From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 60100C25B06 for ; Sat, 6 Aug 2022 07:23:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230189AbiHFHXs (ORCPT ); Sat, 6 Aug 2022 03:23:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60370 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238396AbiHFHXd (ORCPT ); Sat, 6 Aug 2022 03:23:33 -0400 Received: from loongson.cn (mail.loongson.cn [114.242.206.163]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id BFA1A6152; Sat, 6 Aug 2022 00:22:01 -0700 (PDT) Received: from [10.20.42.22] (unknown [10.20.42.22]) by mail.loongson.cn (Coremail) with SMTP id AQAAf9Ax6syPFu5iIIUIAA--.15253S3; Sat, 06 Aug 2022 15:21:51 +0800 (CST) Subject: Re: [PATCH V2 1/2] ACPI / scan: Support multiple dma windows with different offsets From: Jianmin Lv To: Robin Murphy , lpieralisi@kernel.org, guohanjun@huawei.com, sudeep.holla@arm.com, rafael@kernel.org, lenb@kernel.org, robert.moore@intel.com Cc: linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org References: <1659684674-40612-1-git-send-email-lvjianmin@loongson.cn> <1659684674-40612-2-git-send-email-lvjianmin@loongson.cn> Message-ID: Date: Sat, 6 Aug 2022 15:21:51 +0800 User-Agent: Mozilla/5.0 (X11; Linux loongarch64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-CM-TRANSID: AQAAf9Ax6syPFu5iIIUIAA--.15253S3 X-Coremail-Antispam: 1UD129KBjvAXoW3ur17uw1xWw4xJFykWrWxJFb_yoW8XrWxWo WUKw13Xr4rXw1jgr1UGryUJry3Xr15XrnrJryrGrWakr48AF1UA3y8Jry5tayUJF1rGr1U Gry7Jr1avFW7Jr18n29KB7ZKAUJUUUUU529EdanIXcx71UUUUU7v73VFW2AGmfu7bjvjm3 AaLaJ3UjIYCTnIWjp_UUUY67k0a2IF6w4kM7kC6x804xWl1xkIjI8I6I8E6xAIw20EY4v2 0xvaj40_Wr0E3s1l1IIY67AEw4v_Jr0_Jr4l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rc xSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW5JVW7JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AK xVW8JVWxJwA2z4x0Y4vEx4A2jsIE14v26r4UJVWxJr1l84ACjcxK6I8E87Iv6xkF7I0E14 v26r4UJVWxJr1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2 j2WlYx0E2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7x kEbVWUJVW8JwACjcxG0xvEwIxGrwCYjI0SjxkI62AI1cAE67vIY487MxkIecxEwVCm-wCF 04k20xvY0x0EwIxGrwCF04k20xvE74AGY7Cv6cx26ryrJr1UJwCFx2IqxVCFs4IE7xkEbV WUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF 67kF1VAFwI0_Jw0_GFylIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42 IY6xIIjxv20xvEc7CjxVAFwI0_Jr0_Gr1lIxAIcVCF04k26cxKx2IYs7xG6rW3Jr0E3s1l IxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvf C2KfnxnUUI43ZEXa7IU56c_DUUUUU== X-CM-SenderInfo: 5oymxthqpl0qxorr0wxvrqhubq/ Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 >>> --- >>>   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 >>>   #include >>> -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 >>>   #include >>>   #include >>> +#include >>>   #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; >>>   }