[PATCH 4/4] powerpc/fsl-pci: Limit ZONE_DMA32 to 2GiB on 64-bit platforms
From: Scott Wood <hidden>
Date: 2014-08-08 23:41:13
Subsystem:
linux for powerpc (32-bit and 64-bit), linux for powerpc embedded ppc85xx, the rest · Maintainers:
Madhavan Srinivasan, Scott Wood, Linus Torvalds
FSL PCI cannot directly address the whole lower 4 GiB due to conflicts with PCICSRBAR and outbound windows. By the time max_direct_dma_addr is set to the precise limit, it will be too late to alter the zone limits, but we should always have at least 2 GiB mapped (unless RAM is smaller than that). Signed-off-by: Scott Wood <redacted> Cc: Shaohui Xie <redacted> --- arch/powerpc/platforms/85xx/corenet_generic.c | 11 +++++++++++ arch/powerpc/platforms/85xx/qemu_e500.c | 10 ++++++++++ 2 files changed, 21 insertions(+)
diff --git a/arch/powerpc/platforms/85xx/corenet_generic.c b/arch/powerpc/platforms/85xx/corenet_generic.c
index d22dd85..c2adb00 100644
--- a/arch/powerpc/platforms/85xx/corenet_generic.c
+++ b/arch/powerpc/platforms/85xx/corenet_generic.c@@ -20,6 +20,7 @@ #include <asm/time.h> #include <asm/machdep.h> #include <asm/pci-bridge.h> +#include <asm/pgtable.h> #include <asm/ppc-pci.h> #include <mm/mmu_decl.h> #include <asm/prom.h>
@@ -67,6 +68,16 @@ void __init corenet_gen_setup_arch(void) swiotlb_detect_4g(); +#if defined(CONFIG_FSL_PCI) && defined(CONFIG_ZONE_DMA32) + /* + * Inbound windows don't cover the full lower 4 GiB + * due to conflicts with PCICSRBAR and outbound windows, + * so limit the DMA32 zone to 2 GiB, to allow consistent + * allocations to succeed. + */ + limit_zone_pfn(ZONE_DMA32, 1UL << (31 - PAGE_SHIFT)); +#endif + pr_info("%s board\n", ppc_md.name); mpc85xx_qe_init();
diff --git a/arch/powerpc/platforms/85xx/qemu_e500.c b/arch/powerpc/platforms/85xx/qemu_e500.c
index 7f26732..8ad2fe6 100644
--- a/arch/powerpc/platforms/85xx/qemu_e500.c
+++ b/arch/powerpc/platforms/85xx/qemu_e500.c@@ -18,6 +18,7 @@ #include <linux/kernel.h> #include <linux/of_fdt.h> #include <asm/machdep.h> +#include <asm/pgtable.h> #include <asm/time.h> #include <asm/udbg.h> #include <asm/mpic.h>
@@ -44,6 +45,15 @@ static void __init qemu_e500_setup_arch(void) fsl_pci_assign_primary(); swiotlb_detect_4g(); +#if defined(CONFIG_FSL_PCI) && defined(CONFIG_ZONE_DMA32) + /* + * Inbound windows don't cover the full lower 4 GiB + * due to conflicts with PCICSRBAR and outbound windows, + * so limit the DMA32 zone to 2 GiB, to allow consistent + * allocations to succeed. + */ + limit_zone_pfn(ZONE_DMA32, 1UL << (31 - PAGE_SHIFT)); +#endif mpc85xx_smp_init(); }
--
1.9.1