On Tue, Feb 18, 2020 at 09:18:57AM -0800, Guenter Roeck wrote:
> Hi Greg,
>
> please apply the following two patches to v5.4.y and v5.5.y to fix a
> problem when trying to boot various pxa machines from MMC.
>
> d3a5bcb4a17f gpio: add gpiod_toggle_active_low()
> 9073d10b0989 mmc: core: Rework wp-gpio handling
>
> The second patch fixes the problem, the first patch is necessary for the
> second patch to compile.
>
> Background: Commit 9073d10b0989 claims "No functional changes intended".
> However, it does include the following functional code change.
>
> --- a/drivers/mmc/host/pxamci.c
> +++ b/drivers/mmc/host/pxamci.c
> @@ -740,16 +740,16 @@ static int pxamci_probe(struct platform_device *pdev)
> goto out;
> }
>
> + if (!host->pdata->gpio_card_ro_invert)
> + mmc->caps2 |= MMC_CAP2_RO_ACTIVE_HIGH;
> +
> ret = mmc_gpiod_request_ro(mmc, "wp", 0, 0, NULL);
> if (ret && ret != -ENOENT) {
> dev_err(dev, "Failed requesting gpio_ro\n");
> goto out;
> }
> - if (!ret) {
> + if (!ret)
> host->use_ro_gpio = true;
> - mmc->caps2 |= host->pdata->gpio_card_ro_invert ?
> - 0 : MMC_CAP2_RO_ACTIVE_HIGH;
> - }
>
> This _is_ a functional change: Previously, if there was no "ro" gpio
> pin, caps2 was never updated to active-high. This can have the practical
> effect of making the the card read-only, thus preventing the system
> from booting if it was mounted (and expected to be mounted) read-write.
> This is seen when trying to boot "spitz" and similar qemu machines from
> mmc.
>
> I bisected the problem to commit c914a27c92f91 ("mmc: pxamci: Support
> getting GPIO descs for RO and WP), affecting v5.0 and later kernels.
Looks like Sasha just beat me to this, thanks for letting us know about
this.
greg k-h
