On 19/07/23 05:46, Wenchao Chen wrote:
> On Tue, Jul 18, 2023 at 2:13 PM Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
>>
>> On 18/07/23 04:15, Wenchao Chen wrote:
>>> When the card is reset, mmc_card_init() will check if this
>>> card is the previous card by comparing the CID.
>>>
>>> If the firmware is upgraded, the product version may change,
>>> so we remove the product version from the CID check.
>>
>> What is the use-case for this? I would have thought it is safer
>> not to assume anything about the card after the firmware has been
>> upgraded.
>>
> Hi adrian
> Understood, but we have case:
> 1.Before the firmware upgrade
> [T5745@C0] mmc0 oldcard raw->cid[2]: 32691160, raw->cid[3]: d9241800
> PRV=69
> 2.After the firmware upgrade
> [T5745@C0] mmc0 cid[2]: 32011160 cid[3]: d9241800
> PRV=01
> If the PRV is not excluded in the CID check, then the mmc
> initialization will fail after the mmc reset.
> In addition, CRC is excluded because some controllers support
> SDHCI_QUIRK2_RSP_136_HAS_CRC.
I do not know what others are doing in this regard, nor what
circumstances are leading to the re-initialization.
Presumably a clean re-initialization could be done by
unbinding and rebinding the host controller.
>
>>>
>>> Signed-off-by: Wenchao Chen <wenchao.chen@xxxxxxxxxx>
>>> ---
>>> drivers/mmc/core/mmc.c | 18 +++++++++++++++++-
>>> 1 file changed, 17 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
>>> index 89cd48fcec79..32a73378d5c3 100644
>>> --- a/drivers/mmc/core/mmc.c
>>> +++ b/drivers/mmc/core/mmc.c
>>> @@ -32,6 +32,9 @@
>>> #define MIN_CACHE_EN_TIMEOUT_MS 1600
>>> #define CACHE_FLUSH_TIMEOUT_MS 30000 /* 30s */
>>>
>>> +#define MMC_CID_PRV_MASK GENMASK(23, 16)
>>> +#define MMC_CID_CRC_MASK GENMASK(7, 0)
>>> +
>>> static const unsigned int tran_exp[] = {
>>> 10000, 100000, 1000000, 10000000,
>>> 0, 0, 0, 0
>>> @@ -126,6 +129,19 @@ static int mmc_decode_cid(struct mmc_card *card)
>>> return 0;
>>> }
>>>
>>> +static int mmc_check_cid(u32 *cid, u32 *raw_cid)
>>> +{
>>> + /*
>>> + * When comparing CID, we need to remove the product
>>> + * version (Field PRV, offset 55:48) and CRC. Because
>>> + * the product version will change when the firmware
>>> + * is upgraded. Also, the new CRC is different.
>>> + */
>>> + return cid[0] != raw_cid[0] || cid[1] != raw_cid[1] ||
>>> + (cid[2] & ~MMC_CID_PRV_MASK) != (raw_cid[2] & ~MMC_CID_PRV_MASK) ||
>>> + (cid[3] & ~MMC_CID_CRC_MASK) != (raw_cid[3] & ~MMC_CID_CRC_MASK);
>>> +}
>>> +
>>> static void mmc_set_erase_size(struct mmc_card *card)
>>> {
>>> if (card->ext_csd.erase_group_def & 1)
>>> @@ -1640,7 +1656,7 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
>>> goto err;
>>>
>>> if (oldcard) {
>>> - if (memcmp(cid, oldcard->raw_cid, sizeof(cid)) != 0) {
>>> + if (mmc_check_cid(cid, oldcard->raw_cid)) {
>>> pr_debug("%s: Perhaps the card was replaced\n",
>>> mmc_hostname(host));
>>> err = -ENOENT;
>>
