path: root/arch/arm/mm
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authorLinus Torvalds <torvalds@linux-foundation.org>2013-11-14 07:55:21 +0900
committerLinus Torvalds <torvalds@linux-foundation.org>2013-11-14 07:55:21 +0900
commit8ceafbfa91ffbdbb2afaea5c24ccb519ffb8b587 (patch)
tree98c9ea93362536f1ddd73175b13b7847583350df /arch/arm/mm
parent42a2d923cc349583ebf6fdd52a7d35e1c2f7e6bd (diff)
parent26ba47b18318abe7dadbe9294a611c0e932651d8 (diff)
Merge branch 'for-linus-dma-masks' of git://git.linaro.org/people/rmk/linux-arm
Pull DMA mask updates from Russell King: "This series cleans up the handling of DMA masks in a lot of drivers, fixing some bugs as we go. Some of the more serious errors include: - drivers which only set their coherent DMA mask if the attempt to set the streaming mask fails. - drivers which test for a NULL dma mask pointer, and then set the dma mask pointer to a location in their module .data section - which will cause problems if the module is reloaded. To counter these, I have introduced two helper functions: - dma_set_mask_and_coherent() takes care of setting both the streaming and coherent masks at the same time, with the correct error handling as specified by the API. - dma_coerce_mask_and_coherent() which resolves the problem of drivers forcefully setting DMA masks. This is more a marker for future work to further clean these locations up - the code which creates the devices really should be initialising these, but to fix that in one go along with this change could potentially be very disruptive. The last thing this series does is prise away some of Linux's addition to "DMA addresses are physical addresses and RAM always starts at zero". We have ARM LPAE systems where all system memory is above 4GB physical, hence having DMA masks interpreted by (eg) the block layers as describing physical addresses in the range 0..DMAMASK fails on these platforms. Santosh Shilimkar addresses this in this series; the patches were copied to the appropriate people multiple times but were ignored. Fixing this also gets rid of some ARM weirdness in the setup of the max*pfn variables, and brings ARM into line with every other Linux architecture as far as those go" * 'for-linus-dma-masks' of git://git.linaro.org/people/rmk/linux-arm: (52 commits) ARM: 7805/1: mm: change max*pfn to include the physical offset of memory ARM: 7797/1: mmc: Use dma_max_pfn(dev) helper for bounce_limit calculations ARM: 7796/1: scsi: Use dma_max_pfn(dev) helper for bounce_limit calculations ARM: 7795/1: mm: dma-mapping: Add dma_max_pfn(dev) helper function ARM: 7794/1: block: Rename parameter dma_mask to max_addr for blk_queue_bounce_limit() ARM: DMA-API: better handing of DMA masks for coherent allocations ARM: 7857/1: dma: imx-sdma: setup dma mask DMA-API: firmware/google/gsmi.c: avoid direct access to DMA masks DMA-API: dcdbas: update DMA mask handing DMA-API: dma: edma.c: no need to explicitly initialize DMA masks DMA-API: usb: musb: use platform_device_register_full() to avoid directly messing with dma masks DMA-API: crypto: remove last references to 'static struct device *dev' DMA-API: crypto: fix ixp4xx crypto platform device support DMA-API: others: use dma_set_coherent_mask() DMA-API: staging: use dma_set_coherent_mask() DMA-API: usb: use new dma_coerce_mask_and_coherent() DMA-API: usb: use dma_set_coherent_mask() DMA-API: parport: parport_pc.c: use dma_coerce_mask_and_coherent() DMA-API: net: octeon: use dma_coerce_mask_and_coherent() DMA-API: net: nxp/lpc_eth: use dma_coerce_mask_and_coherent() ...
Diffstat (limited to 'arch/arm/mm')
3 files changed, 53 insertions, 12 deletions
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 1272ed202dd..644d91f73b0 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -159,7 +159,7 @@ EXPORT_SYMBOL(arm_coherent_dma_ops);
static u64 get_coherent_dma_mask(struct device *dev)
- u64 mask = (u64)arm_dma_limit;
+ u64 mask = (u64)DMA_BIT_MASK(32);
if (dev) {
mask = dev->coherent_dma_mask;
@@ -173,10 +173,30 @@ static u64 get_coherent_dma_mask(struct device *dev)
return 0;
- if ((~mask) & (u64)arm_dma_limit) {
- dev_warn(dev, "coherent DMA mask %#llx is smaller "
- "than system GFP_DMA mask %#llx\n",
- mask, (u64)arm_dma_limit);
+ /*
+ * If the mask allows for more memory than we can address,
+ * and we actually have that much memory, then fail the
+ * allocation.
+ */
+ if (sizeof(mask) != sizeof(dma_addr_t) &&
+ mask > (dma_addr_t)~0 &&
+ dma_to_pfn(dev, ~0) > arm_dma_pfn_limit) {
+ dev_warn(dev, "Coherent DMA mask %#llx is larger than dma_addr_t allows\n",
+ mask);
+ dev_warn(dev, "Driver did not use or check the return value from dma_set_coherent_mask()?\n");
+ return 0;
+ }
+ /*
+ * Now check that the mask, when translated to a PFN,
+ * fits within the allowable addresses which we can
+ * allocate.
+ */
+ if (dma_to_pfn(dev, mask) < arm_dma_pfn_limit) {
+ dev_warn(dev, "Coherent DMA mask %#llx (pfn %#lx-%#lx) covers a smaller range of system memory than the DMA zone pfn 0x0-%#lx\n",
+ mask,
+ dma_to_pfn(dev, 0), dma_to_pfn(dev, mask) + 1,
+ arm_dma_pfn_limit + 1);
return 0;
@@ -1007,8 +1027,27 @@ void arm_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
int dma_supported(struct device *dev, u64 mask)
- if (mask < (u64)arm_dma_limit)
+ unsigned long limit;
+ /*
+ * If the mask allows for more memory than we can address,
+ * and we actually have that much memory, then we must
+ * indicate that DMA to this device is not supported.
+ */
+ if (sizeof(mask) != sizeof(dma_addr_t) &&
+ mask > (dma_addr_t)~0 &&
+ dma_to_pfn(dev, ~0) > arm_dma_pfn_limit)
+ return 0;
+ /*
+ * Translate the device's DMA mask to a PFN limit. This
+ * PFN number includes the page which we can DMA to.
+ */
+ limit = dma_to_pfn(dev, mask);
+ if (limit < arm_dma_pfn_limit)
return 0;
return 1;
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index ca907f805c5..3e8f106ee5f 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -209,6 +209,7 @@ EXPORT_SYMBOL(arm_dma_zone_size);
* so a successful GFP_DMA allocation will always satisfy this.
phys_addr_t arm_dma_limit;
+unsigned long arm_dma_pfn_limit;
static void __init arm_adjust_dma_zone(unsigned long *size, unsigned long *hole,
unsigned long dma_size)
@@ -231,6 +232,7 @@ void __init setup_dma_zone(const struct machine_desc *mdesc)
arm_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1;
} else
arm_dma_limit = 0xffffffff;
+ arm_dma_pfn_limit = arm_dma_limit >> PAGE_SHIFT;
@@ -418,12 +420,10 @@ void __init bootmem_init(void)
* This doesn't seem to be used by the Linux memory manager any
* more, but is used by ll_rw_block. If we can get rid of it, we
* also get rid of some of the stuff above as well.
- *
- * Note: max_low_pfn and max_pfn reflect the number of _pages_ in
- * the system, not the maximum PFN.
- max_low_pfn = max_low - PHYS_PFN_OFFSET;
- max_pfn = max_high - PHYS_PFN_OFFSET;
+ min_low_pfn = min;
+ max_low_pfn = max_low;
+ max_pfn = max_high;
@@ -529,7 +529,7 @@ static inline void free_area_high(unsigned long pfn, unsigned long end)
static void __init free_highpages(void)
- unsigned long max_low = max_low_pfn + PHYS_PFN_OFFSET;
+ unsigned long max_low = max_low_pfn;
struct memblock_region *mem, *res;
/* set highmem page free */
diff --git a/arch/arm/mm/mm.h b/arch/arm/mm/mm.h
index d5a4e9ad8f0..d5a982d15a8 100644
--- a/arch/arm/mm/mm.h
+++ b/arch/arm/mm/mm.h
@@ -81,8 +81,10 @@ extern __init void add_static_vm_early(struct static_vm *svm);
extern phys_addr_t arm_dma_limit;
+extern unsigned long arm_dma_pfn_limit;
#define arm_dma_limit ((phys_addr_t)~0)
+#define arm_dma_pfn_limit (~0ul >> PAGE_SHIFT)
extern phys_addr_t arm_lowmem_limit;