Date: Fri, 29 Mar 2013 18:17:51 +0000 (UTC) From: Ian Lepore <ian@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r248904 - head/sys/arm/at91 Message-ID: <201303291817.r2TIHp6s085364@svn.freebsd.org>
next in thread | raw e-mail | index | archive | help
Author: ian Date: Fri Mar 29 18:17:51 2013 New Revision: 248904 URL: http://svnweb.freebsd.org/changeset/base/248904 Log: Redo the workaround for at91rm9200 erratum #26 in a way that doesn't cause a lockup on some rm92 hardware. Modified: head/sys/arm/at91/at91_pmc.c Modified: head/sys/arm/at91/at91_pmc.c ============================================================================== --- head/sys/arm/at91/at91_pmc.c Fri Mar 29 18:10:28 2013 (r248903) +++ head/sys/arm/at91/at91_pmc.c Fri Mar 29 18:17:51 2013 (r248904) @@ -227,23 +227,18 @@ at91_pmc_set_pllb_mode(struct at91_pmc_c struct at91_pmc_softc *sc = pmc_softc; uint32_t value; - if (on) { - on = PMC_IER_LOCKB; - value = pllb_init; - } else - value = 0; + value = on ? pllb_init : 0; - /* Workaround RM9200 Errata #26 */ - if (at91_is_rm92() && - ((value ^ RD4(sc, CKGR_PLLBR)) & 0x03f0ff) != 0) { - WR4(sc, CKGR_PLLBR, value ^ 1); - while ((RD4(sc, PMC_SR) & PMC_IER_LOCKB) != on) + /* + * Only write to the register if the value is changing. Besides being + * good common sense, this works around RM9200 Errata #26 (CKGR_PLL[AB]R + * must not be written with the same value currently in the register). + */ + if (RD4(sc, CKGR_PLLBR) != value) { + WR4(sc, CKGR_PLLBR, value); + while (on && (RD4(sc, PMC_SR) & PMC_IER_LOCKB) != PMC_IER_LOCKB) continue; } - - WR4(sc, CKGR_PLLBR, value); - while ((RD4(sc, PMC_SR) & PMC_IER_LOCKB) != on) - continue; } static void @@ -577,7 +572,6 @@ at91_pmc_init_clock(void) WR4(sc, PMC_SCER, PMC_SCER_MCKUDP); } else WR4(sc, PMC_SCDR, PMC_SCER_UHP_SAM9 | PMC_SCER_UDP_SAM9); - WR4(sc, CKGR_PLLBR, 0); /* * MCK and PCU derive from one of the primary clocks. Initialize
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201303291817.r2TIHp6s085364>