Re: [PATCH v3] mmc: sdhci-pci: Add DMI quirk for missing CD GPIO on Vexia Edu Atla 10 tablet

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 18-Nov-24 11:10 AM, Adrian Hunter wrote:
> On 16/11/24 13:25, Hans de Goede wrote:
>> Hi Adrian,
>>
>> On 15-Nov-24 8:33 AM, Adrian Hunter wrote:
>>> On 14/11/24 17:56, Hans de Goede wrote:
>>>> The Vexia Edu Atla 10 tablet distributed to schools in the Spanish
>>>> Andalucía region has no ACPI fwnode associated with the SDHCI controller
>>>> for its microsd-slot and thus has no ACPI GPIO resource info.
>>>>
>>>> This causes the following error to be logged and the slot to not work:
>>>> [   10.572113] sdhci-pci 0000:00:12.0: failed to setup card detect gpio
>>>>
>>>> Add a DMI quirk table for providing gpiod_lookup_tables with manually
>>>> provided CD GPIO info and use this DMI table to provide the CD GPIO info
>>>> on this tablet. This fixes the microsd-slot not working.
>>>>
>>>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>>>> ---
>>>> Changes in v3:
>>>> - Add a cd_gpio_override pointer to sdhci_pci_fixes
>>>> - Add sdhci_pci_add_gpio_lookup_table() helper which kmemdup-s a const
>>>>   struct gpiod_lookup_table to avoid races when using async probing
>>>>
>>>> Changes in v2:
>>>> - Make sdhci_pci_dmi_cd_gpio_overrides static const instead of just const
>>>> - Drop duplicate #include <linux/dmi.h> (already there at the end)
>>>> ---
>>>>  drivers/mmc/host/sdhci-pci-core.c | 67 +++++++++++++++++++++++++++++++
>>>>  drivers/mmc/host/sdhci-pci.h      |  1 +
>>>>  2 files changed, 68 insertions(+)
>>>>
>>>> diff --git a/drivers/mmc/host/sdhci-pci-core.c b/drivers/mmc/host/sdhci-pci-core.c
>>>> index ed45ed0bdafd..a2ddbe3d8742 100644
>>>> --- a/drivers/mmc/host/sdhci-pci-core.c
>>>> +++ b/drivers/mmc/host/sdhci-pci-core.c
>>>> @@ -21,6 +21,7 @@
>>>>  #include <linux/io.h>
>>>>  #include <linux/iopoll.h>
>>>>  #include <linux/gpio.h>
>>>> +#include <linux/gpio/machine.h>
>>>>  #include <linux/pm_runtime.h>
>>>>  #include <linux/pm_qos.h>
>>>>  #include <linux/debugfs.h>
>>>> @@ -1235,6 +1236,29 @@ static const struct sdhci_pci_fixes sdhci_intel_byt_sdio = {
>>>>  	.priv_size	= sizeof(struct intel_host),
>>>>  };
>>>>  
>>>> +/* DMI quirks for devices with missing or broken CD GPIO info */
>>>> +static const struct gpiod_lookup_table vexia_edu_atla10_cd_gpios = {
>>>> +	.dev_id = "0000:00:12.0",
>>>> +	.table = {
>>>> +		GPIO_LOOKUP("INT33FC:00", 38, "cd", GPIO_ACTIVE_HIGH),
>>>> +		{ }
>>>> +	},
>>>> +};
>>>
>>> This is good but I feel like we should make it more difficult
>>> to get the size wrong.  Could introduce another struct to hold
>>> the size:
>>>
>>> struct sdhci_pci_gpio_data {
>>> 	const struct gpiod_lookup_table *gpios;
>>> 	size_t size;
>>> };
>>>
>>> static const struct sdhci_pci_gpio_data vexia_edu_atla10_cd_gpio_data = {
>>> 	.gpios = &vexia_edu_atla10_cd_gpios,
>>> 	.size  = sizeof(vexia_edu_atla10_cd_gpios),
>>> };
>>>
>>> So:
>>> 		.driver_data = (void *)&vexia_edu_atla10_cd_gpio_data,
>>> and
>>> 	struct sdhci_pci_gpio_data *data;
>>> 	...
>>> 	data = dmi_id->driver_data;
>>>
>>> 	cd_gpio_lookup_table = kmemdup(data->gpios, data->size, GFP_KERNEL);
>>
>> Interesting idea. But I'm afraid that sizeof(variable-name) on a struct
>> with a flexible array member returns the same as just sizeof(struct struct-name)
>> I added the following debug print to verify this:
>>
>>  static int byt_sd_probe_slot(struct sdhci_pci_slot *slot)
>>  {
>> + pr_info("sizeof(vexia_edu_atla10_cd_gpios) %lu sizeof(struct gpiod_lookup_table) %lu\n",
>> +         sizeof(vexia_edu_atla10_cd_gpios), sizeof(struct gpiod_lookup_table));
>>         byt_probe_slot(slot);
>>         slot->host->mmc->caps |= MMC_CAP_WAIT_WHILE_BUSY |
>>                                  MMC_CAP_AGGRESSIVE_PM | MMC_CAP_CD_WAKE;
>>
>> And that prints:
>>
>> [   10.459681] sizeof(vexia_edu_atla10_cd_gpios) 24 sizeof(struct gpiod_lookup_table) 24
>>
>> So using sizeof(vexia_edu_atla10_cd_gpios) to get the size including the 2
>> flexible array members does not work since sizeof() does not take into
>> account the size of the flexible array members.
> 
> Thanks for spotting that!
> 
> Perhaps we should check the table size then?
> e.g.
> 	struct gpiod_lookup_table *table;
> 	size_t count;
> 
> 	...
> 
> 	table = dmi_id->driver_data;
> 	for (count = 0; table->table[count].key; count++)
> 		;
> 	if (count != 1)
> 		return ERR_PTR(-EINVAL);

That works for me, but why not just use the found count instead of
returning -EINVAL ?

Regards,

Hans



> 
>>>
>>>> +
>>>> +static const struct dmi_system_id sdhci_intel_byt_cd_gpio_override[] = {
>>>> +	{
>>>> +		/* Vexia Edu Atla 10 tablet 9V version */
>>>> +		.matches = {
>>>> +			DMI_MATCH(DMI_BOARD_VENDOR, "AMI Corporation"),
>>>> +			DMI_MATCH(DMI_BOARD_NAME, "Aptio CRB"),
>>>> +			/* Above strings are too generic, also match on BIOS date */
>>>> +			DMI_MATCH(DMI_BIOS_DATE, "08/25/2014"),
>>>> +		},
>>>> +		.driver_data = (void *)&vexia_edu_atla10_cd_gpios,
>>>> +	},
>>>> +	{ }
>>>> +};
>>>> +
>>>>  static const struct sdhci_pci_fixes sdhci_intel_byt_sd = {
>>>>  #ifdef CONFIG_PM_SLEEP
>>>>  	.resume		= byt_resume,
>>>> @@ -1253,6 +1277,7 @@ static const struct sdhci_pci_fixes sdhci_intel_byt_sd = {
>>>>  	.add_host	= byt_add_host,
>>>>  	.remove_slot	= byt_remove_slot,
>>>>  	.ops		= &sdhci_intel_byt_ops,
>>>> +	.cd_gpio_override = sdhci_intel_byt_cd_gpio_override,
>>>>  	.priv_size	= sizeof(struct intel_host),
>>>>  };
>>>>  
>>>> @@ -2054,6 +2079,37 @@ static const struct dev_pm_ops sdhci_pci_pm_ops = {
>>>>   *                                                                           *
>>>>  \*****************************************************************************/
>>>>  
>>>> +static struct gpiod_lookup_table *sdhci_pci_add_gpio_lookup_table(
>>>> +	struct sdhci_pci_chip *chip)
>>>
>>> Let's not line wrap until 100 columns
>>>
>>>> +{
>>>> +	struct gpiod_lookup_table *cd_gpio_lookup_table;
>>>> +	const struct dmi_system_id *dmi_id = NULL;
>>>> +
>>>> +	if (chip->fixes && chip->fixes->cd_gpio_override)
>>>> +		dmi_id = dmi_first_match(chip->fixes->cd_gpio_override);
>>>> +
>>>> +	if (!dmi_id)
>>>> +		return NULL;
>>>> +
>>>> +	cd_gpio_lookup_table = kmemdup(dmi_id->driver_data,
>>>> +				       /* 1 GPIO lookup entry + 1 terminating entry */
>>>> +				       struct_size(cd_gpio_lookup_table, table, 2),
>>>> +				       GFP_KERNEL);
>>>> +	if (!cd_gpio_lookup_table)
>>>> +		return ERR_PTR(-ENOMEM);
>>>> +
>>>> +	gpiod_add_lookup_table(cd_gpio_lookup_table);
>>>> +	return cd_gpio_lookup_table;
>>>> +}
>>>> +
>>>> +static void sdhci_pci_remove_gpio_lookup_table(struct gpiod_lookup_table *lookup_table)
>>>> +{
>>>> +	if (lookup_table) {
>>>> +		gpiod_remove_lookup_table(lookup_table);
>>>> +		kfree(lookup_table);
>>>> +	}
>>>> +}
>>>> +
>>>>  static struct sdhci_pci_slot *sdhci_pci_probe_slot(
>>>>  	struct pci_dev *pdev, struct sdhci_pci_chip *chip, int first_bar,
>>>>  	int slotno)
>>>> @@ -2129,8 +2185,19 @@ static struct sdhci_pci_slot *sdhci_pci_probe_slot(
>>>>  		device_init_wakeup(&pdev->dev, true);
>>>>  
>>>>  	if (slot->cd_idx >= 0) {
>>>> +		struct gpiod_lookup_table *cd_gpio_lookup_table;
>>>> +
>>>> +		cd_gpio_lookup_table = sdhci_pci_add_gpio_lookup_table(chip);
>>>> +		if (IS_ERR(cd_gpio_lookup_table)) {
>>>> +			ret = PTR_ERR(cd_gpio_lookup_table);
>>>> +			goto remove;
>>>> +		}
>>>> +
>>>>  		ret = mmc_gpiod_request_cd(host->mmc, "cd", slot->cd_idx,
>>>>  					   slot->cd_override_level, 0);
>>>> +
>>>> +		sdhci_pci_remove_gpio_lookup_table(cd_gpio_lookup_table);
>>>> +
>>>>  		if (ret && ret != -EPROBE_DEFER)
>>>>  			ret = mmc_gpiod_request_cd(host->mmc, NULL,
>>>>  						   slot->cd_idx,
>>>> diff --git a/drivers/mmc/host/sdhci-pci.h b/drivers/mmc/host/sdhci-pci.h
>>>> index 153704f812ed..4973fa859217 100644
>>>> --- a/drivers/mmc/host/sdhci-pci.h
>>>> +++ b/drivers/mmc/host/sdhci-pci.h
>>>> @@ -156,6 +156,7 @@ struct sdhci_pci_fixes {
>>>>  #endif
>>>>  
>>>>  	const struct sdhci_ops	*ops;
>>>> +	const struct dmi_system_id *cd_gpio_override;
>>>>  	size_t			priv_size;
>>>>  };
>>>>  
>>>
>>
>