Messages in this thread Patch in this message | | | Date | Fri, 4 Dec 2015 10:37:52 +0000 | From | Brian Starkey <> | Subject | Re: [PATCH] drivers: dma-coherent: use ioremap_wc() for DMA_MEMORY_MAP |
| |
Hi,
Is there anything I can do to help get this merged? It fixes a real problem we have on our arm64 development boards.
From my reading of Documentation/DMA-API.txt it seems like this was the intended behavior in the first place.
Best regards, Brian
On Fri, Nov 20, 2015 at 02:20:26PM +0000, Brian Starkey wrote: >When the DMA_MEMORY_MAP flag is used, memory which can be accessed >directly should be returned, so use ioremap_wc() instead of ioremap(). >Also, ensure that the correct memset operation is used in >dma_alloc_from_coherent() with respect to the region's flags. > >This fixes the below alignment fault on arm64, caused by invalid use >of memset() on Device memory. > > Unhandled fault: alignment fault (0x96000061) at 0xffffff8000380000 > Internal error: : 96000061 [#1] PREEMPT SMP > Modules linked in: hdlcd(+) clk_scpi > CPU: 4 PID: 1355 Comm: systemd-udevd Not tainted 4.4.0-rc1+ #5 > Hardware name: ARM Juno development board (r0) (DT) > task: ffffffc9763eee00 ti: ffffffc9758c4000 task.ti: ffffffc9758c4000 > PC is at __efistub_memset+0x1ac/0x200 > LR is at dma_alloc_from_coherent+0xb0/0x120 > pc : [<ffffffc00030ff2c>] lr : [<ffffffc00042a918>] pstate: 400001c5 > sp : ffffffc9758c79a0 > x29: ffffffc9758c79a0 x28: ffffffc000635cd0 > x27: 0000000000000124 x26: ffffffc000119ef4 > x25: 0000000000010000 x24: 0000000000000140 > x23: ffffffc07e9ac3a8 x22: ffffffc9758c7a58 > x21: ffffffc9758c7a68 x20: 0000000000000004 > x19: ffffffc07e9ac380 x18: 0000000000000001 > x17: 0000007fae1bbba8 x16: ffffffc0001b2d1c > x15: ffffffffffffffff x14: 0ffffffffffffffe > x13: 0000000000000010 x12: ffffff800837ffff > x11: ffffff800837ffff x10: 0000000040000000 > x9 : 0000000000000000 x8 : ffffff8000380000 > x7 : 0000000000000000 x6 : 000000000000003f > x5 : 0000000000000040 x4 : 0000000000000000 > x3 : 0000000000000004 x2 : 000000000000ffc0 > x1 : 0000000000000000 x0 : ffffff8000380000 > >Signed-off-by: Brian Starkey <brian.starkey@arm.com> >Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> >--- > drivers/base/dma-coherent.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > >diff --git a/drivers/base/dma-coherent.c b/drivers/base/dma-coherent.c >index 55b8398..45358d0 100644 >--- a/drivers/base/dma-coherent.c >+++ b/drivers/base/dma-coherent.c >@@ -31,7 +31,10 @@ static int dma_init_coherent_memory(phys_addr_t phys_addr, dma_addr_t device_add > if (!size) > goto out; > >- mem_base = ioremap(phys_addr, size); >+ if (flags & DMA_MEMORY_MAP) >+ mem_base = ioremap_wc(phys_addr, size); >+ else >+ mem_base = ioremap(phys_addr, size); > if (!mem_base) > goto out; > >@@ -181,7 +184,10 @@ int dma_alloc_from_coherent(struct device *dev, ssize_t size, > */ > *dma_handle = mem->device_base + (pageno << PAGE_SHIFT); > *ret = mem->virt_base + (pageno << PAGE_SHIFT); >- memset(*ret, 0, size); >+ if (mem->flags & DMA_MEMORY_MAP) >+ memset(*ret, 0, size); >+ else >+ memset_io(*ret, 0, size); > spin_unlock_irqrestore(&mem->spinlock, flags); > > return 1; >-- >1.7.9.5 > > >_______________________________________________ >linux-arm-kernel mailing list >linux-arm-kernel@lists.infradead.org >http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >
| |