Subject: Fwd: [PATCH 4/4] [v3] pinctrl: qcom: qdf2xxx: add support for new ACPI HID QCOM8002

From: [email-masked] (Varadarajan Narayanan)
Date: Wed, 15 Nov 2017 12:17:23 +0530

Timur,

> Newer versions of the firmware for the Qualcomm Datacenter Technologies
> QDF2400 restricts access to a subset of the GPIOs on the TLMM.  To
> prevent older kernels from accidentally accessing the restricted GPIOs,
> we change the ACPI HID for the TLMM block from QCOM8001 to QCOM8002,
> and introduce a new property "gpios".  This property is an array of
> specific GPIOs that are accessible.  When an older kernel boots on
> newer (restricted) firmware, it will fail to probe.
>
> To implement the sparse GPIO map, we register all of the GPIOs, but set
> the pin count for the unavailable GPIOs to zero.  The pinctrl-msm
> driver will block those unavailable GPIOs from being accessed.
>
> To allow newer kernels to support older firmware, the driver retains
> support for QCOM8001.
>
> Signed-off-by: Timur Tabi <[email-masked]>
> ---
>  drivers/pinctrl/qcom/pinctrl-qdf2xxx.c | 145 +++++++++++++++++++++++++--------
>  1 file changed, 109 insertions(+), 36 deletions(-)
>
> diff --git a/drivers/pinctrl/qcom/pinctrl-qdf2xxx.c b/drivers/pinctrl/qcom/pinctrl-qdf2xxx.c
> index bb3ce5c3e18b..37f746f6eb8c 100644
> --- a/drivers/pinctrl/qcom/pinctrl-qdf2xxx.c
> +++ b/drivers/pinctrl/qcom/pinctrl-qdf2xxx.c
> @@ -38,68 +38,147 @@
>  /* maximum size of each gpio name (enough room for "gpioXXX" + null) */
>  #define NAME_SIZE	8
>
> +enum {
> +	QDF2XXX_V1,
> +	QDF2XXX_V2,
> +};
> +
> +static const struct acpi_device_id qdf2xxx_acpi_ids[] = {
> +	{"QCOM8001", QDF2XXX_V1},
> +	{"QCOM8002", QDF2XXX_V2},
> +	{},
> +};
> +MODULE_DEVICE_TABLE(acpi, qdf2xxx_acpi_ids);
> +
>  static int qdf2xxx_pinctrl_probe(struct platform_device *pdev)
>  {
> +	const struct acpi_device_id *id =
> +		acpi_match_device(qdf2xxx_acpi_ids, &pdev->dev);
>  	struct pinctrl_pin_desc *pins;
>  	struct msm_pingroup *groups;
>  	char (*names)[NAME_SIZE];
>  	unsigned int i;
>  	u32 num_gpios;
> +	unsigned int avail_gpios; /* The number of GPIOs we support */
> +	u16 *gpios; /* An array of supported GPIOs */
>  	int ret;
>
>  	/* Query the number of GPIOs from ACPI */
>  	ret = device_property_read_u32(&pdev->dev, "num-gpios", &num_gpios);
>  	if (ret < 0) {
> -		dev_warn(&pdev->dev, "missing num-gpios property\n");
> +		dev_err(&pdev->dev, "missing 'num-gpios' property\n");
>  		return ret;
>  	}
> -
>  	if (!num_gpios || num_gpios > MAX_GPIOS) {
> -		dev_warn(&pdev->dev, "invalid num-gpios property\n");
> +		dev_err(&pdev->dev, "invalid 'num-gpios' property\n");
>  		return -ENODEV;
>  	}
>
> +	/*
> +	 * The QCOM8001 HID contains only the number of GPIOs, and assumes
> +	 * that all of them are available. avail_gpios is the same as num_gpios.
> +	 *
> +	 * The QCOM8002 HID introduces the 'gpios' DSD, which lists
> +	 * specific GPIOs that the driver is allowed to access.
> +	 *
> +	 * The make the common code simpler, in both cases we create an
> +	 * array of GPIOs that are accessible.  So for QCOM8001, that would
> +	 * be all of the GPIOs.
> +	 */
> +	if (id->driver_data == QDF2XXX_V1) {
> +		avail_gpios = num_gpios;
> +
> +		gpios = devm_kcalloc(&pdev->dev, avail_gpios, sizeof(gpios[0]),
> +				     GFP_KERNEL);

Wouldn't kmalloc suffice since the array gets initialized just below.

> +		if (!gpios)
> +			return -ENOMEM;
> +
> +		for (i = 0; i < avail_gpios; i++)
> +			gpios[i] = i;
> +	} else {
> +		/* The number of GPIOs in the approved list */
> +		ret = device_property_read_u16_array(&pdev->dev, "gpios",
> +						     NULL, 0);
> +		if (ret < 0) {
> +			dev_err(&pdev->dev, "missing 'num-gpios' property\n");
> +			return ret;
> +		}
> +		if (!ret || ret > MAX_GPIOS) {

Instead of ret > MAX_GPIOS, should we check for ret > num_gpios?

> +			dev_err(&pdev->dev, "invalid 'num-gpios' property\n");
> +			return -ENODEV;
> +		}

In both the above error messages 'num-gpios' should be 'gpios'

> +		avail_gpios = ret;
> +
> +		gpios = devm_kcalloc(&pdev->dev, avail_gpios, sizeof(gpios[0]),
> +				     GFP_KERNEL);

devm_kmalloc?

Thanks
Varada

> +		if (!gpios)
> +			return -ENOMEM;
> +
> +		ret = device_property_read_u16_array(&pdev->dev, "gpios", gpios,
> +						     avail_gpios);
> +		if (ret < 0) {
> +			dev_err(&pdev->dev, "could not read list of GPIOs\n");
> +			return ret;
> +		}
> +
> +		/*
> +		 * Because we have a specific list of GPIOs, the GPIO map
> +		 * is 'sparse'.
> +		 */
> +		qdf2xxx_pinctrl.sparse = true;
> +	}
> +
>  	pins = devm_kcalloc(&pdev->dev, num_gpios,
>  		sizeof(struct pinctrl_pin_desc), GFP_KERNEL);
>  	groups = devm_kcalloc(&pdev->dev, num_gpios,
>  		sizeof(struct msm_pingroup), GFP_KERNEL);
> -	names = devm_kcalloc(&pdev->dev, num_gpios, NAME_SIZE, GFP_KERNEL);
> +	names = devm_kcalloc(&pdev->dev, avail_gpios, NAME_SIZE, GFP_KERNEL);
>
>  	if (!pins || !groups || !names)
>  		return -ENOMEM;
>
> +	/*
> +	 * Initialize the array.  GPIOs not listed in the 'gpios' array
> +	 * still need a number, but nothing else.
> +	 */
>  	for (i = 0; i < num_gpios; i++) {
> -		snprintf(names[i], NAME_SIZE, "gpio%u", i);
> -
>  		pins[i].number = i;
> -		pins[i].name = names[i];
> -
> -		groups[i].npins = 1;
> -		groups[i].name = names[i];
>  		groups[i].pins = &pins[i].number;
> +	}
>
> -		groups[i].ctl_reg = 0x10000 * i;
> -		groups[i].io_reg = 0x04 + 0x10000 * i;
> -		groups[i].intr_cfg_reg = 0x08 + 0x10000 * i;
> -		groups[i].intr_status_reg = 0x0c + 0x10000 * i;
> -		groups[i].intr_target_reg = 0x08 + 0x10000 * i;
> -
> -		groups[i].mux_bit = 2;
> -		groups[i].pull_bit = 0;
> -		groups[i].drv_bit = 6;
> -		groups[i].oe_bit = 9;
> -		groups[i].in_bit = 0;
> -		groups[i].out_bit = 1;
> -		groups[i].intr_enable_bit = 0;
> -		groups[i].intr_status_bit = 0;
> -		groups[i].intr_target_bit = 5;
> -		groups[i].intr_target_kpss_val = 1;
> -		groups[i].intr_raw_status_bit = 4;
> -		groups[i].intr_polarity_bit = 1;
> -		groups[i].intr_detection_bit = 2;
> -		groups[i].intr_detection_width = 2;
> +	/* Populate the entries that are meant to be exposes as GPIOs. */
> +	for (i = 0; i < avail_gpios; i++) {
> +		unsigned int gpio = gpios[i];
> +
> +		groups[gpio].npins = 1;
> +		snprintf(names[i], NAME_SIZE, "gpio%u", gpio);
> +		pins[gpio].name = names[i];
> +		groups[gpio].name = names[i];
> +
> +		groups[gpio].ctl_reg = 0x10000 * gpio;
> +		groups[gpio].io_reg = 0x04 + 0x10000 * gpio;
> +		groups[gpio].intr_cfg_reg = 0x08 + 0x10000 * gpio;
> +		groups[gpio].intr_status_reg = 0x0c + 0x10000 * gpio;
> +		groups[gpio].intr_target_reg = 0x08 + 0x10000 * gpio;
> +
> +		groups[gpio].mux_bit = 2;
> +		groups[gpio].pull_bit = 0;
> +		groups[gpio].drv_bit = 6;
> +		groups[gpio].oe_bit = 9;
> +		groups[gpio].in_bit = 0;
> +		groups[gpio].out_bit = 1;
> +		groups[gpio].intr_enable_bit = 0;
> +		groups[gpio].intr_status_bit = 0;
> +		groups[gpio].intr_target_bit = 5;
> +		groups[gpio].intr_target_kpss_val = 1;
> +		groups[gpio].intr_raw_status_bit = 4;
> +		groups[gpio].intr_polarity_bit = 1;
> +		groups[gpio].intr_detection_bit = 2;
> +		groups[gpio].intr_detection_width = 2;
>  	}
>
> +	devm_kfree(&pdev->dev, gpios);
> +
>  	qdf2xxx_pinctrl.pins = pins;
>  	qdf2xxx_pinctrl.groups = groups;
>  	qdf2xxx_pinctrl.npins = num_gpios;
> @@ -109,12 +188,6 @@ static int qdf2xxx_pinctrl_probe(struct platform_device *pdev)
>  	return msm_pinctrl_probe(pdev, &qdf2xxx_pinctrl);
>  }
>
> -static const struct acpi_device_id qdf2xxx_acpi_ids[] = {
> -	{"QCOM8001"},
> -	{},
> -};
> -MODULE_DEVICE_TABLE(acpi, qdf2xxx_acpi_ids);
> -
>  static struct platform_driver qdf2xxx_pinctrl_driver = {
>  	.driver = {
>  		.name = "qdf2xxx-pinctrl",
> --
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> Code Aurora Forum, a Linux Foundation Collaborative Project.
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