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![]() R/M classes of cpus can have memory covered by MPU which in turn might configure RAM as Normal i.e. bufferable and cacheable. It breaks dma_alloc_coherent() and friends, since data can stuck in caches now or be buffered. This patch factors out DMA support for NOMMU configuration into separate entity which provides dedicated dma_ops. We have to handle there several cases: - configurations with MMU/MPU setup - configurations without MMU/MPU setup - special case for M-class, since caches and MPU there are optional In general we rely on default DMA area for coherent allocations or/and per-device memory reserves suitable for coherent DMA, so if such regions are set coherent allocations go from there. In case MMU/MPU was not setup we fallback to normal page allocator for DMA memory allocation. In case we run M-class cpus, for configuration without cache support (like Cortex-M3/M4) dma operations are forced to be coherent and wired with dma-noop (such decision is made based on cacheid global variable); however, if caches are detected there and no DMA coherent region is given (either default or per-device), dma is disallowed even MPU is not set - it is because M-class implement system memory map which defines part of address space as Normal memory. Reported-by: Alexandre Torgue <alexandre.torgue@st.com> Reported-by: Andras Szemzo <sza@esh.hu> Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org> Tested-by: Andras Szemzo <sza@esh.hu> Tested-by: Alexandre TORGUE <alexandre.torgue@st.com> Reviewed-by: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Russell King <rmk+kernel@armlinux.org.uk> [hch: removed the dma_supported() implementation that isn't required anymore] Signed-off-by: Christoph Hellwig <hch@lst.de> |
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.. | ||
boot | ||
common | ||
configs | ||
crypto | ||
firmware | ||
include | ||
kernel | ||
kvm | ||
lib | ||
mach-alpine | ||
mach-artpec | ||
mach-asm9260 | ||
mach-aspeed | ||
mach-at91 | ||
mach-axxia | ||
mach-bcm | ||
mach-berlin | ||
mach-clps711x | ||
mach-cns3xxx | ||
mach-davinci | ||
mach-digicolor | ||
mach-dove | ||
mach-ebsa110 | ||
mach-efm32 | ||
mach-ep93xx | ||
mach-exynos | ||
mach-footbridge | ||
mach-gemini | ||
mach-highbank | ||
mach-hisi | ||
mach-imx | ||
mach-integrator | ||
mach-iop13xx | ||
mach-iop32x | ||
mach-iop33x | ||
mach-ixp4xx | ||
mach-keystone | ||
mach-ks8695 | ||
mach-lpc18xx | ||
mach-lpc32xx | ||
mach-mediatek | ||
mach-meson | ||
mach-mmp | ||
mach-moxart | ||
mach-mv78xx0 | ||
mach-mvebu | ||
mach-mxs | ||
mach-netx | ||
mach-nomadik | ||
mach-nspire | ||
mach-omap1 | ||
mach-omap2 | ||
mach-orion5x | ||
mach-oxnas | ||
mach-picoxcell | ||
mach-prima2 | ||
mach-pxa | ||
mach-qcom | ||
mach-realview | ||
mach-rockchip | ||
mach-rpc | ||
mach-s3c24xx | ||
mach-s3c64xx | ||
mach-s5pv210 | ||
mach-sa1100 | ||
mach-shmobile | ||
mach-socfpga | ||
mach-spear | ||
mach-sti | ||
mach-stm32 | ||
mach-sunxi | ||
mach-tango | ||
mach-tegra | ||
mach-u300 | ||
mach-uniphier | ||
mach-ux500 | ||
mach-versatile | ||
mach-vexpress | ||
mach-vt8500 | ||
mach-w90x900 | ||
mach-zx | ||
mach-zynq | ||
mm | ||
net | ||
nwfpe | ||
oprofile | ||
plat-iop | ||
plat-omap | ||
plat-orion | ||
plat-pxa | ||
plat-samsung | ||
plat-versatile | ||
probes | ||
tools | ||
vdso | ||
vfp | ||
xen | ||
Kconfig | ||
Kconfig-nommu | ||
Kconfig.debug | ||
Makefile |