Re: [RFC PATCH 1/2] of: unittest: add overlay gpio test to catch gpio hog problem

From: Rob Herring
Date: Tue Jan 21 2020 - 18:02:42 EST

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On Wed, Jan 15, 2020 at 12:47:07AM -0600, frowand.list@xxxxxxxxx wrote:
> From: Frank Rowand <frank.rowand@xxxxxxxx>
>
> Geert reports that gpio hog nodes are not properly processed when
> the gpio hog node is added via an overlay reply and provides an
> RFC patch to fix the problem [1].
>
> Add a unittest that shows the problem. Unittest will report "1 failed"
> test before applying Geert's RFC patch and "0 failed" after applying
> Geert's RFC patch.
>
> [1] https://lore.kernel.org/linux-devicetree/20191230133852.5890-1-geert+renesas@xxxxxxxxx/
>
> Signed-off-by: Frank Rowand <frank.rowand@xxxxxxxx>
> ---
>
> There are checkpatch warnings.
> - The lines over 80 characters are consistent with unittest.c style
> - The undocumented compatibles are restricted to use by unittest
> and should not be documented under Documentation
>
> This unittest was also valuable in that it allowed me to explore
> possible issues related to the proposed solution to the gpio hog
> problem.
>
> drivers/of/unittest-data/Makefile | 8 +-
> drivers/of/unittest-data/overlay_gpio_01.dts | 23 +++
> drivers/of/unittest-data/overlay_gpio_02a.dts | 16 ++
> drivers/of/unittest-data/overlay_gpio_02b.dts | 16 ++
> drivers/of/unittest-data/overlay_gpio_03.dts | 23 +++
> drivers/of/unittest-data/overlay_gpio_04a.dts | 16 ++
> drivers/of/unittest-data/overlay_gpio_04b.dts | 16 ++
> drivers/of/unittest.c | 257 ++++++++++++++++++++++++++
> 8 files changed, 374 insertions(+), 1 deletion(-)
> create mode 100644 drivers/of/unittest-data/overlay_gpio_01.dts
> create mode 100644 drivers/of/unittest-data/overlay_gpio_02a.dts
> create mode 100644 drivers/of/unittest-data/overlay_gpio_02b.dts
> create mode 100644 drivers/of/unittest-data/overlay_gpio_03.dts
> create mode 100644 drivers/of/unittest-data/overlay_gpio_04a.dts
> create mode 100644 drivers/of/unittest-data/overlay_gpio_04b.dts
>
> diff --git a/drivers/of/unittest-data/Makefile b/drivers/of/unittest-data/Makefile
> index 9b6807065827..009f4045c8e4 100644
> --- a/drivers/of/unittest-data/Makefile
> +++ b/drivers/of/unittest-data/Makefile
> @@ -21,7 +21,13 @@ obj-$(CONFIG_OF_OVERLAY) += overlay.dtb.o \
> overlay_bad_add_dup_prop.dtb.o \
> overlay_bad_phandle.dtb.o \
> overlay_bad_symbol.dtb.o \
> - overlay_base.dtb.o
> + overlay_base.dtb.o \
> + overlay_gpio_01.dtb.o \
> + overlay_gpio_02a.dtb.o \
> + overlay_gpio_02b.dtb.o \
> + overlay_gpio_03.dtb.o \
> + overlay_gpio_04a.dtb.o \
> + overlay_gpio_04b.dtb.o
>
> # enable creation of __symbols__ node
> DTC_FLAGS_overlay += -@
> diff --git a/drivers/of/unittest-data/overlay_gpio_01.dts b/drivers/of/unittest-data/overlay_gpio_01.dts
> new file mode 100644
> index 000000000000..f039e8bce3b6
> --- /dev/null
> +++ b/drivers/of/unittest-data/overlay_gpio_01.dts
> @@ -0,0 +1,23 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/dts-v1/;
> +/plugin/;
> +
> +&unittest_test_bus {
> + #address-cells = <1>;
> + #size-cells = <0>;
> + gpio_01 {

gpio@0

> + compatible = "unittest-gpio";

There's a mock GPIO driver and I think there was a binding proposed at
some point for some sort of GPIO testing device binding. Maybe that can
save another test driver.

> + reg = <0>;
> + gpio-controller;
> + #gpio-cells = <2>;
> + ngpios = <2>;
> + gpio-line-names = "line-A", "line-B";
> +
> + line_b {

line-b

> + gpio-hog;
> + gpios = <2 0>;
> + input;
> + line-name = "line-B-input";
> + };
> + };
> +};
> diff --git a/drivers/of/unittest-data/overlay_gpio_02a.dts b/drivers/of/unittest-data/overlay_gpio_02a.dts
> new file mode 100644
> index 000000000000..cdafab604793
> --- /dev/null
> +++ b/drivers/of/unittest-data/overlay_gpio_02a.dts
> @@ -0,0 +1,16 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/dts-v1/;
> +/plugin/;
> +
> +&unittest_test_bus {
> + #address-cells = <1>;
> + #size-cells = <0>;
> + gpio_02 {
> + compatible = "unittest-gpio";
> + reg = <1>;
> + gpio-controller;
> + #gpio-cells = <2>;
> + ngpios = <2>;
> + gpio-line-names = "line-A", "line-B";
> + };
> +};
> diff --git a/drivers/of/unittest-data/overlay_gpio_02b.dts b/drivers/of/unittest-data/overlay_gpio_02b.dts
> new file mode 100644
> index 000000000000..0cea0dccafba
> --- /dev/null
> +++ b/drivers/of/unittest-data/overlay_gpio_02b.dts
> @@ -0,0 +1,16 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/dts-v1/;
> +/plugin/;
> +
> +&unittest_test_bus {
> + #address-cells = <1>;
> + #size-cells = <0>;
> + gpio_02 {
> + line_a {
> + gpio-hog;
> + gpios = <1 0>;
> + input;
> + line-name = "line-A-input";
> + };
> + };
> +};
> diff --git a/drivers/of/unittest-data/overlay_gpio_03.dts b/drivers/of/unittest-data/overlay_gpio_03.dts
> new file mode 100644
> index 000000000000..1d5c680fa254
> --- /dev/null
> +++ b/drivers/of/unittest-data/overlay_gpio_03.dts
> @@ -0,0 +1,23 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/dts-v1/;
> +/plugin/;
> +
> +&unittest_test_bus {
> + #address-cells = <1>;
> + #size-cells = <0>;
> + gpio_03 {
> + compatible = "unittest-gpio";
> + reg = <0>;
> + gpio-controller;
> + #gpio-cells = <2>;
> + ngpios = <2>;
> + gpio-line-names = "line-A", "line-B", "line-C", "line-D";
> +
> + line_d {
> + gpio-hog;
> + gpios = <4 0>;
> + input;
> + line-name = "line-D-input";
> + };
> + };
> +};
> diff --git a/drivers/of/unittest-data/overlay_gpio_04a.dts b/drivers/of/unittest-data/overlay_gpio_04a.dts
> new file mode 100644
> index 000000000000..d2482cde310e
> --- /dev/null
> +++ b/drivers/of/unittest-data/overlay_gpio_04a.dts
> @@ -0,0 +1,16 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/dts-v1/;
> +/plugin/;
> +
> +&unittest_test_bus {
> + #address-cells = <1>;
> + #size-cells = <0>;
> + gpio_04 {
> + compatible = "unittest-gpio";
> + reg = <1>;
> + gpio-controller;
> + #gpio-cells = <2>;
> + ngpios = <2>;
> + gpio-line-names = "line-A", "line-B", "line-C", "line-D";
> + };
> +};
> diff --git a/drivers/of/unittest-data/overlay_gpio_04b.dts b/drivers/of/unittest-data/overlay_gpio_04b.dts
> new file mode 100644
> index 000000000000..70ad05d759f9
> --- /dev/null
> +++ b/drivers/of/unittest-data/overlay_gpio_04b.dts
> @@ -0,0 +1,16 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/dts-v1/;
> +/plugin/;
> +
> +&unittest_test_bus {
> + #address-cells = <1>;
> + #size-cells = <0>;
> + gpio_04 {
> + line_c {
> + gpio-hog;
> + gpios = <3 0>;
> + input;
> + line-name = "line-C-input";
> + };
> + };
> +};
> diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
> index 68b87587b2ef..db0a6f4103a4 100644
> --- a/drivers/of/unittest.c
> +++ b/drivers/of/unittest.c
> @@ -24,6 +24,7 @@
>
> #include <linux/i2c.h>
> #include <linux/i2c-mux.h>
> +#include <linux/gpio/driver.h>
>
> #include <linux/bitops.h>
>
> @@ -46,6 +47,101 @@
> failed; \
> })
>
> +/*
> + * Expected message may have a message level other than KERN_INFO.
> + * Print the expected message only if the current loglevel will allow
> + * the actual message to print.
> + */
> +#define EXPECT_BEGIN(level, fmt, ...) \
> + printk(level pr_fmt("EXPECT \\ : ") fmt, ##__VA_ARGS__)
> +
> +#define EXPECT_END(level, fmt, ...) \
> + printk(level pr_fmt("EXPECT / : ") fmt, ##__VA_ARGS__)

When I first saw this, I thought of kunit...

Just wondering if this is a standard way to express this, and if not, is
there?

> +
> +struct unittest_gpio_dev {
> + void __iomem *base;
> + struct gpio_chip chip;
> + spinlock_t gpio_lock;

base and gpio_lock aren't used.

> +};
> +
> +static int unittest_gpio_chip_request_count;
> +static int unittest_gpio_probe_count;
> +static int unittest_gpio_probe_pass_count;
> +
> +static int unittest_gpio_chip_request(struct gpio_chip *chip, unsigned int offset)
> +{
> + unittest_gpio_chip_request_count++;
> +
> + pr_debug("%s(): %s %d %d\n", __func__, chip->label, offset,
> + unittest_gpio_chip_request_count);
> + return 0;
> +}
> +
> +static int unittest_gpio_probe(struct platform_device *pdev)
> +{
> + struct unittest_gpio_dev *devptr;
> + int ret;
> +
> + unittest_gpio_probe_count++;
> +
> + devptr = kzalloc(sizeof(*devptr), GFP_KERNEL);
> + if (!devptr)
> + return -ENOMEM;
> +
> + spin_lock_init(&devptr->gpio_lock);
> +
> + platform_set_drvdata(pdev, devptr);
> +
> + devptr->chip.of_node = pdev->dev.of_node;
> + devptr->chip.label = "of-unittest-gpio";
> + devptr->chip.base = -1; /* dynamic allocation */
> + devptr->chip.ngpio = 5;
> + devptr->chip.request = unittest_gpio_chip_request;
> +
> + ret = gpiochip_add_data(&devptr->chip, NULL);
> +
> + unittest(!ret,
> + "gpiochip_add_data() for node @%pOF failed, ret = %d\n", devptr->chip.of_node, ret);
> +
> + if (!ret)
> + unittest_gpio_probe_pass_count++;
> + return ret;
> +}
> +
> +static int unittest_gpio_remove(struct platform_device *pdev)
> +{
> + struct unittest_gpio_dev *gdev = platform_get_drvdata(pdev);
> + struct device *dev = &pdev->dev;
> + struct device_node *np = pdev->dev.of_node;
> +
> + dev_dbg(dev, "%s for node @%pOF\n", __func__, np);
> +
> + if (!gdev)
> + return -EINVAL;
> +
> + if (gdev->chip.base != -1)
> + gpiochip_remove(&gdev->chip);
> +
> + platform_set_drvdata(pdev, NULL);
> + kfree(pdev);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id unittest_gpio_id[] = {
> + { .compatible = "unittest-gpio", },
> + {}
> +};
> +
> +static struct platform_driver unittest_gpio_driver = {
> + .probe = unittest_gpio_probe,
> + .remove = unittest_gpio_remove,
> + .driver = {
> + .name = "unittest-gpio",
> + .of_match_table = of_match_ptr(unittest_gpio_id),
> + },
> +};
> +
> static void __init of_unittest_find_node_by_name(void)
> {
> struct device_node *np;
> @@ -2183,6 +2279,153 @@ static inline void of_unittest_overlay_i2c_15(void) { }
>
> #endif
>
> +static void __init of_unittest_overlay_gpio(void)
> +{
> + int chip_request_count;
> + int probe_pass_count;
> + int ret;
> +
> + /*
> + * tests: apply overlays before registering driver
> + * Similar to installing a driver as a module, the
> + * driver is registered after applying the overlays.
> + *
> + * - apply overlay_gpio_01
> + * - apply overlay_gpio_02a
> + * - apply overlay_gpio_02b
> + * - register driver
> + *
> + * register driver will result in
> + * - probe and processing gpio hog for overlay_gpio_01
> + * - probe for overlay_gpio_02a
> + * - processing gpio for overlay_gpio_02b
> + */
> +
> + probe_pass_count = unittest_gpio_probe_pass_count;
> + chip_request_count = unittest_gpio_chip_request_count;
> +
> + /*
> + * overlay_gpio_01 contains gpio node and child gpio hog node
> + * overlay_gpio_02a contains gpio node
> + * overlay_gpio_02b contains child gpio hog node
> + */
> +
> + unittest(overlay_data_apply("overlay_gpio_01", NULL),
> + "Adding overlay 'overlay_gpio_01' failed\n");
> +
> + unittest(overlay_data_apply("overlay_gpio_02a", NULL),
> + "Adding overlay 'overlay_gpio_02a' failed\n");
> +
> + unittest(overlay_data_apply("overlay_gpio_02b", NULL),
> + "Adding overlay 'overlay_gpio_02b' failed\n");
> +
> + /*
> + * messages are the result of the probes, after the
> + * driver is registered
> + */
> +
> + EXPECT_BEGIN(KERN_INFO,
> + "GPIO line <<int>> (line-B-input) hogged as input\n");
> +
> + EXPECT_BEGIN(KERN_INFO,
> + "GPIO line <<int>> (line-A-input) hogged as input\n");
> +
> + ret = platform_driver_register(&unittest_gpio_driver);
> + if (unittest(ret == 0, "could not register unittest gpio driver\n"))
> + return;
> +
> + EXPECT_END(KERN_INFO,
> + "GPIO line <<int>> (line-A-input) hogged as input\n");
> + EXPECT_END(KERN_INFO,
> + "GPIO line <<int>> (line-B-input) hogged as input\n");
> +
> + unittest(probe_pass_count + 2 == unittest_gpio_probe_pass_count,
> + "unittest_gpio_probe() failed or not called\n");
> +
> + unittest(chip_request_count + 2 == unittest_gpio_chip_request_count,
> + "unittest_gpio_chip_request() called %d times (expected 1 time)\n",
> + unittest_gpio_chip_request_count - chip_request_count);
> +
> + /*
> + * tests: apply overlays after registering driver
> + *
> + * Similar to a driver built-in to the kernel, the
> + * driver is registered before applying the overlays.
> + *
> + * overlay_gpio_03 contains gpio node and child gpio hog node
> + *
> + * - apply overlay_gpio_03
> + *
> + * apply overlay will result in
> + * - probe and processing gpio hog.
> + */
> +
> + probe_pass_count = unittest_gpio_probe_pass_count;
> + chip_request_count = unittest_gpio_chip_request_count;
> +
> + EXPECT_BEGIN(KERN_INFO,
> + "GPIO line <<int>> (line-D-input) hogged as input\n");
> +
> + /* overlay_gpio_03 contains gpio node and child gpio hog node */
> +
> + unittest(overlay_data_apply("overlay_gpio_03", NULL),
> + "Adding overlay 'overlay_gpio_03' failed\n");
> +
> + EXPECT_END(KERN_INFO,
> + "GPIO line <<int>> (line-D-input) hogged as input\n");
> +
> + unittest(probe_pass_count + 1 == unittest_gpio_probe_pass_count,
> + "unittest_gpio_probe() failed or not called\n");
> +
> + unittest(chip_request_count + 1 == unittest_gpio_chip_request_count,
> + "unittest_gpio_chip_request() called %d times (expected 1 time)\n",
> + unittest_gpio_chip_request_count - chip_request_count);
> +
> + /*
> + * overlay_gpio_04a contains gpio node
> + *
> + * - apply overlay_gpio_04a
> + *
> + * apply the overlay will result in
> + * - probe for overlay_gpio_04a
> + */
> +
> + probe_pass_count = unittest_gpio_probe_pass_count;
> + chip_request_count = unittest_gpio_chip_request_count;
> +
> + /* overlay_gpio_04a contains gpio node */
> +
> + unittest(overlay_data_apply("overlay_gpio_04a", NULL),
> + "Adding overlay 'overlay_gpio_04a' failed\n");
> +
> + unittest(probe_pass_count + 1 == unittest_gpio_probe_pass_count,
> + "unittest_gpio_probe() failed or not called\n");
> +
> + /*
> + * overlay_gpio_04b contains child gpio hog node
> + *
> + * - apply overlay_gpio_04b
> + *
> + * apply the overlay will result in
> + * - processing gpio for overlay_gpio_04b
> + */
> +
> + EXPECT_BEGIN(KERN_INFO,
> + "GPIO line <<int>> (line-C-input) hogged as input\n");
> +
> + /* overlay_gpio_04b contains child gpio hog node */
> +
> + unittest(overlay_data_apply("overlay_gpio_04b", NULL),
> + "Adding overlay 'overlay_gpio_04b' failed\n");
> +
> + EXPECT_END(KERN_INFO,
> + "GPIO line <<int>> (line-C-input) hogged as input\n");
> +
> + unittest(chip_request_count + 1 == unittest_gpio_chip_request_count,
> + "unittest_gpio_chip_request() called %d times (expected 1 time)\n",
> + unittest_gpio_chip_request_count - chip_request_count);
> +}
> +
> static void __init of_unittest_overlay(void)
> {
> struct device_node *bus_np = NULL;
> @@ -2242,6 +2485,8 @@ static void __init of_unittest_overlay(void)
> of_unittest_overlay_i2c_cleanup();
> #endif
>
> + of_unittest_overlay_gpio();
> +
> of_unittest_destroy_tracked_overlays();
>
> out:
> @@ -2295,6 +2540,12 @@ struct overlay_info {
> OVERLAY_INFO_EXTERN(overlay_12);
> OVERLAY_INFO_EXTERN(overlay_13);
> OVERLAY_INFO_EXTERN(overlay_15);
> +OVERLAY_INFO_EXTERN(overlay_gpio_01);
> +OVERLAY_INFO_EXTERN(overlay_gpio_02a);
> +OVERLAY_INFO_EXTERN(overlay_gpio_02b);
> +OVERLAY_INFO_EXTERN(overlay_gpio_03);
> +OVERLAY_INFO_EXTERN(overlay_gpio_04a);
> +OVERLAY_INFO_EXTERN(overlay_gpio_04b);
> OVERLAY_INFO_EXTERN(overlay_bad_add_dup_node);
> OVERLAY_INFO_EXTERN(overlay_bad_add_dup_prop);
> OVERLAY_INFO_EXTERN(overlay_bad_phandle);
> @@ -2319,6 +2570,12 @@ struct overlay_info {
> OVERLAY_INFO(overlay_12, 0),
> OVERLAY_INFO(overlay_13, 0),
> OVERLAY_INFO(overlay_15, 0),
> + OVERLAY_INFO(overlay_gpio_01, 0),
> + OVERLAY_INFO(overlay_gpio_02a, 0),
> + OVERLAY_INFO(overlay_gpio_02b, 0),
> + OVERLAY_INFO(overlay_gpio_03, 0),
> + OVERLAY_INFO(overlay_gpio_04a, 0),
> + OVERLAY_INFO(overlay_gpio_04b, 0),
> OVERLAY_INFO(overlay_bad_add_dup_node, -EINVAL),
> OVERLAY_INFO(overlay_bad_add_dup_prop, -EINVAL),
> OVERLAY_INFO(overlay_bad_phandle, -EINVAL),
> --
> Frank Rowand <frank.rowand@xxxxxxxx>
>

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