Date: Sun, 2 Jul 2017 17:16:14 -0700 (PDT) From: "Rodney W. Grimes" <freebsd@pdx.rh.CN85.dnsmgr.net> To: Marius Strobl <marius@freebsd.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r320577 - head/sys/dev/sdhci Message-ID: <201707030016.v630GE3Z044006@pdx.rh.CN85.dnsmgr.net> In-Reply-To: <201707021913.v62JD1fh060028@repo.freebsd.org>
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> Author: marius > Date: Sun Jul 2 19:13:01 2017 > New Revision: 320577 > URL: https://svnweb.freebsd.org/changeset/base/320577 > > Log: > Retry up to 20 ms to enable bus power as at least with some Intel ^^^^^^^ > SDHCI/eMMC controllers the first attempt after a D3 to D0 transition, > i. e. when the firmware has put the devices into D3 state before, > can fail. > > Modified: > head/sys/dev/sdhci/sdhci.c > > Modified: head/sys/dev/sdhci/sdhci.c > ============================================================================== > --- head/sys/dev/sdhci/sdhci.c Sun Jul 2 16:20:49 2017 (r320576) > +++ head/sys/dev/sdhci/sdhci.c Sun Jul 2 19:13:01 2017 (r320577) > @@ -366,6 +366,7 @@ sdhci_set_clock(struct sdhci_slot *slot, uint32_t cloc > static void > sdhci_set_power(struct sdhci_slot *slot, u_char power) > { > + int i; > uint8_t pwr; > > if (slot->power == power) > @@ -394,9 +395,20 @@ sdhci_set_power(struct sdhci_slot *slot, u_char power) > break; > } > WR1(slot, SDHCI_POWER_CONTROL, pwr); > - /* Turn on the power. */ > + /* > + * Turn on VDD1 power. Note that at least some Intel controllers can > + * fail to enable bus power on the first try after transiting from D3 > + * to D0, so we give them up to 20 ms. ^^^^^^^ > + */ > pwr |= SDHCI_POWER_ON; > - WR1(slot, SDHCI_POWER_CONTROL, pwr); > + for (i = 0; i < 20; i++) { ^^^ > + WR1(slot, SDHCI_POWER_CONTROL, pwr); > + if (RD1(slot, SDHCI_POWER_CONTROL) & SDHCI_POWER_ON) > + break; > + DELAY(100); ^^^^^ 20 x 100uS == 2mS, not 20ms. Please correct the loop, DELAY or the comments. > + } > + if (!(RD1(slot, SDHCI_POWER_CONTROL) & SDHCI_POWER_ON)) > + slot_printf(slot, "Bus power failed to enable"); > > if (slot->quirks & SDHCI_QUIRK_INTEL_POWER_UP_RESET) { > WR1(slot, SDHCI_POWER_CONTROL, pwr | 0x10); > > -- Rod Grimes rgrimes@freebsd.org
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