summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorPaul Burton <paul.burton@imgtec.com>2016-09-02 16:07:10 +0100
committerRalf Baechle <ralf@linux-mips.org>2016-09-29 18:59:49 +0200
commit305723ab439e14debc1d339aa04e835d488b8253 (patch)
treeb9050300d840c04354748bdf580e057cff3629bf
parent1eefcbc89cf3a8e252e5aeb25825594699b47360 (diff)
downloadlinux-sh-305723ab439e14debc1d339aa04e835d488b8253.tar.gz
MIPS: Malta: Fix IOCU disable switch read for MIPS64
Malta boards used with CPU emulators feature a switch to disable use of an IOCU. Software has to check this switch & ignore any present IOCU if the switch is closed. The read used to do this was unsafe for 64 bit kernels, as it simply casted the address 0xbf403000 to a pointer & dereferenced it. Whilst in a 32 bit kernel this would access kseg1, in a 64 bit kernel this attempts to access xuseg & results in an address error exception. Fix by accessing a correctly formed ckseg1 address generated using the CKSEG1ADDR macro. Whilst modifying this code, define the name of the register and the bit we care about within it, which indicates whether PCI DMA is routed to the IOCU or straight to DRAM. The code previously checked that bit 0 was also set, but the least significant 7 bits of the CONFIG_GEN0 register contain the value of the MReqInfo signal provided to the IOCU OCP bus, so singling out bit 0 makes little sense & that part of the check is dropped. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Fixes: b6d92b4a6bdb ("MIPS: Add option to disable software I/O coherency.") Cc: Matt Redfearn <matt.redfearn@imgtec.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Kees Cook <keescook@chromium.org> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/14187/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
-rw-r--r--arch/mips/mti-malta/malta-setup.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/arch/mips/mti-malta/malta-setup.c b/arch/mips/mti-malta/malta-setup.c
index ec5b21678fad..7e7364b0501e 100644
--- a/arch/mips/mti-malta/malta-setup.c
+++ b/arch/mips/mti-malta/malta-setup.c
@@ -39,6 +39,9 @@
#include <linux/console.h>
#endif
+#define ROCIT_CONFIG_GEN0 0x1f403000
+#define ROCIT_CONFIG_GEN0_PCI_IOCU BIT(7)
+
extern void malta_be_init(void);
extern int malta_be_handler(struct pt_regs *regs, int is_fixup);
@@ -107,6 +110,8 @@ static void __init fd_activate(void)
static int __init plat_enable_iocoherency(void)
{
int supported = 0;
+ u32 cfg;
+
if (mips_revision_sconid == MIPS_REVISION_SCON_BONITO) {
if (BONITO_PCICACHECTRL & BONITO_PCICACHECTRL_CPUCOH_PRES) {
BONITO_PCICACHECTRL |= BONITO_PCICACHECTRL_CPUCOH_EN;
@@ -129,7 +134,8 @@ static int __init plat_enable_iocoherency(void)
} else if (mips_cm_numiocu() != 0) {
/* Nothing special needs to be done to enable coherency */
pr_info("CMP IOCU detected\n");
- if ((*(unsigned int *)0xbf403000 & 0x81) != 0x81) {
+ cfg = __raw_readl((u32 *)CKSEG1ADDR(ROCIT_CONFIG_GEN0));
+ if (!(cfg & ROCIT_CONFIG_GEN0_PCI_IOCU)) {
pr_crit("IOCU OPERATION DISABLED BY SWITCH - DEFAULTING TO SW IO COHERENCY\n");
return 0;
}