> -----Original Message----- > From: Adrian Hunter [mailto:adrian.hunter@xxxxxxxxx] > Sent: 2020年8月10日 19:26 > To: Bough Chen <haibo.chen@xxxxxxx>; ulf.hansson@xxxxxxxxxx; > linux-mmc@xxxxxxxxxxxxxxx > Cc: dl-linux-imx <linux-imx@xxxxxxx>; shawnguo@xxxxxxxxxx; > s.hauer@xxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx; festevam@xxxxxxxxx > Subject: Re: [PATCH] mmc: host: sdhci-esdhc-imx: reset usdhc before sending > tuning command for manual tuning method > > On 7/08/20 4:50 am, Bough Chen wrote: > > > >> -----Original Message----- > >> From: Adrian Hunter [mailto:adrian.hunter@xxxxxxxxx] > >> Sent: 2020年8月6日 20:11 > >> To: Bough Chen <haibo.chen@xxxxxxx>; ulf.hansson@xxxxxxxxxx; > >> linux-mmc@xxxxxxxxxxxxxxx > >> Cc: dl-linux-imx <linux-imx@xxxxxxx>; shawnguo@xxxxxxxxxx; > >> s.hauer@xxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx; festevam@xxxxxxxxx > >> Subject: Re: [PATCH] mmc: host: sdhci-esdhc-imx: reset usdhc before > >> sending tuning command for manual tuning method > >> > >> On 6/08/20 2:48 pm, haibo.chen@xxxxxxx wrote: > >>> From: Haibo Chen <haibo.chen@xxxxxxx> > >>> > >>> According to IC suggestion, everytime before sending the tuning > >>> command, need to reset the usdhc, so to reset the tuning circuit, to > >>> let every tuning command work well for the manual tuning method. For > >>> standard tuning method, IC already add the reset operation in the logic. > >>> > >>> Signed-off-by: Haibo Chen <haibo.chen@xxxxxxx> > >>> --- > >>> drivers/mmc/host/sdhci-esdhc-imx.c | 1 + > >>> 1 file changed, 1 insertion(+) > >>> > >>> diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c > >>> b/drivers/mmc/host/sdhci-esdhc-imx.c > >>> index a76b4513fbec..e4694eb1b914 100644 > >>> --- a/drivers/mmc/host/sdhci-esdhc-imx.c > >>> +++ b/drivers/mmc/host/sdhci-esdhc-imx.c > >>> @@ -990,6 +990,7 @@ static void esdhc_prepare_tuning(struct > >>> sdhci_host *host, u32 val) > >>> > >>> /* FIXME: delay a bit for card to be ready for next tuning due to errors > */ > >>> mdelay(1); > >>> + sdhci_reset(host, SDHCI_RESET_ALL); > >> > >> Doesn't that reset all registers i.e. the entire ios state? > >> > > > > Hi Adrian, > > For i.MX usdhc, RESET_ALL operation do not impact any register value, it just > reset the internal logic setting. I already verified that. > > Here I just want to set the SDHCI_RESET_ALL bit, but I notice that the API > sdhci_reset() will also touch the host->clock, so I'm not sure whether it is good > enough to use this API directly. Any suggestion? At least, current patch can fix > the manual tuning issue on imx7d/imx8qxp. > > It might be safer to write SDHCI_RESET_ALL directly because, for your case, it > does not have exactly the same semantics as sdhci_reset(). > > It is up to you, but either way, it would be worth adding a comment. > Thanks Adrian, I will write this bit directly and add a comment in the next V2 patch. Best Regards Haibo Chen > > > >>> > >>> reg = readl(host->ioaddr + ESDHC_MIX_CTRL); > >>> reg |= ESDHC_MIX_CTRL_EXE_TUNE | > ESDHC_MIX_CTRL_SMPCLK_SEL | > >>> > >
