Hi,
On 08.08.22 15:55, Sascha Hauer wrote:
> On Mon, Aug 08, 2022 at 03:43:17PM +0200, Ahmad Fatoum wrote:
>> Hello Sascha,
>>
>> On 08.08.22 15:40, Sascha Hauer wrote:
>>> On Mon, Jul 25, 2022 at 01:58:56PM +0200, Ahmad Fatoum wrote:
>>>> In remote labs co-located with other hardware, we've observed card
>>>> detect levers of different boards to sporadically fail to detect
>>>> the card, e.g. because the cable on the usbsdmux was yanked around
>>>> by accident. When this happens, barebox usually boots up normally as
>>>> the card detect is ignored and then Linux waits indefinitely for
>>>> the card-detect to turn active. Add a new config option that can be
>>>> enabled to avoid these issues altogether.
>>>>
>>>> Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
>>>> ---
>>>> v1 -> v2:
>>>> - use early exit instead of if-else
>>>> - don't fail mci_card_probe if of_register_fixup fails
>>>> ---
>>>> drivers/mci/Kconfig | 15 +++++++++++++++
>>>> drivers/mci/mci-core.c | 36 ++++++++++++++++++++++++++++++++----
>>>> 2 files changed, 47 insertions(+), 4 deletions(-)
>>>>
>>>> diff --git a/drivers/mci/Kconfig b/drivers/mci/Kconfig
>>>> index 21d53c0c3f0b..651e59259790 100644
>>>> --- a/drivers/mci/Kconfig
>>>> +++ b/drivers/mci/Kconfig
>>>> @@ -56,6 +56,21 @@ config MCI_MMC_GPP_PARTITIONS
>>>> Note: by default, 'MMC' devices have no 'general purpose partitions',
>>>> it requires a special one-time configuration step to enable them.
>>>>
>>>> +config MCI_BROKEN_CD
>>>> + bool "ignore card-detect pin on boot and in OS"
>>>> + help
>>>> + Say 'y' here to have barebox unconditionally ignore the
>>>> + card-detect pin for its own operation and manipulate the
>>>> + kernel DT, so all detected MCI cards are polled instead
>>>> + of expecting the card detect lever to behave correctly.
>>>> + If you need more fine grained control use of_property
>>>> + in an init script:
>>>> +
>>>> + of_property -fd mmc0 cd-gpios
>>>> + of_property -fs mmc0 broken-cd
>>>> +
>>>> + If unsure, say 'n' here.
>>>> +
>>>> comment "--- MCI host drivers ---"
>>>>
>>>> config MCI_DW
>>>> diff --git a/drivers/mci/mci-core.c b/drivers/mci/mci-core.c
>>>> index 82e2f82f5377..4db2253c3a80 100644
>>>> --- a/drivers/mci/mci-core.c
>>>> +++ b/drivers/mci/mci-core.c
>>>> @@ -1727,6 +1727,27 @@ static int mci_register_partition(struct mci_part *part)
>>>> return 0;
>>>> }
>>>>
>>>> +static int of_broken_cd_fixup(struct device_node *root, void *ctx)
>>>> +{
>>>> + struct device_d *hw_dev = ctx;
>>>> + struct device_node *np;
>>>> + char *name;
>>>> +
>>>> + name = of_get_reproducible_name(hw_dev->device_node);
>>>> + np = of_find_node_by_reproducible_name(root, name);
>>>> + free(name);
>>>> + if (!np) {
>>>> + dev_warn(hw_dev, "Cannot find nodepath %s, cannot fixup\n",
>>>> + hw_dev->device_node->full_name);
>>>> + return -EINVAL;
>>>> + }
>>>> +
>>>> + of_property_write_bool(np, "cd-gpios", false);
>>>> + of_property_write_bool(np, "broken-cd", true);
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> /**
>>>> * Probe an MCI card at the given host interface
>>>> * @param mci MCI device instance
>>>> @@ -1737,10 +1758,13 @@ static int mci_card_probe(struct mci *mci)
>>>> struct mci_host *host = mci->host;
>>>> int i, rc, disknum, ret;
>>>>
>>>> - if (host->card_present && !host->card_present(host) &&
>>>> - !host->non_removable) {
>>>> - dev_err(&mci->dev, "no card inserted\n");
>>>> - return -ENODEV;
>>>> + if (host->card_present && !host->card_present(host) && !host->non_removable) {
>>>> + if (!IS_ENABLED(CONFIG_MCI_BROKEN_CD)) {
>>>> + dev_err(&mci->dev, "no card inserted\n");
>>>> + return -ENODEV;
>>>> + }
>>>> +
>>>> + dev_info(&mci->dev, "no card inserted (ignoring)\n");
>>>> }
>>>>
>>>> ret = regulator_enable(host->supply);
>>>> @@ -1818,6 +1842,10 @@ static int mci_card_probe(struct mci *mci)
>>>> }
>>>> }
>>>>
>>>> + if (IS_ENABLED(CONFIG_MCI_BROKEN_CD) && !host->no_sd &&
>>>> + dev_of_node(host->hw_dev))
>>>> + of_register_fixup(of_broken_cd_fixup, host->hw_dev);
>>>
>>> This fixup is only registered when the card is probed, i.e. when it's
>>> used in barebox. Shouldn't it be registered in mci_register() instead?
>>
>> This is intentional. We only know that cards barebox successfully probed
>> are indeed available.
>
> I don't get this argument. If card detect is broken then why can't we
> let Linux go through the same steps as barebox when barebox hasn't done
> so?
>
> Letting the card work in Linux only when it was previously used in barebox
> is surprising to me.
I'll change it into a device parameter applicable to all cards in v3.
Cheers,
Ahmad
>
> Sascha
>
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