Messages in this thread | | | Subject | Re: [PATCH V2 1/2] ACPI / scan: Support multiple dma windows with different offsets | From | Jianmin Lv <> | Date | Sat, 6 Aug 2022 15:21:51 +0800 |
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On 2022/8/6 下午2:13, Jianmin Lv wrote: > > > On 2022/8/5 下午8:46, Robin Murphy wrote: >> On 2022-08-05 08:31, Jianmin Lv wrote: >>> For DT, of_dma_get_range returns bus_dma_region typed dma regions, >>> which makes multiple dma windows with different offset available >>> for translation between dma address and cpu address. >>> >>> But for ACPI, acpi_dma_get_range doesn't return similar dma regions, >>> causing no path for setting dev->dma_range_map conveniently. So the >>> patch changes acpi_dma_get_range and returns bus_dma_region typed >>> dma regions according to of_dma_get_range. >>> >>> After changing acpi_dma_get_range, acpi_arch_dma_setup is changed for >>> ARM64, where original dma_addr and size are removed, and pass 0 and >>> U64_MAX for dma_base and size of arch_setup_dma_ops. >> >> Hmm, I realise the reasoning behind this exists largely in my head, so >> for the benefit of everyone else we should perhaps clarify that these >> arguments are now redundant, so this is a simplification consistent >> with what other ACPI architectures also pass to iommu_setup_dma_ops(). >> > > Ok, I'll add reason of changing it into commit log for everyone else. > > >>> Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn> >>> --- >>> drivers/acpi/arm64/dma.c | 44 >>> +++++++++++++++++++++++++++++++++----------- >>> drivers/acpi/scan.c | 48 >>> ++++++++++++++++++++++++------------------------ >>> include/acpi/acpi_bus.h | 3 +-- >>> include/linux/acpi.h | 7 +++---- >>> 4 files changed, 61 insertions(+), 41 deletions(-) >>> >>> diff --git a/drivers/acpi/arm64/dma.c b/drivers/acpi/arm64/dma.c >>> index f16739a..64a41b2 100644 >>> --- a/drivers/acpi/arm64/dma.c >>> +++ b/drivers/acpi/arm64/dma.c >>> @@ -4,11 +4,12 @@ >>> #include <linux/device.h> >>> #include <linux/dma-direct.h> >>> -void acpi_arch_dma_setup(struct device *dev, u64 *dma_addr, u64 >>> *dma_size) >>> +void acpi_arch_dma_setup(struct device *dev) >>> { >>> int ret; >>> u64 end, mask; >>> - u64 dmaaddr = 0, size = 0, offset = 0; >>> + u64 size = 0; >>> + const struct bus_dma_region *map = NULL; >>> /* >>> * If @dev is expected to be DMA-capable then the bus code that >>> created >>> @@ -26,7 +27,33 @@ void acpi_arch_dma_setup(struct device *dev, u64 >>> *dma_addr, u64 *dma_size) >>> else >>> size = 1ULL << 32; >>> - ret = acpi_dma_get_range(dev, &dmaaddr, &offset, &size); >>> + ret = acpi_dma_get_range(dev, &map); >>> + if (!ret) { >>> + const struct bus_dma_region *r = map; >>> + u64 dma_start, dma_end = 0; >>> + >>> + /* determine the overall bounds of all dma regions */ >>> + for (dma_start = U64_MAX; r->size; r++) { >>> + >>> + /* Take lower and upper limits */ >>> + if (r->dma_start < dma_start) >>> + dma_start = r->dma_start; >> >> dma_start now only serves as an overcomplicated way to tell if the >> list was empty, so we don't need it... > > Ok,thanks. > >> >>> + if (r->dma_start + r->size - 1 > dma_end) >>> + dma_end = r->dma_start + r->size - 1; >>> + } >>> + >>> + if (dma_start >= dma_end) { >>> + dev_dbg(dev, "Invalid DMA regions configuration\n"); >>> + return; >> >> ...but we also don't need this check anway - either there was at least >> one valid resource, so dma_end is now set to something sensible, or >> there were none, in which case the implementation of >> acpi_dma_get_range() here returns success while leaving map == NULL, >> so we've already crashed dereferencing r->size. >> > > Ok, thanks. > > >>> + } >>> + >>> + mask = DMA_BIT_MASK(ilog2(dma_end) + 1); >>> + dev->bus_dma_limit = dma_end; >>> + dev->dma_range_map = map; >>> + dev->coherent_dma_mask = min(dev->coherent_dma_mask, mask); >>> + *dev->dma_mask = min(*dev->dma_mask, mask); >> >> Don't duplicate all this, just set "size = dma_end + 1" so the >> existing code below picks it up. >> > > TBH, I'm not familiar with ARM64's DMA stuff, but from the code here, I > think there are two ways to get dma ranges: acpi_dma_get_range or > iort_dma_get_ranges. > > Before the patch, after obtaining the dmaaddr, offset and size in any > way of the both, the bus_dma_limit, mask and dma_range_map will be > initialized, and dma_range_map is created a *new* one for *both* ways. > > But after changing acpi_dma_get_range, when we are ok to obtain > dma_range_map by acpi_dma_get_range, we'll use it instead of creating a > new one like before. For iort_dma_get_ranges, we have to still create a > new dma_range_map. So, I have to handle separately each way here. > > It seems that it's enough to handle dma_range_map separately, and others > can be still initialized in one place. >
Maybe I got what you mean, I looked into dma_direct_set_offset, which is only meaningful when acpi_dma_get_range return 0 with correct offset and dmaaddr. iort_dma_get_ranges is only used to retrieve size. Right? If so, code here should be:
dev->dma_range_map = map; size = dma_end + 1;
>>> + } >>> + >>> if (ret == -ENODEV) >>> ret = iort_dma_get_ranges(dev, &size); >>> if (!ret) { >>> @@ -34,17 +61,12 @@ void acpi_arch_dma_setup(struct device *dev, u64 >>> *dma_addr, u64 *dma_size) >>> * Limit coherent and dma mask based on size retrieved from >>> * firmware. >>> */ >>> - end = dmaaddr + size - 1; >>> + end = size - 1; >>> mask = DMA_BIT_MASK(ilog2(end) + 1); >>> dev->bus_dma_limit = end; >>> dev->coherent_dma_mask = min(dev->coherent_dma_mask, mask); >>> *dev->dma_mask = min(*dev->dma_mask, mask); >>> - } >>> - *dma_addr = dmaaddr; >>> - *dma_size = size; >>> - >>> - ret = dma_direct_set_offset(dev, dmaaddr + offset, dmaaddr, size); >>> - >>> - dev_dbg(dev, "dma_offset(%#08llx)%s\n", offset, ret ? " failed!" >>> : ""); >>> + ret = dma_direct_set_offset(dev, 0, 0, size); >> >> Don't call this - we're setting dev->dma_range_map now, so it will >> only scream and fail (or do nothing if there's no offset). >> > > Same as above. >
Same, If what I understand is right above, dma_direct_set_offset is should be removed as you suggested.
>>> + } >>> } >>> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c >>> index 762b61f..736517e 100644 >>> --- a/drivers/acpi/scan.c >>> +++ b/drivers/acpi/scan.c >>> @@ -20,6 +20,7 @@ >>> #include <linux/platform_data/x86/apple.h> >>> #include <linux/pgtable.h> >>> #include <linux/crc32.h> >>> +#include <linux/dma-direct.h> >>> #include "internal.h" >>> @@ -1492,15 +1493,15 @@ enum dev_dma_attr acpi_get_dma_attr(struct >>> acpi_device *adev) >>> * >>> * Return 0 on success, < 0 on failure. >>> */ >> >> Don't forget to update the kerneldoc as well. >> > > Ok, thanks. > > >>> -int acpi_dma_get_range(struct device *dev, u64 *dma_addr, u64 *offset, >>> - u64 *size) >>> +int acpi_dma_get_range(struct device *dev, const struct >>> bus_dma_region **map) >>> { >>> struct acpi_device *adev; >>> LIST_HEAD(list); >>> struct resource_entry *rentry; >>> int ret; >>> struct device *dma_dev = dev; >>> - u64 len, dma_start = U64_MAX, dma_end = 0, dma_offset = 0; >>> + int num_ranges = 0; >>> + struct bus_dma_region *r; >>> /* >>> * Walk the device tree chasing an ACPI companion with a _DMA >>> @@ -1525,31 +1526,31 @@ int acpi_dma_get_range(struct device *dev, >>> u64 *dma_addr, u64 *offset, >>> ret = acpi_dev_get_dma_resources(adev, &list); >>> if (ret > 0) { >>> + list_for_each_entry(rentry, &list, node) >>> + num_ranges++; >> >> We already have the number of resources in ret. >> > > Ok, thanks. > > >> Looking at this, I also now wonder if we're doing the right thing if >> the object is present but contains no resources. The spec isn't clear >> whether that's even really valid, but if it is, is it meaningful? It >> seems we'd currently consider an empty object equivalent to no object, >> but if anything it should perhaps be interpreted as the opposite, i.e. >> that no DMA is possible because the bus does not decode any ranges. Is >> anyone more familiar with the intent of the spec here? >> >> Thanks, >> Robin. >> > > According to _DMA of ACPI spec, _DMA is optional, if without it(no _DMA > object configured in DSDT), kernel assumes that any address range placed > on bus by a child device is valid and can be decoded. So I think it is > still legal if _DMA is present and no resources contained in it. I mean > an empty _DMA object equals no _DMA object. But obviously it's not > meaningful for an empty _DMA object, anybody should not pass an empty > _DMA object. > >>> + >>> + r = kcalloc(num_ranges + 1, sizeof(*r), GFP_KERNEL); >>> + if (!r) { >>> + ret = -ENOMEM; >>> + goto out; >>> + } >>> + >>> + *map = r; >>> + >>> list_for_each_entry(rentry, &list, node) { >>> - if (dma_offset && rentry->offset != dma_offset) { >>> + if (rentry->res->start >= rentry->res->end) { >>> ret = -EINVAL; >>> - dev_warn(dma_dev, "Can't handle multiple windows >>> with different offsets\n"); >>> + dev_dbg(dma_dev, "Invalid DMA regions >>> configuration\n"); >>> goto out; >>> } >>> - dma_offset = rentry->offset; >>> - >>> - /* Take lower and upper limits */ >>> - if (rentry->res->start < dma_start) >>> - dma_start = rentry->res->start; >>> - if (rentry->res->end > dma_end) >>> - dma_end = rentry->res->end; >>> - } >>> - if (dma_start >= dma_end) { >>> - ret = -EINVAL; >>> - dev_dbg(dma_dev, "Invalid DMA regions configuration\n"); >>> - goto out; >>> + r->cpu_start = rentry->res->start; >>> + r->dma_start = rentry->res->start - rentry->offset; >>> + r->size = rentry->res->end - rentry->res->start + 1; >>> + r->offset = rentry->offset; >>> + r++; >>> } >>> - *dma_addr = dma_start - dma_offset; >>> - len = dma_end - dma_start; >>> - *size = max(len, len + 1); >>> - *offset = dma_offset; >>> } >>> out: >>> acpi_dev_free_resource_list(&list); >>> @@ -1639,20 +1640,19 @@ int acpi_dma_configure_id(struct device *dev, >>> enum dev_dma_attr attr, >>> const u32 *input_id) >>> { >>> const struct iommu_ops *iommu; >>> - u64 dma_addr = 0, size = 0; >>> if (attr == DEV_DMA_NOT_SUPPORTED) { >>> set_dma_ops(dev, &dma_dummy_ops); >>> return 0; >>> } >>> - acpi_arch_dma_setup(dev, &dma_addr, &size); >>> + acpi_arch_dma_setup(dev); >>> iommu = acpi_iommu_configure_id(dev, input_id); >>> if (PTR_ERR(iommu) == -EPROBE_DEFER) >>> return -EPROBE_DEFER; >>> - arch_setup_dma_ops(dev, dma_addr, size, >>> + arch_setup_dma_ops(dev, 0, U64_MAX, >>> iommu, attr == DEV_DMA_COHERENT); >>> return 0; >>> diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h >>> index 0dc1ea0b..e106073 100644 >>> --- a/include/acpi/acpi_bus.h >>> +++ b/include/acpi/acpi_bus.h >>> @@ -611,8 +611,7 @@ struct acpi_pci_root { >>> int acpi_iommu_fwspec_init(struct device *dev, u32 id, >>> struct fwnode_handle *fwnode, >>> const struct iommu_ops *ops); >>> -int acpi_dma_get_range(struct device *dev, u64 *dma_addr, u64 *offset, >>> - u64 *size); >>> +int acpi_dma_get_range(struct device *dev, const struct >>> bus_dma_region **map); >>> int acpi_dma_configure_id(struct device *dev, enum dev_dma_attr attr, >>> const u32 *input_id); >>> static inline int acpi_dma_configure(struct device *dev, >>> diff --git a/include/linux/acpi.h b/include/linux/acpi.h >>> index 44975c1..34e0545 100644 >>> --- a/include/linux/acpi.h >>> +++ b/include/linux/acpi.h >>> @@ -280,12 +280,12 @@ int acpi_table_parse_madt(enum acpi_madt_type id, >>> #ifdef CONFIG_ARM64 >>> void acpi_numa_gicc_affinity_init(struct acpi_srat_gicc_affinity *pa); >>> -void acpi_arch_dma_setup(struct device *dev, u64 *dma_addr, u64 >>> *dma_size); >>> +void acpi_arch_dma_setup(struct device *dev); >>> #else >>> static inline void >>> acpi_numa_gicc_affinity_init(struct acpi_srat_gicc_affinity *pa) { } >>> static inline void >>> -acpi_arch_dma_setup(struct device *dev, u64 *dma_addr, u64 >>> *dma_size) { } >>> +acpi_arch_dma_setup(struct device *dev) { } >>> #endif >>> int acpi_numa_memory_affinity_init (struct acpi_srat_mem_affinity >>> *ma); >>> @@ -974,8 +974,7 @@ static inline enum dev_dma_attr >>> acpi_get_dma_attr(struct acpi_device *adev) >>> return DEV_DMA_NOT_SUPPORTED; >>> } >>> -static inline int acpi_dma_get_range(struct device *dev, u64 *dma_addr, >>> - u64 *offset, u64 *size) >>> +static inline int acpi_dma_get_range(struct device *dev, const >>> struct bus_dma_region **map) >>> { >>> return -ENODEV; >>> }
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