From mboxrd@z Thu Jan 1 00:00:00 1970 From: grygorii.strashko@ti.com (Grygorii Strashko) Date: Mon, 30 Nov 2015 20:27:33 +0200 Subject: [PATCH] ARM: OMAP4: execute initcall to reserve SRAM for I688 only on OMAP4 In-Reply-To: <1448904431.8275.36.camel@pengutronix.de> References: <1447673117-32719-1-git-send-email-l.stach@pengutronix.de> <5649CB16.2030706@ti.com> <1448904431.8275.36.camel@pengutronix.de> Message-ID: <565C9515.1040600@ti.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 11/30/2015 07:27 PM, Lucas Stach wrote: > Am Montag, den 16.11.2015, 14:24 +0200 schrieb Grygorii Strashko: >> On 11/16/2015 01:25 PM, Lucas Stach wrote: >>> omap_interconnect_sync() is the only user of the SRAM scratch area >>> allocated in the omap4_sram_init initcall. The interconnect sync is >>> used exclusively in the OMAP4 specific WFI implementation, so there >>> is no point in allocating the SRAM scratch on other SoC types. >>> >>> Bail out of the initcall if the kernel is not running on OMAP4 to >>> avoid a confusing warning about being unable to allocate the SRAM >>> needed for I688 handling. >>> >>> Signed-off-by: Lucas Stach >>> Tested-by: Bastian Stender >>> --- >>> arch/arm/mach-omap2/omap4-common.c | 3 +++ >>> 1 file changed, 3 insertions(+) >>> >>> diff --git a/arch/arm/mach-omap2/omap4-common.c b/arch/arm/mach-omap2/omap4-common.c >>> index 949696b6f17b..6db393a30a28 100644 >>> --- a/arch/arm/mach-omap2/omap4-common.c >>> +++ b/arch/arm/mach-omap2/omap4-common.c >>> @@ -131,6 +131,9 @@ static int __init omap4_sram_init(void) >>> struct device_node *np; >>> struct gen_pool *sram_pool; >>> >>> + if (!cpu_is_omap44xx()) >>> + return 0; >> >> This one affects on am43xx also >> > So you are saying this erratum is also present on AM43xx? I wasn't able > to deduce this from the information provided by Richard Woodruff. > "..SOCs using similar chassis components of OMAP4430 time are impacted..." "..But AM335x should be immune from this particular issue..." Advisory 11 Asynchronous Bridge Corruption http://www.ti.com/lit/er/sprz408b/sprz408b.pdf >> >>> + >>> np = of_find_compatible_node(NULL, NULL, "ti,omap4-mpu"); >>> if (!np) >>> pr_warn("%s:Unable to allocate sram needed to handle errata I688\n", >> >> Since all OMAP4+ platforms are now DT based why can't we just return from here silently? >> > If we are unable to allocate the SRAM needed to work around I688 this is > a real error on platforms that expose this erratum, so silently bailing > out at this point may obscure a real issue. > SRAM is not allocated here - It's just check to understand do we need it or not in case of multiplatform build where CONFIG_OMAP_INTERCONNECT_BARRIER will be selected most probably. And if "ti,omap4-mpu" was not found - it just means that this, particular, platform is not affected by i688 errata. If someone misses corresponding node in DT - we can't do nothing :) -- regards, -grygorii