From: Christoph Hellwig <hch@lst.de>
[ Upstream commit 9739ab7eda459f0669ec9807e0d9be5020bab88c ]
With the strict dma mask checking introduced with the switch to
the generic DMA direct code common wifi chips on 32-bit powerbooks
stopped working. Add a 30-bit ZONE_DMA to the 32-bit pmac builds
to allow them to reliably allocate dma coherent memory.
Fixes: 65a21b71f948 ("powerpc/dma: remove dma_nommu_dma_supported")
Reported-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Larry Finger <redacted>
Acked-by: Larry Finger <redacted>
Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/include/asm/page.h | 7 +++++++
arch/powerpc/mm/mem.c | 3 ++-
arch/powerpc/platforms/powermac/Kconfig | 1 +
3 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
index ed870468ef6f..d408711d09fb 100644
--- a/arch/powerpc/include/asm/page.h
+++ b/arch/powerpc/include/asm/page.h
@@ -330,6 +330,13 @@ struct vm_area_struct;
#endif /* __ASSEMBLY__ */
#include <asm/slice.h>
+/*
+ * Allow 30-bit DMA for very limited Broadcom wifi chips on many powerbooks.
+ */
+#ifdef CONFIG_PPC32
+#define ARCH_ZONE_DMA_BITS 30
+#else
#define ARCH_ZONE_DMA_BITS 31
+#endif
#endif /* _ASM_POWERPC_PAGE_H */
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index f6787f90e158..b98ce400a889 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -255,7 +255,8 @@ void __init paging_init(void)
(long int)((top_of_ram - total_ram) >> 20));
#ifdef CONFIG_ZONE_DMA
- max_zone_pfns[ZONE_DMA] = min(max_low_pfn, 0x7fffffffUL >> PAGE_SHIFT);
+ max_zone_pfns[ZONE_DMA] = min(max_low_pfn,
+ ((1UL << ARCH_ZONE_DMA_BITS) - 1) >> PAGE_SHIFT);
#endif
max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
#ifdef CONFIG_HIGHMEM
diff --git a/arch/powerpc/platforms/powermac/Kconfig b/arch/powerpc/platforms/powermac/Kconfig
index f834a19ed772..c02d8c503b29 100644
--- a/arch/powerpc/platforms/powermac/Kconfig
+++ b/arch/powerpc/platforms/powermac/Kconfig
@@ -7,6 +7,7 @@ config PPC_PMAC
select PPC_INDIRECT_PCI if PPC32
select PPC_MPC106 if PPC32
select PPC_NATIVE
+ select ZONE_DMA if PPC32
default y
config PPC_PMAC64
--
2.20.1