Re: [PATCH] dw-mmc: enable trim in eMMC device

[Jaehoon Chung <jh80.chung@samsung.com>]

On 02/10/2014 06:41 PM, Ulf Hansson wrote:
> On 10 February 2014 05:07, Jaehoon Chung <jh80.chung@samsung.com> wrote:
>> Hi,
>>
>> On 02/08/2014 03:39 AM, Puthikorn Voravootivat wrote:
>>> Force host to have erase capacity to enable trim or
>>> discard feature in supported eMMC device.
>>>
>>> Signed-off-by: Puthikorn Voravootivat <puthik@chromium.org>
>>> ---
>>> In mmc_init_queue() before setting up the discard function, mmc driver
>>> will call mmc_can_erase() which will always return 0 because the host
>>> erase capacity is not set anywhere. So to enable discard function, we
>>> need to add erase capacity to the host.
>>>
>>>  drivers/mmc/host/dw_mmc.c | 4 ++++
>>>  1 file changed, 4 insertions(+)
>>>
>>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>>> index 55cd110..f47f1c1 100644
>>> --- a/drivers/mmc/host/dw_mmc.c
>>> +++ b/drivers/mmc/host/dw_mmc.c
>>> @@ -55,6 +55,8 @@
>>>  #define DW_MCI_FREQ_MAX      200000000       /* unit: HZ */
>>>  #define DW_MCI_FREQ_MIN      400000          /* unit: HZ */
>>>
>>> +#define DW_MCI_DEFAULT_CAPS (MMC_CAP_ERASE)
>>> +
>>
>> This define didn't need.
>>
>>>  #ifdef CONFIG_MMC_DW_IDMAC
>>>  #define IDMAC_INT_CLR                (SDMMC_IDMAC_INT_AI | SDMMC_IDMAC_INT_NI | \
>>>                                SDMMC_IDMAC_INT_CES | SDMMC_IDMAC_INT_DU | \
>>> @@ -2371,6 +2373,8 @@ static struct dw_mci_board *dw_mci_parse_dt(struct dw_mci *host)
>>>               return ERR_PTR(-ENOMEM);
>>>       }
>>>
>>> +     pdata->caps |= DW_MCI_DEFAULT_CAPS;
>>> +
>> I didn't want to enable by default. If it's possible, how about using dt-file?
>> Well, if need to enable by default, just use the "pdata->caps |= MMC_CAPS_ERASE;"
> 
> Why not push this one step further; remove MMC_CAPS_ERASE and make it
> default enabled for all hosts?

I think more better that All host used the MMC_CAP_ERASE by default, than this patch.

Best Regards,
Jaehoon Chung

> 
> Kind regards
> Ulf Hansson
> 
>>
>> Best Regards,
>> Jaehoon Chung
>>>       /* find out number of slots supported */
>>>       if (of_property_read_u32(dev->of_node, "num-slots",
>>>                               &pdata->num_slots)) {
>>>
>>
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