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author | Linus Torvalds <torvalds@linux-foundation.org> | 2013-11-13 23:55:21 +0100 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-11-13 23:55:21 +0100 |
commit | 8ceafbfa91ffbdbb2afaea5c24ccb519ffb8b587 (patch) | |
tree | 98c9ea93362536f1ddd73175b13b7847583350df /arch/arm/mm/dma-mapping.c | |
parent | Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next (diff) | |
parent | ARM: 7805/1: mm: change max*pfn to include the physical offset of memory (diff) | |
download | linux-8ceafbfa91ffbdbb2afaea5c24ccb519ffb8b587.tar.xz linux-8ceafbfa91ffbdbb2afaea5c24ccb519ffb8b587.zip |
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/dma-mapping.c')
-rw-r--r-- | arch/arm/mm/dma-mapping.c | 51 |
1 files changed, 45 insertions, 6 deletions
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 1272ed202dde..644d91f73b00 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; } EXPORT_SYMBOL(dma_supported); |