On 25 November 2019 at 10:32 am, Mike Rapoport wrote:
On Mon, Nov 25, 2019 at 08:39:23AM +0100, Christoph Hellwig wrote:
On Sat, Nov 23, 2019 at 12:42:27PM +0100, Christian Zigotzky wrote:
Hello Christoph,
Please find attached the dmesg of your Git kernel.
Thanks. It looks like on your platform the swiotlb buffer isn't
actually addressable based on the bus dma mask limit, which is rather
interesting. swiotlb_init uses memblock_alloc_low to allocate the
buffer, and I'll need some help from Mike and the powerpc maintainers
to figure out how that select where to allocate the buffer from, and
how we can move it to a lower address. My gut feeling would be to try
to do what arm64 does and define a new ARCH_LOW_ADDRESS_LIMIT, preferably
without needing too much arch specific magic.
Presuming the problem is relevant for all CoreNet boards something like
this could work:
diff --git a/arch/powerpc/include/asm/dma.h b/arch/powerpc/include/asm/dma.h
index 1b4f0254868f..7c6cfeeaff52 100644
--- a/arch/powerpc/include/asm/dma.h
+++ b/arch/powerpc/include/asm/dma.h
@@ -347,5 +347,11 @@ extern int isa_dma_bridge_buggy;
#define isa_dma_bridge_buggy (0)
#endif
+#ifdef CONFIG_CORENET_GENERIC
+extern phys_addr_t ppc_dma_phys_limit;
+#define ARCH_LOW_ADDRESS_LIMIT (ppc_dma_phys_limit - 1)
+#endif
+
+
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_DMA_H */
diff --git a/arch/powerpc/platforms/85xx/common.c b/arch/powerpc/platforms/85xx/common.c
index fe0606439b5a..346b436b6d3f 100644
--- a/arch/powerpc/platforms/85xx/common.c
+++ b/arch/powerpc/platforms/85xx/common.c
@@ -126,3 +126,7 @@ void __init mpc85xx_qe_par_io_init(void)
}
}
#endif
+
+#ifdef CONFIG_CORENET_GENERIC
+phys_addr_t ppc_dma_phys_limit = 0xffffffffUL;
+#endif
diff --git a/arch/powerpc/platforms/85xx/corenet_generic.c b/arch/powerpc/platforms/85xx/corenet_generic.c
index 7ee2c6628f64..673bcbdc7c75 100644
--- a/arch/powerpc/platforms/85xx/corenet_generic.c
+++ b/arch/powerpc/platforms/85xx/corenet_generic.c
@@ -64,7 +64,7 @@ void __init corenet_gen_setup_arch(void)
mpc85xx_smp_init();
swiotlb_detect_4g();
-
+ ppc_dma_phys_limit = 0x0fffffffUL;
pr_info("%s board\n", ppc_md.name);
mpc85xx_qe_init();
As a quick hack can you try this patch on top of the tree from Friday?
diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index f491690d54c6..e3f95c362922 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -344,7 +344,7 @@ static inline int memblock_get_region_node(const struct memblock_region *r)
#define MEMBLOCK_LOW_LIMIT 0
#ifndef ARCH_LOW_ADDRESS_LIMIT
-#define ARCH_LOW_ADDRESS_LIMIT 0xffffffffUL
+#define ARCH_LOW_ADDRESS_LIMIT 0x0fffffffUL
#endif
phys_addr_t memblock_phys_alloc_range(phys_addr_t size, phys_addr_t align,
Hello Mike,
Many thanks for your patch! I will test it tomorrow.
Cheers,
Christian
