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 50B5FC19F29 for ; Sat, 6 Aug 2022 06:13:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239375AbiHFGN3 (ORCPT ); Sat, 6 Aug 2022 02:13:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58236 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233595AbiHFGN0 (ORCPT ); Sat, 6 Aug 2022 02:13:26 -0400 Received: from loongson.cn (mail.loongson.cn [114.242.206.163]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id C3556205D2; Fri, 5 Aug 2022 23:13:23 -0700 (PDT) Received: from [10.20.42.22] (unknown [10.20.42.22]) by mail.loongson.cn (Coremail) with SMTP id AQAAf9DxgM94Bu5i2XkIAA--.29591S3; Sat, 06 Aug 2022 14:13:12 +0800 (CST) Subject: Re: [PATCH V2 1/2] ACPI / scan: Support multiple dma windows with different offsets 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> From: Jianmin Lv Message-ID: Date: Sat, 6 Aug 2022 14:13:12 +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: AQAAf9DxgM94Bu5i2XkIAA--.29591S3 X-Coremail-Antispam: 1UD129KBjvAXoW3CF4fAFyUCw1rWF43Aw4UXFb_yoW8GFy7Zo W7Kw13Xr4rJw1jgr4UGr1UJry3Xr1DXrnrtryrGrWayF48JFyUJ348Jry5t3yUJF1rGr18 Gry7JryYqFW7Jr18n29KB7ZKAUJUUUUU529EdanIXcx71UUUUU7v73VFW2AGmfu7bjvjm3 AaLaJ3UjIYCTnIWjp_UUUYh7k0a2IF6w4kM7kC6x804xWl1xkIjI8I6I8E6xAIw20EY4v2 0xvaj40_Wr0E3s1l1IIY67AEw4v_Jr0_Jr4l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rc xSw2x7M28EF7xvwVC0I7IYx2IY67AKxVWUJVWUCwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AK xVW8JVWxJwA2z4x0Y4vEx4A2jsIE14v26r4UJVWxJr1l84ACjcxK6I8E87Iv6xkF7I0E14 v26r4UJVWxJr1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2 j2WlYx0E2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7x kEbVWUJVW8JwACjcxG0xvEwIxGrwCYjI0SjxkI62AI1cAE67vIY487MxkIecxEwVCm-wCF 04k20xvY0x0EwIxGrwCF04k20xvE74AGY7Cv6cx26ryrJr1UJwCFx2IqxVCFs4IE7xkEbV WUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF 67kF1VAFwI0_Jw0_GFylIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42 IY6xIIjxv20xvEc7CjxVAFwI0_Jr0_Gr1lIxAIcVCF04k26cxKx2IYs7xG6rW3Jr0E3s1l IxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxVWUJVW8JbIYCTnIWI evJa73UjIFyTuYvjxUqEoXUUUUU X-CM-SenderInfo: 5oymxthqpl0qxorr0wxvrqhubq/ Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. >> +    } >> + >>       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. >> +    } >>   } >> 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; >>   }