From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heiko Schocher Date: Thu, 21 Oct 2010 11:51:57 +0200 Subject: [U-Boot] ELF_RELOC causes strange I-cache issues In-Reply-To: <1287652681-4085-1-git-send-email-albert.aribaud@free.fr> References: <20101020184930.E89F7136320@gemini.denx.de> <4CBF4D17.6020403@free.fr> <20101020205401.39B4D1359B3@gemini.denx.de> <1287652681-4085-1-git-send-email-albert.aribaud@free.fr> Message-ID: <4CC00D3D.2090700@denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hello Albert, Albert Aribaud wrote: > Wolfgang (and others who can/want), > > Please test this patch; it should add a complete barrier to make > sure that all fixups are written to RAM before jumping there, and > that no remnants subsist of the old unfixed code in the instruction > paths. However, I cannot even do basic testing on it as I have > no 1136 board, so I cannot rule out even basic mistakes. > > When this works I'll do a proper [PATCH]. > > Amicalement, > Albert. > > diff --git a/arch/arm/cpu/arm1136/start.S b/arch/arm/cpu/arm1136/start.S > index 8b63192..f49f1de 100644 > --- a/arch/arm/cpu/arm1136/start.S > +++ b/arch/arm/cpu/arm1136/start.S > @@ -257,6 +257,11 @@ fixloop: > add r2, r2, #4 > cmp r2, r3 > bne fixloop > + /* fixups done, cleanup caches if used and prefetch buffer */ > + mov r3, #0 > + mcr p15, 0, r3, c7, c10, 4 /* data synchronization barrier */ > + mcr p15, 0, r3, c7, c5, 0 /* invalidate instruction cache */ > + mcr p15, 0, r3, c7, c5, 4 /* flush prefetch buffer */ > #endif > #endif /* #ifndef CONFIG_SKIP_RELOCATE_UBOOT */ Actually I tried an identically patch, but didn;t help :-( But as reading in the arm manual such a memory barrier should not be bad here ... BTW: I had a fix for this problem, but I completly not understand what it has to do with relocation (if it really is a problem introduced through relocation ...), nor why a flush_cache helps here, because dcache is off and only icache is on ... diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c index f44fc4e..3e326ac 100644 --- a/drivers/usb/host/ehci-hcd.c +++ b/drivers/usb/host/ehci-hcd.c @@ -203,6 +203,8 @@ static inline void ehci_invalidate_dcache(struct QH *qh) static int handshake(uint32_t *ptr, uint32_t mask, uint32_t done, int usec) { uint32_t result; + + flush_cache(0, 0); do { result = ehci_readl(ptr); if (result == ~(uint32_t)0) and the "usb read 80000000 0 1000" command works fine ... Maybe Icache flush dosen;t work because the "ARM1136 Errata 411920 Invalidate Instruction Cache operation can fail" interferes here? bye, Heiko -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany