[PATCH v2 5/7] mtd: sh_flctl: Use cached register value for FLCMNCR

[Bastian Hecht]

Hello Laurent,

2012/2/18 Laurent Pinchart <laurent.pinchart at ideasonboard.com>:
> Hi Bastian,
>
> Thanks for the patch.
>
> On Saturday 11 February 2012 12:45:03 Bastian Hecht wrote:
>> Instead of reading out the register, use a cached value. This will
>> make way for a proper runtime power management implementation.
>>
>> Signed-off-by: Bastian Hecht <hechtb at gmail.com>
>> ---
>> changelog: I delayed the rtpm patch until the clock code is fixed for
>> board mackerel, so that no "udelay(1);" is needed. Instead I cleaned
>> up the code to use a cached register value. The rtpm code will benefit
>> from it.
>>
>>  drivers/mtd/nand/sh_flctl.c  |   15 +++------------
>>  include/linux/mtd/sh_flctl.h |    1 +
>>  2 files changed, 4 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/mtd/nand/sh_flctl.c b/drivers/mtd/nand/sh_flctl.c
>> index 5c3e71f..1af41fd 100644
>> --- a/drivers/mtd/nand/sh_flctl.c
>> +++ b/drivers/mtd/nand/sh_flctl.c
>> @@ -681,16 +681,13 @@ read_normal_exit:
>>  static void flctl_select_chip(struct mtd_info *mtd, int chipnr)
>>  {
>>       struct sh_flctl *flctl = mtd_to_flctl(mtd);
>> -     uint32_t flcmncr_val = readl(FLCMNCR(flctl));
>>
>>       switch (chipnr) {
>>       case -1:
>> -             flcmncr_val &= ~CE0_ENABLE;
>> -             writel(flcmncr_val, FLCMNCR(flctl));
>> +             writel(flctl->flcmncr_val, FLCMNCR(flctl));
>>               break;
>>       case 0:
>> -             flcmncr_val |= CE0_ENABLE;
>> -             writel(flcmncr_val, FLCMNCR(flctl));
>> +             writel(flctl->flcmncr_val | CE0_ENABLE, FLCMNCR(flctl));
>>               break;
>>       default:
>>               BUG();
>
> Shouldn't you use the cached value in set_cmd_regs() as well ?

Yes that's true. I agree that I should use it on all occasions.

>> @@ -748,11 +745,6 @@ static int flctl_verify_buf(struct mtd_info *mtd, const
>> u_char *buf, int len) return 0;
>>  }
>>
>> -static void flctl_register_init(struct sh_flctl *flctl, unsigned long val)
>> -{
>> -     writel(val, FLCMNCR(flctl));
>> -}
>> -
>>  static int flctl_chip_init_tail(struct mtd_info *mtd)
>>  {
>>       struct sh_flctl *flctl = mtd_to_flctl(mtd);
>> @@ -851,10 +843,9 @@ static int __devinit flctl_probe(struct platform_device
>> *pdev) nand = &flctl->chip;
>>       flctl_mtd->priv = nand;
>>       flctl->pdev = pdev;
>> +     flctl->flcmncr_val = pdata->flcmncr_val;
>>       flctl->hwecc = pdata->has_hwecc;
>>
>> -     flctl_register_init(flctl, pdata->flcmncr_val);
>> -
>>       nand->options = NAND_NO_AUTOINCR;
>>
>>       /* Set address of hardware control function */
>> diff --git a/include/linux/mtd/sh_flctl.h b/include/linux/mtd/sh_flctl.h
>> index e66c393..107fd8a 100644
>> --- a/include/linux/mtd/sh_flctl.h
>> +++ b/include/linux/mtd/sh_flctl.h
>> @@ -132,6 +132,7 @@ struct sh_flctl {
>>       int     erase1_page_addr;       /* page_addr in ERASE1 cmd */
>>       uint32_t erase_ADRCNT;          /* bits of FLCMDCR in ERASE1 cmd */
>>       uint32_t rw_ADRCNT;     /* bits of FLCMDCR in READ WRITE cmd */
>> +     uint32_t flcmncr_val;   /* base value of FLCMNCR */
>>
>>       int     hwecc_cant_correct[4];
> --
> Regards,
>
> Laurent Pinchart

thanks,

 Bastian