From mboxrd@z Thu Jan 1 00:00:00 1970 From: balbi@ti.com (Felipe Balbi) Date: Mon, 7 Jul 2014 10:10:24 -0500 Subject: [PATCH] ARM: OMAP2+: l2c: squelch warning dump on power control setting In-Reply-To: <20140707134008.GU3705@n2100.arm.linux.org.uk> References: <20140617131935.GB9070@saruman.home> <20140701194704.GG13396@saruman.home> <20140702081142.GU28884@atomide.com> <20140707104727.GM28884@atomide.com> <20140707104944.GS3705@n2100.arm.linux.org.uk> <20140707110249.GO28884@atomide.com> <53BA8983.3030803@ti.com> <20140707121512.GT3705@n2100.arm.linux.org.uk> <20140707123925.GW28884@atomide.com> <20140707134008.GU3705@n2100.arm.linux.org.uk> Message-ID: <20140707151024.GJ5582@saruman.home> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, On Mon, Jul 07, 2014 at 02:40:08PM +0100, Russell King - ARM Linux wrote: > On Mon, Jul 07, 2014 at 05:39:26AM -0700, Tony Lindgren wrote: > > * Russell King - ARM Linux [140707 05:17]: > > > On Mon, Jul 07, 2014 at 05:20:27PM +0530, Sekhar Nori wrote: > > > > OMAP4430 had L2 cache controller version r2p0 (per the public TRM) which > > > > does not have this register. So unless there is a ROM API that was > > > > introduced after OMAP4430, this would not be there even for other > > > > OMAP4s. Public TRM of OMAP4470 does not indicate an API for this. > > > > > > > > Before creating the patch, I checked with ROM team handling AM437x and > > > > they denied an API to write to this register was present in AM437x ROM. > > > > > > Okay, so why are we trying to write to this register then... > > > > > > Ah, we have a bug in cache-l2x0.c: > > > > > > #define L2X0_CACHE_ID_PART_MASK (0xf << 6) > > > #define L2X0_CACHE_ID_RTL_MASK 0x3f > > > #define L310_CACHE_ID_RTL_R3P0 0x05 > > > > > > unsigned rev = readl_relaxed(base + L2X0_CACHE_ID) & L2X0_CACHE_ID_PART_MASK; > > > > > > if (rev >= L310_CACHE_ID_RTL_R2P0) { > > > ... > > > if (rev >= L310_CACHE_ID_RTL_R3P0) { > > > l2c_write_sec(L310_DYNAMIC_CLK_GATING_EN | L310_STNDBY_MODE_EN, > > > base, L310_POWER_CTRL); > > > > > > So, because we're masking the wrong bits, we end up with these tests > > > always succeeding. > > > > > > So that's a NACK for the original patch, it's the wrong fix. The > > > right fix is to avoid writing this register by fixing the RTL masking. > > > > Okie dokie, dropping the omap specific fix. > > Here's the revision mask fix - with the existing code, the revision checks > are all useless since they would all pass irrespective of the actual > revision. (Had the L2C series been better tested rather than being largely > ignored, this may have been noticed before it was merged...) Anyway, what > isn't clear from Sekhar's message is which revision L2C310 is in the AM437x. > > From: Russell King > Cc: linux-arm-kernel at lists.infradead.org > Subject: [PATCH] ARM: l2c: fix revision checking > > The revision checking in l2c310_enable() was not correct; we were > masking the part number rather than the revision number. Fix this > to use the correct macro. > > Fixes: 4374d64933b1 ("ARM: l2c: add automatic enable of early BRESP") > Signed-off-by: Russell King > --- > arch/arm/mm/cache-l2x0.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c > index 948f12cf6180..0b5068256baf 100644 > --- a/arch/arm/mm/cache-l2x0.c > +++ b/arch/arm/mm/cache-l2x0.c > @@ -732,7 +732,7 @@ static int l2c310_cpu_enable_flz(struct notifier_block *nb, unsigned long act, v > > static void __init l2c310_enable(void __iomem *base, u32 aux, unsigned num_lock) > { > - unsigned rev = readl_relaxed(base + L2X0_CACHE_ID) & L2X0_CACHE_ID_PART_MASK; > + unsigned rev = readl_relaxed(base + L2X0_CACHE_ID) & L2X0_CACHE_ID_RTL_MASK; > bool cortex_a9 = read_cpuid_part() == ARM_CPU_PART_CORTEX_A9; even with this change, l2c still tries to write to power control register, at least on AM437x. Looking a little deeper here, AM437x identifies itself as l2c PL310 r3p3, which should have power control register, but aparentely there's no way to write that register. I'll file a bug to our ROM team, but we will certainly need a way to workaround this inside omap4-common.c -- balbi -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 819 bytes Desc: Digital signature URL: