Re: [PATCH v2] mmc: sdhci-pci: Add DMI quirk for missing CD GPIO on Vexia Edu Atla 10 tablet

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

Hi Adrian,

Thank you for the review.

On 11-Nov-24 11:07 AM, Adrian Hunter wrote:
> On 7/11/24 12:00, 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 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 | 38 +++++++++++++++++++++++++++++++
>>  1 file changed, 38 insertions(+)
>>
>> diff --git a/drivers/mmc/host/sdhci-pci-core.c b/drivers/mmc/host/sdhci-pci-core.c
>> index ed45ed0bdafd..9c2bce5e88d9 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>
>> @@ -2054,6 +2055,29 @@ static const struct dev_pm_ops sdhci_pci_pm_ops = {
>>   *                                                                           *
>>  \*****************************************************************************/
>>  
>> +/* DMI quirks for devices with missing or broken CD GPIO info */
>> +static 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),
>> +		{ }
>> +	},
>> +};
>> +
>> +static const struct dmi_system_id sdhci_pci_dmi_cd_gpio_overrides[] = {
>> +	{
>> +		/* 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,
>> +	},
>> +	{ }
>> +};
> 
> Can this be in struct sdhci_pci_fixes?

You mean at a "struct gpiod_lookup_table *cd_gpio_lookup_table" member
to struct sdhci_pci_fixes and then set that for this tablet from say
byt_sd_probe_slot() based on the DMI match (1) ?

Before you ask I just checked and the PCI subsystem ids are generic
(which matches how broken the firmware is on this device in general).

I did consider that, but that would require un-constifying 
"struct sdhci_pci_fixes sdhci_intel_byt_sd" so that byt_sd_probe_slot()
can modify it.

I went with the current approach to be able to keep that struct const.
With your async probing argument from below I think making
byt_sd_probe_slot() set cd_gpio_lookup_table in sdhci_pci_fixes
is a good idea, even if it does require removing the const from
"struct sdhci_pci_fixes sdhci_intel_byt_sd".

1) Before you ask I just checked and the PCI subsystem ids are generic,
which matches how broken the firmware is on this device in general.


>> +
>>  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 +2153,22 @@ 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 = NULL;
>> +		const struct dmi_system_id *dmi_id;
>> +
>> +		dmi_id = dmi_first_match(sdhci_pci_dmi_cd_gpio_overrides);
>> +		if (dmi_id)
>> +			cd_gpio_lookup_table = dmi_id->driver_data;
>> +
>> +		if (cd_gpio_lookup_table)
>> +			gpiod_add_lookup_table(cd_gpio_lookup_table);
> 
> If we were probing asynchronously, gpiod_add_lookup_table() and
> gpiod_remove_lookup_table() could race.

That is a good point.

> I'd suggest making vexia_edu_atla10_cd_gpios const and kmemdup'ing
> and freeing it.
> 
> Add helper functions something like:
> 
> 		cd_gpio_lookup_table = sdhci_pci_add_gpio_lookup_table(chip);
> 		if (IS_ERR(cd_gpio_lookup_table)) {
> 			etc
> 		}
> 
> 		...
> 
> 		sdhci_pci_remove_gpio_lookup_table(cd_gpio_lookup_table);
> 
>> +
>>  		ret = mmc_gpiod_request_cd(host->mmc, "cd", slot->cd_idx,
>>  					   slot->cd_override_level, 0);
>> +
>> +		if (cd_gpio_lookup_table)
>> +			gpiod_remove_lookup_table(cd_gpio_lookup_table);
>> +
>>  		if (ret && ret != -EPROBE_DEFER)
>>  			ret = mmc_gpiod_request_cd(host->mmc, NULL,
>>  						   slot->cd_idx,
> 

That should work yes, I do wonder after adding cd_gpio_lookup_table to
sdhci_pci_fixes only 1 controller will have it set (only the one for
the external slot, not the SDIO wifi and eMMC controllers).
So I think that this race goes away then, avoiding the need to kmemdup ?

Note I'm fine with proceeding either way, just wondering if we cannot
keep things a bit more simple after adding cd_gpio_lookup_table to
sdhci_pci_fixes ?

Regards,

Hans