On Wed, 25 Mar 2020 at 15:34, Ludovic Barre <ludovic.barre@xxxxxx> wrote: > > In mmci_write_pwr|clk|datactrlreg functions, if the desired value > is equal to corresponding variable (pwr_reg|clk_reg|datactrl_reg), > the value is not written in the register. > > At probe pwr|clk|datactrl_reg of mmci_host structure are initialized > to 0 (kzalloc of mmc_alloc_host). But they does not necessarily reflect > hardware value of these registers, if they are used while boot level. > This is problematic, if we want to write 0 in these registers. It could be, but I don't see that we ever needs to do that - at least not before we have written some other non-zero values to them (through the helper functions). > > This patch initializes pwr|clk|datactrl_reg variables with their > hardware values while probing. Hmm, so in principle this change seems quite okay, but I am hesitant to pick it up - unless it really addresses a problem that you have observed. The reason is, this change may lead to avoiding to re-write the register with the same value it got during boot - and who knows what is best here. Kind regards Uffe > > Signed-off-by: Ludovic Barre <ludovic.barre@xxxxxx> > --- > drivers/mmc/host/mmci.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c > index 647567def612..f378ae18d5dc 100644 > --- a/drivers/mmc/host/mmci.c > +++ b/drivers/mmc/host/mmci.c > @@ -2085,6 +2085,10 @@ static int mmci_probe(struct amba_device *dev, > else if (plat->ocr_mask) > dev_warn(mmc_dev(mmc), "Platform OCR mask is ignored\n"); > > + host->pwr_reg = readl_relaxed(host->base + MMCIPOWER); > + host->clk_reg = readl_relaxed(host->base + MMCICLOCK); > + host->datactrl_reg = readl_relaxed(host->base + MMCIDATACTRL); > + > /* We support these capabilities. */ > mmc->caps |= MMC_CAP_CMD23; > > -- > 2.17.1 >
