ptrval)
>> [    0.588934] [000002b8] *pgd=00000000
>> [    0.592732] Internal error: Oops: 5 [#1] SMP ARM
>> [    0.597499] Modules linked in:
>> [    0.600668] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.19.0-rc7-next-20181011 #70
>> [    0.608466] Hardware name: Generic AM33XX (Flattened Device Tree)
>> [    0.614770] PC is at gpiod_hog+0x30/0x154
>> [    0.618913] LR is at of_gpiochip_add+0x2fc/0x4e4
>> [    0.623671] pc : [<c055213c>]    lr : [<c0553ff0>]    psr: 60000013
>> [    0.630130] sp : ce09bba0  ip : cdf08095  fp : 00000000
>> [    0.635516] r10: c0bfcf24  r9 : 00000000  r8 : 00000007
>> [    0.640902] r7 : cdf08088  r6 : 00000000  r5 : 00000000  r4 : ce191e40
>> [    0.647630] r3 : 00000000  r2 : 00000000  r1 : cdf08088  r0 : ce191e40
>> [    0.654361] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
>> [    0.661718] Control: 10c5387d  Table: 80004019  DAC: 00000051
>> [    0.667642] Process swapper/0 (pid: 1, stack limit = 0x(ptrval))
>> [...]
>> [    0.973593] [<c055213c>] (gpiod_hog) from [<c0553ff0>] (of_gpiochip_add+0x2fc/0x4e4)
>> [    0.981588] [<c0553ff0>] (of_gpiochip_add) from [<c05528a0>] (gpiochip_add_data_with_key+
>> 0x5a0/0x990)
>> [    0.991102] [<c05528a0>] (gpiochip_add_data_with_key) from [<c0556d8c>] (omap_gpio_probe+
>> 0x37c/0x75c)
>> [    1.000613] [<c0556d8c>] (omap_gpio_probe) from [<c06049c0>] (platform_drv_probe+0x48/0x9
>> 8)
>> [    1.009237] [<c06049c0>] (platform_drv_probe) from [<c0602a04>] (really_probe+0x220/0x2d4
>> )
>> [    1.017764] [<c0602a04>] (really_probe) from [<c0602c18>] (driver_probe_device+0x5c/0x164
>> )
>> [    1.026293] [<c0602c18>] (driver_probe_device) from [<c0600d44>] (bus_for_each_drv+0x54/0
>> xb8)
>> [    1.035090] [<c0600d44>] (bus_for_each_drv) from [<c060276c>] (__device_attach+0xcc/0x13c
>> )
>> [    1.043615] [<c060276c>] (__device_attach) from [<c0601b88>] (bus_probe_device+0x88/0x90)
>> [    1.052051] [<c0601b88>] (bus_probe_device) from [<c05fea18>] (device_add+0x3d8/0x608)
>> [    1.060223] [<c05fea18>] (device_add) from [<c07343b8>] (of_platform_device_create_pdata+
>> 0x8c/0xc0)
>> [    1.069552] [<c07343b8>] (of_platform_device_create_pdata) from [<c07345c4>] (of_platform
>> _bus_create+0x190/0x228)
>> [    1.080134] [<c07345c4>] (of_platform_bus_create) from [<c0734610>] (of_platform_bus_crea
>> te+0x1dc/0x228)
>> [    1.089909] [<c0734610>] (of_platform_bus_create) from [<c073478c>] (of_platform_populate
>> +0x5c/0xac)
>> [    1.099333] [<c073478c>] (of_platform_populate) from [<c0d12614>] (pdata_quirks_init+0x6c
>> /0x90)
>> [    1.108306] [<c0d12614>] (pdata_quirks_init) from [<c0d12144>] (omap_generic_init+0xc/0x1
>> 8)
>> [    1.116933] [<c0d12144>] (omap_generic_init) from [<c0d03eb0>] (customize_machine+0x1c/0x
>> 30)
>> [    1.125645] [<c0d03eb0>] (customize_machine) from [<c01030e4>] (do_one_initcall+0x80/0x31
>> 0)
>> [    1.134265] [<c01030e4>] (do_one_initcall) from [<c0d01244>] (kernel_init_freeable+0x3c4/
>> 0x4ac)
>> [    1.143238] [<c0d01244>] (kernel_init_freeable) from [<c0900f28>] (kernel_init+0x8/0x114)
>> [    1.151673] [<c0900f28>] (kernel_init) from [<c01010b4>] (ret_from_fork+0x14/0x20)
>> [    1.159475] Exception stack(0xce09bfb0 to 0xce09bff8)
>> [    1.164686] bfa0:                                     00000000 00000000 00000000 00000000
>> [    1.173119] bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
>> [    1.181551] bfe0: 00000000 00000000 00000000 00000000 00000013 00000000
>> [    1.188378] Code: 0a000002 e3530000 01a09003 159392b4 (e59352b8)
>> [    1.194766] ---[ end trace d5c17cd400f50a22 ]---
>> [    1.199606] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
>> [    1.199606]
>> [    1.209052] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000
>> 00b
>> [    1.209052]  ]---
>> [    3.172292] random: fast init done
>>
>> Full log: https://pastebin.ubuntu.com/p/jG8nN6CTBP/
>>
>> Reverting this patch from linux-next allows to boot to prompt.
>>
>> Regards
>> Vignesh
>>
>>> ---
>>>  drivers/gpio/gpiolib.c | 27 +++++++++++++--------------
>>>  1 file changed, 13 insertions(+), 14 deletions(-)
>>>
>>> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
>>> index 907019b67a58..e016b22658ff 100644
>>> --- a/drivers/gpio/gpiolib.c
>>> +++ b/drivers/gpio/gpiolib.c
>>> @@ -1349,20 +1349,6 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
>>>
>>>       spin_unlock_irqrestore(&gpio_lock, flags);
>>>
>>> -     for (i = 0; i < chip->ngpio; i++) {
>>> -             struct gpio_desc *desc = &gdev->descs[i];
>>> -
>>> -             desc->gdev = gdev;
>>> -
>>> -             /* REVISIT: most hardware initializes GPIOs as inputs (often
>>> -              * with pullups enabled) so power usage is minimized. Linux
>>> -              * code should set the gpio direction first thing; but until
>>> -              * it does, and in case chip->get_direction is not set, we may
>>> -              * expose the wrong direction in sysfs.
>>> -              */
>>> -             desc->flags = !chip->direction_input ? (1 << FLAG_IS_OUT) : 0;
>>> -     }
>>> -
>>>  #ifdef CONFIG_PINCTRL
>>>       INIT_LIST_HEAD(&gdev->pin_ranges);
>>>  #endif
>>> @@ -1391,6 +1377,19 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
>>>       if (status)
>>>               goto err_remove_chip;
>>>
>>> +     for (i = 0; i < chip->ngpio; i++) {
>>> +             struct gpio_desc *desc = &gdev->descs[i];
>>> +
>>> +             desc->gdev = gdev;
>>> +
>>> +             if (chip->get_direction && gpiochip_line_is_valid(chip, i))
>>> +                     desc->flags = !chip->get_direction(chip, i) ?
>>> +                                     (1 << FLAG_IS_OUT) : 0;
>>> +             else
>>> +                     desc->flags = !chip->direction_input ?
>>> +                                     (1 << FLAG_IS_OUT) : 0;
>>> +     }
>>> +
>>>       acpi_gpiochip_add(chip);
>>>
>>>       machine_gpiochip_add(chip);
>>>
>>
> 
> 

Re: [PATCH v5 3/3] gpiolib: Show correct direction from the beginning

[Linus Walleij]

On Fri, Oct 12, 2018 at 7:59 AM Vignesh R <vigneshr@ti.com> wrote:
> On Thursday 11 October 2018 07:12 PM, Ricardo Ribalda Delgado wrote:
> > Hi Vignesh
> >
> > Ups, it does not look too good :S . Can you check if this change fixes it:
> >
>
> Below diff works for me. I no longer see crash and gpio-hog seems to be
> working. Thanks!

Ricardo can you send a patch with a Fixes: tag and Vignesh's
Tested-by/Reported-by?

Yours,
Linus Walleij

REGRESSION: [PATCH v5 3/3] gpiolib: Show correct direction from the beginning

[Marcel Ziswiler]

On Fri, 2018-10-05 at 08:53 +0200, Ricardo Ribalda Delgado wrote:
> Current code assumes that the direction is input if direction_input
> function is set.
> This might not be the case on GPIOs with programmable direction.

Unfortunately, this breaks at least Apalis T30 and Apalis TK1. Enabling
earlycon reveals the following:

[    0.721165] Unable to handle kernel NULL pointer dereference at
virtual addre
ss 000001f8
[    0.729570] pgd = (ptrval)
[    0.732417] [000001f8] *pgd=00000000
[    0.736137] Internal error: Oops: 5 [#1] PREEMPT SMP ARM
[    0.741643] Modules linked in:
[    0.744819] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.19.0-rc7-
next-2018101
2 #6
[    0.752579] Hardware name: NVIDIA Tegra SoC (Flattened Device Tree)
[    0.759092] PC is at gpiod_hog+0x2c/0x150
[    0.763255] LR is at of_gpiochip_add+0x34c/0x510
[    0.768040] pc : [<c044c9a4>]    lr : [<c044e840>]    psr: 60000013
[    0.774534] sp : f68c9cd0  ip : 00000000  fp : f68c9d18
[    0.779946] r10: c0ccb3c8  r9 : 00000000  r8 : 00000000
[    0.785359] r7 : 00000007  r6 : c20019c4  r5 : f6a7b970  r4 :
f6a78a24
[    0.792121] r3 : 00000000  r2 : 00000000  r1 : c20019c4  r0 :
f6a7b970
[    0.798884] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA
ARM  Segment none
[    0.806273] Control: 10c5387d  Table: 8000404a  DAC: 00000051
[    0.812227] Process swapper/0 (pid: 1, stack limit = 0x(ptrval))
[    0.818451] Stack: (0xf68c9cd0 to 0xf68ca000)
...
[    1.043490] [<c044c9a4>] (gpiod_hog) from [<c044e840>]
(of_gpiochip_add+0x34c/0x510)
[    1.051531] [<c044e840>] (of_gpiochip_add) from [<c044d1cc>]
(gpiochip_add_data_with_key+0x668/0x958)
[    1.061091] [<c044d1cc>] (gpiochip_add_data_with_key) from
[<c044d504>] (devm_gpiochip_add_data+0x48/0x84)
[    1.071109] [<c044d504>] (devm_gpiochip_add_data) from [<c045166c>]
(tegra_gpio_probe+0x2d4/0x420)
[    1.080413] [<c045166c>] (tegra_gpio_probe) from [<c0574040>]
(platform_drv_probe+0x48/0x98)
[    1.089171] [<c0574040>] (platform_drv_probe) from [<c0572164>]
(really_probe+0x1e0/0x2cc)
[    1.097746] [<c0572164>] (really_probe) from [<c05723b4>]
(driver_probe_device+0x60/0x16c)
[    1.106317] [<c05723b4>] (driver_probe_device) from [<c057259c>]
(__driver_attach+0xdc/0xe0)
[    1.115071] [<c057259c>] (__driver_attach) from [<c05704a8>]
(bus_for_each_dev+0x74/0xb4)
[    1.123554] [<c05704a8>] (bus_for_each_dev) from [<c0571644>]
(bus_add_driver+0x1c0/0x204)
[    1.132122] [<c0571644>] (bus_add_driver) from [<c05731b8>]
(driver_register+0x74/0x108)
[    1.140521] [<c05731b8>] (driver_register) from [<c0102ebc>]
(do_one_initcall+0x54/0x284)
[    1.149015] [<c0102ebc>] (do_one_initcall) from [<c0e01134>]
(kernel_init_freeable+0x2d0/0x364)
[    1.158043] [<c0e01134>] (kernel_init_freeable) from [<c0a24c78>]
(kernel_init+0x8/0x110)
[    1.166527] [<c0a24c78>] (kernel_init) from [<c01010e8>]
(ret_from_fork+0x14/0x2c)
[    1.174375] Exception stack(0xf68c9fb0 to 0xf68c9ff8)
...

Just reverting this one patch made it boot again. I will investigate
further...

> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
> ---
>  drivers/gpio/gpiolib.c | 27 +++++++++++++--------------
>  1 file changed, 13 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index 907019b67a58..e016b22658ff 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -1349,20 +1349,6 @@ int gpiochip_add_data_with_key(struct
> gpio_chip *chip, void *data,
>  
>  	spin_unlock_irqrestore(&gpio_lock, flags);
>  
> -	for (i = 0; i < chip->ngpio; i++) {
> -		struct gpio_desc *desc = &gdev->descs[i];
> -
> -		desc->gdev = gdev;
> -
> -		/* REVISIT: most hardware initializes GPIOs as
> inputs (often
> -		 * with pullups enabled) so power usage is
> minimized. Linux
> -		 * code should set the gpio direction first thing;
> but until
> -		 * it does, and in case chip->get_direction is not
> set, we may
> -		 * expose the wrong direction in sysfs.
> -		 */
> -		desc->flags = !chip->direction_input ? (1 <<
> FLAG_IS_OUT) : 0;
> -	}
> -
>  #ifdef CONFIG_PINCTRL
>  	INIT_LIST_HEAD(&gdev->pin_ranges);
>  #endif
> @@ -1391,6 +1377,19 @@ int gpiochip_add_data_with_key(struct
> gpio_chip *chip, void *data,
>  	if (status)
>  		goto err_remove_chip;
>  
> +	for (i = 0; i < chip->ngpio; i++) {
> +		struct gpio_desc *desc = &gdev->descs[i];
> +
> +		desc->gdev = gdev;
> +
> +		if (chip->get_direction &&
> gpiochip_line_is_valid(chip, i))
> +			desc->flags = !chip->get_direction(chip, i)
> ?
> +					(1 << FLAG_IS_OUT) : 0;
> +		else
> +			desc->flags = !chip->direction_input ?
> +					(1 << FLAG_IS_OUT) : 0;
> +	}
> +
>  	acpi_gpiochip_add(chip);
>  
>  	machine_gpiochip_add(chip);

Re: REGRESSION: [PATCH v5 3/3] gpiolib: Show correct direction from the beginning

[Linus Walleij]

On Fri, Oct 12, 2018 at 11:00 AM Marcel Ziswiler
<marcel.ziswiler@toradex.com> wrote:
> On Fri, 2018-10-05 at 08:53 +0200, Ricardo Ribalda Delgado wrote:
> > Current code assumes that the direction is input if direction_input
> > function is set.
> > This might not be the case on GPIOs with programmable direction.
>
> Unfortunately, this breaks at least Apalis T30 and Apalis TK1. Enabling
> earlycon reveals the following:

Does this (just applied) patch fix the issue?
https://marc.info/?l=linux-kernel&m=153932470412013&w=2

Yours,
Linus Walleij

Re: REGRESSION: [PATCH v5 3/3] gpiolib: Show correct direction from the beginning

[Marcel Ziswiler]

On Fri, 2018-10-12 at 11:08 +0200, Linus Walleij wrote:
> On Fri, Oct 12, 2018 at 11:00 AM Marcel Ziswiler
> <marcel.ziswiler@toradex.com> wrote:
> > On Fri, 2018-10-05 at 08:53 +0200, Ricardo Ribalda Delgado wrote:
> > > Current code assumes that the direction is input if
> > > direction_input
> > > function is set.
> > > This might not be the case on GPIOs with programmable direction.
> > 
> > Unfortunately, this breaks at least Apalis T30 and Apalis TK1.
> > Enabling
> > earlycon reveals the following:
> 
> Does this (just applied) patch fix the issue?
> https://marc.info/?l=linux-kernel&m=153932470412013&w=2

Yes, that cuts it. Thanks!

> Yours,
> Linus Walleij