On 7/08/21 5:12 pm, Michał Mirosław wrote: > On Wed, Aug 04, 2021 at 03:33:56PM +0300, Adrian Hunter wrote: >> On 25/07/21 12:20 pm, Michał Mirosław wrote: >>> Push handling of clock frequency dependence for >>> SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN quirk to the drivers that use it. >> What is the max_clk dependency for, and why push it down? > > I guess this is a workaround for a hardware issue. When I wrote this, > there was only a single user. Now I don't know if the second user got > the limit by accident or just uses the flag not knowing it doesn't work > as the quirk name suggests. IOW this makes it easier to fix in drivers > if the limit is wrong or irrelevant. The dependency doesn't feel like > it belongs to the generic driver anyway. Would you mind reaching out to the authors of the relevant patches and drivers to try to find out the purpose of the max_clk dependency, before we make any changes? > > [...] >>> @@ -318,6 +317,9 @@ static int dwcmshc_rk3568_init(struct sdhci_host *host, struct dwcmshc_priv *dwc >>> sdhci_writel(host, 0, DWCMSHC_EMMC_DLL_TXCLK); >>> sdhci_writel(host, 0, DWCMSHC_EMMC_DLL_STRBIN); >>> >>> + if (sdhci_pltfm_clk_get_max_clock(host) <= 25000000) >>> + host->quirks2 |= SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN; >>> + >>> return 0; >>> } >>> >>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c >>> index 0993f7d0ce8e..cfa314e659bc 100644 >>> --- a/drivers/mmc/host/sdhci.c >>> +++ b/drivers/mmc/host/sdhci.c >>> @@ -1905,8 +1905,7 @@ u16 sdhci_calc_clk(struct sdhci_host *host, unsigned int clock, >>> /* Version 3.00 divisors must be a multiple of 2. */ >>> if (host->max_clk <= clock) { >>> div = 1; >>> - if ((host->quirks2 & SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN) >>> - && host->max_clk <= 25000000) >>> + if (host->quirks2 & SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN) >>> div = 2; >>> } else { >>> for (div = 2; div < SDHCI_MAX_DIV_SPEC_300;