Messages in this thread Patch in this message | | | Subject | Re: [PATCH 2/2] arm: use swiotlb for bounce buffer on LPAE configs | From | Peter Ujfalusi <> | Date | Wed, 8 Jan 2020 16:00:51 +0200 |
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Robin,
On 08/01/2020 14.21, Robin Murphy wrote: > On 08/01/2020 8:28 am, Peter Ujfalusi via iommu wrote: >> Hi Christoph, >> >> On 19/12/2019 17.20, Peter Ujfalusi wrote: >>> Hi Christoph, >>> >>> On 19/12/2019 17.02, Christoph Hellwig wrote: >>>> Hi Peter, >>>> >>>> can you try the patch below (it will need to be split into two): >>> >>> Thank you! >>> >>> Unfortunately it does not help: >>> [ 0.596208] edma: probe of 2700000.edma failed with error -5 >>> [ 0.596626] edma: probe of 2728000.edma failed with error -5 >>> ... >>> [ 2.108602] sdhci-omap 23000000.mmc: Got CD GPIO >>> [ 2.113899] mmc0: Failed to set 32-bit DMA mask. >>> [ 2.118592] mmc0: No suitable DMA available - falling back to PIO >>> [ 2.159038] mmc0: SDHCI controller on 23000000.mmc [23000000.mmc] >>> using PIO >>> [ 2.167531] mmc1: Failed to set 32-bit DMA mask. >>> [ 2.172192] mmc1: No suitable DMA available - falling back to PIO >>> [ 2.213841] mmc1: SDHCI controller on 23100000.mmc [23100000.mmc] >>> using PIO >> >> Do you have idea on how to fix this in a proper way? >> >> IMHO when drivers are setting the dma_mask and coherent_mask the >> dma_pfn_offset should not be applied to the mask at all. >> >> If I understand it correctly for EDMA as example: >> >> I set dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32)); >> since it can only address memory in this range. >> >> It does not matter if dma_pfn_offset is 0 or not 0 (like in k2g, where >> it is 0x780000) the EDMA still can only address within 32 bits. >> >> The dma_pfn_offset will tell us that the memory location's physical >> address is seen by the DMA at (phys_pfn - dma_pfn_offset) -> dma_pfn. >> >> The dma_mask should be checked against the dma_pfn. > > That's exactly what dma_direct_supported() does, though.
Yes, this is my understanding as well.
> What it doesn't > do, AFAICS, is account for weird cases where the DMA zone *starts* way, > way above 32 physical address bits because of an implicit assumption > that *all* devices have a dma_pfn_offset equal to min_low_pfn.
The problem - I think - is that the DMA_BIT_MASK(32) from dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32)) is treated as physical address along the call path so the dma_pfn_offset is applied to it and the check will fail, saying that DMA_BIT_MASK(32) can not be supported.
Fyi, this is what I have gathered on k2g via prints:
dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
Prints inside dma_direct_supported(): sdhci-omap 23000000.mmc: max_pfn: 880000 sdhci-omap 23000000.mmc: min_mask #1: ffffff sdhci-omap 23000000.mmc: min_mask #2: ffffff sdhci-omap 23000000.mmc: dev->dma_pfn_offset: 780000 sdhci-omap 23000000.mmc: PAGE_SHIFT: 12 sdhci-omap 23000000.mmc: __phys_to_dma(dev, min_mask): ff880ffffff sdhci-omap 23000000.mmc: mask: ffffffff
Print in dma_supported() after returning from dma_direct_supported(): sdhci-omap 23000000.mmc: dma_is_direct, ret = 0
sdhci-omap 23100000.mmc: DMA is not supported for the device
keystone-k2g have this in soc0 node: dma-ranges = <0x80000000 0x8 0x00000000 0x80000000>;
DDR starts at 0x8 0000 0000 (8G) and 2G is aliased at 0x8000 0000.
This gives the 0x780000 for dma_pfn_offset for all devices underneath it.
The DMA_BIT_MASK(24) is passed to __phys_to_dma() because CONFIG_ZONE_DMA is enabled.
SWIOTLB is enabled in kconfig.
> I'm not sure how possible it is to cope with that generically.
Me neither, but k2g is failing since v5.3-rc3 and the bisect pointed to this commit.
> > Robin. > >> We can not 'move' the dma_mask with dma_pfn_offset when setting the mask >> since it is not correct. The DMA can access in 32 bits range and we have >> the peripherals under 0x8000 0000. >> >> I might be missing something, but it looks to me that the way we set the >> dma_mask and the coherent_mask is the place where this can be fixed. >> >> Best regards, >> - Péter >> >>> >>> - Péter >>> >>> >>>> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c >>>> index e822af0d9219..30b9c6786ce3 100644 >>>> --- a/arch/arm/mm/dma-mapping.c >>>> +++ b/arch/arm/mm/dma-mapping.c >>>> @@ -221,7 +221,8 @@ EXPORT_SYMBOL(arm_coherent_dma_ops); >>>> static int __dma_supported(struct device *dev, u64 mask, bool warn) >>>> { >>>> - unsigned long max_dma_pfn = min(max_pfn, arm_dma_pfn_limit); >>>> + unsigned long max_dma_pfn = >>>> + min_t(unsigned long, max_pfn, zone_dma_limit >> PAGE_SHIFT); >>>> /* >>>> * Translate the device's DMA mask to a PFN limit. This >>>> diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c >>>> index 3ef204137e73..dd0e169a1bb1 100644 >>>> --- a/arch/arm/mm/init.c >>>> +++ b/arch/arm/mm/init.c >>>> @@ -19,6 +19,7 @@ >>>> #include <linux/gfp.h> >>>> #include <linux/memblock.h> >>>> #include <linux/dma-contiguous.h> >>>> +#include <linux/dma-direct.h> >>>> #include <linux/sizes.h> >>>> #include <linux/stop_machine.h> >>>> #include <linux/swiotlb.h> >>>> @@ -84,15 +85,6 @@ static void __init find_limits(unsigned long >>>> *min, unsigned long *max_low, >>>> phys_addr_t arm_dma_zone_size __read_mostly; >>>> EXPORT_SYMBOL(arm_dma_zone_size); >>>> -/* >>>> - * The DMA mask corresponding to the maximum bus address allocatable >>>> - * using GFP_DMA. The default here places no restriction on DMA >>>> - * allocations. This must be the smallest DMA mask in the system, >>>> - * 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) >>>> { >>>> @@ -108,14 +100,14 @@ static void __init >>>> arm_adjust_dma_zone(unsigned long *size, unsigned long *hole, >>>> void __init setup_dma_zone(const struct machine_desc *mdesc) >>>> { >>>> -#ifdef CONFIG_ZONE_DMA >>>> - if (mdesc->dma_zone_size) { >>>> + if (!IS_ENABLED(CONFIG_ZONE_DMA)) { >>>> + zone_dma_limit = ((phys_addr_t)~0); >>>> + } else if (mdesc->dma_zone_size) { >>>> arm_dma_zone_size = mdesc->dma_zone_size; >>>> - arm_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1; >>>> - } else >>>> - arm_dma_limit = 0xffffffff; >>>> - arm_dma_pfn_limit = arm_dma_limit >> PAGE_SHIFT; >>>> -#endif >>>> + zone_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1; >>>> + } else { >>>> + zone_dma_limit = 0xffffffff; >>>> + } >>>> } >>>> static void __init zone_sizes_init(unsigned long min, unsigned >>>> long max_low, >>>> @@ -279,7 +271,7 @@ void __init arm_memblock_init(const struct >>>> machine_desc *mdesc) >>>> early_init_fdt_scan_reserved_mem(); >>>> /* reserve memory for DMA contiguous allocations */ >>>> - dma_contiguous_reserve(arm_dma_limit); >>>> + dma_contiguous_reserve(zone_dma_limit); >>>> arm_memblock_steal_permitted = false; >>>> memblock_dump_all(); >>>> diff --git a/arch/arm/mm/mm.h b/arch/arm/mm/mm.h >>>> index 88c121ac14b3..7dbd77554273 100644 >>>> --- a/arch/arm/mm/mm.h >>>> +++ b/arch/arm/mm/mm.h >>>> @@ -82,14 +82,6 @@ extern __init void add_static_vm_early(struct >>>> static_vm *svm); >>>> #endif >>>> -#ifdef CONFIG_ZONE_DMA >>>> -extern phys_addr_t arm_dma_limit; >>>> -extern unsigned long arm_dma_pfn_limit; >>>> -#else >>>> -#define arm_dma_limit ((phys_addr_t)~0) >>>> -#define arm_dma_pfn_limit (~0ul >> PAGE_SHIFT) >>>> -#endif >>>> - >>>> extern phys_addr_t arm_lowmem_limit; >>>> void __init bootmem_init(void); >>>> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c >>>> index b65dffdfb201..7a7501acd763 100644 >>>> --- a/arch/arm64/mm/init.c >>>> +++ b/arch/arm64/mm/init.c >>>> @@ -441,7 +441,7 @@ void __init arm64_memblock_init(void) >>>> early_init_fdt_scan_reserved_mem(); >>>> if (IS_ENABLED(CONFIG_ZONE_DMA)) { >>>> - zone_dma_bits = ARM64_ZONE_DMA_BITS; >>>> + zone_dma_limit = DMA_BIT_MASK(ARM64_ZONE_DMA_BITS); >>>> arm64_dma_phys_limit = max_zone_phys(ARM64_ZONE_DMA_BITS); >>>> } >>>> diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c >>>> index 9488b63dfc87..337ace03d3f0 100644 >>>> --- a/arch/powerpc/mm/mem.c >>>> +++ b/arch/powerpc/mm/mem.c >>>> @@ -223,7 +223,7 @@ static int __init mark_nonram_nosave(void) >>>> * everything else. GFP_DMA32 page allocations automatically fall >>>> back to >>>> * ZONE_DMA. >>>> * >>>> - * By using 31-bit unconditionally, we can exploit zone_dma_bits to >>>> inform the >>>> + * By using 31-bit unconditionally, we can exploit zone_dma_limit >>>> to inform the >>>> * generic DMA mapping code. 32-bit only devices (if not handled >>>> by an IOMMU >>>> * anyway) will take a first dip into ZONE_NORMAL and get >>>> otherwise served by >>>> * ZONE_DMA. >>>> @@ -257,18 +257,20 @@ void __init paging_init(void) >>>> printk(KERN_DEBUG "Memory hole size: %ldMB\n", >>>> (long int)((top_of_ram - total_ram) >> 20)); >>>> +#ifdef CONFIG_ZONE_DMA >>>> /* >>>> * Allow 30-bit DMA for very limited Broadcom wifi chips on many >>>> * powerbooks. >>>> */ >>>> - if (IS_ENABLED(CONFIG_PPC32)) >>>> - zone_dma_bits = 30; >>>> - else >>>> - zone_dma_bits = 31; >>>> - >>>> -#ifdef CONFIG_ZONE_DMA >>>> - max_zone_pfns[ZONE_DMA] = min(max_low_pfn, >>>> - 1UL << (zone_dma_bits - PAGE_SHIFT)); >>>> + if (IS_ENABLED(CONFIG_PPC32)) { >>>> + zone_dma_limit = DMA_BIT_MASK(30); >>>> + max_zone_pfns[ZONE_DMA] = min(max_low_pfn, >>>> + 1UL << (30 - PAGE_SHIFT)); >>>> + } else { >>>> + zone_dma_limit = DMA_BIT_MASK(31); >>>> + max_zone_pfns[ZONE_DMA] = min(max_low_pfn, >>>> + 1UL << (31 - PAGE_SHIFT)); >>>> + } >>>> #endif >>>> max_zone_pfns[ZONE_NORMAL] = max_low_pfn; >>>> #ifdef CONFIG_HIGHMEM >>>> diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c >>>> index f0ce22220565..c403f61cb56b 100644 >>>> --- a/arch/s390/mm/init.c >>>> +++ b/arch/s390/mm/init.c >>>> @@ -118,7 +118,7 @@ void __init paging_init(void) >>>> sparse_memory_present_with_active_regions(MAX_NUMNODES); >>>> sparse_init(); >>>> - zone_dma_bits = 31; >>>> + zone_dma_limit = DMA_BIT_MASK(31); >>>> memset(max_zone_pfns, 0, sizeof(max_zone_pfns)); >>>> max_zone_pfns[ZONE_DMA] = PFN_DOWN(MAX_DMA_ADDRESS); >>>> max_zone_pfns[ZONE_NORMAL] = max_low_pfn; >>>> diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h >>>> index 24b8684aa21d..20d56d597506 100644 >>>> --- a/include/linux/dma-direct.h >>>> +++ b/include/linux/dma-direct.h >>>> @@ -6,7 +6,7 @@ >>>> #include <linux/memblock.h> /* for min_low_pfn */ >>>> #include <linux/mem_encrypt.h> >>>> -extern unsigned int zone_dma_bits; >>>> +extern phys_addr_t zone_dma_limit; >>>> #ifdef CONFIG_ARCH_HAS_PHYS_TO_DMA >>>> #include <asm/dma-direct.h> >>>> diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c >>>> index 6af7ae83c4ad..5ea1bed2ba6f 100644 >>>> --- a/kernel/dma/direct.c >>>> +++ b/kernel/dma/direct.c >>>> @@ -21,7 +21,7 @@ >>>> * it for entirely different regions. In that case the arch code >>>> needs to >>>> * override the variable below for dma-direct to work properly. >>>> */ >>>> -unsigned int zone_dma_bits __ro_after_init = 24; >>>> +phys_addr_t zone_dma_limit __ro_after_init = DMA_BIT_MASK(24); >>>> static void report_addr(struct device *dev, dma_addr_t dma_addr, >>>> size_t size) >>>> { >>>> @@ -74,7 +74,7 @@ static gfp_t __dma_direct_optimal_gfp_mask(struct >>>> device *dev, u64 dma_mask, >>>> * Note that GFP_DMA32 and GFP_DMA are no ops without the >>>> corresponding >>>> * zones. >>>> */ >>>> - if (*phys_limit <= DMA_BIT_MASK(zone_dma_bits)) >>>> + if (*phys_limit <= zone_dma_limit) >>>> return GFP_DMA; >>>> if (*phys_limit <= DMA_BIT_MASK(32)) >>>> return GFP_DMA32; >>>> @@ -483,7 +483,7 @@ int dma_direct_supported(struct device *dev, u64 >>>> mask) >>>> u64 min_mask; >>>> if (IS_ENABLED(CONFIG_ZONE_DMA)) >>>> - min_mask = DMA_BIT_MASK(zone_dma_bits); >>>> + min_mask = zone_dma_limit; >>>> else >>>> min_mask = DMA_BIT_MASK(32); >>>> >>>> _______________________________________________ >>>> linux-arm-kernel mailing list >>>> linux-arm-kernel@lists.infradead.org >>>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >>>> >>> >>> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. >>> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki >>> >>> _______________________________________________ >>> linux-arm-kernel mailing list >>> linux-arm-kernel@lists.infradead.org >>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >>> >> >> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. >> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki >> _______________________________________________ >> iommu mailing list >> iommu@lists.linux-foundation.org >> https://lists.linuxfoundation.org/mailman/listinfo/iommu >>
- Péter
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
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