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Subject: Re: [PATCH V5 1/2] ACPI / scan: Support multiple dma windows with
 different offsets
To:     Yicong Yang <yangyicong@huawei.com>,
        Robin Murphy <robin.murphy@arm.com>,
        "Rafael J. Wysocki" <rafael@kernel.org>
Cc:     yangyicong@hisilicon.com, lpieralisi@kernel.org,
        chenhuacai@loongson.cn, guohanjun@huawei.com, sudeep.holla@arm.com,
        lenb@kernel.org, robert.moore@intel.com,
        linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org,
        loongarch@lists.linux.dev, liulongfang <liulongfang@huawei.com>
References: <20220911090635.5559-1-lvjianmin@loongson.cn>
 <20220911090635.5559-2-lvjianmin@loongson.cn>
 <8e9df8ea-06f0-3989-2563-d5dc6b09a062@huawei.com>
 <CAJZ5v0gBBdTxRkE08PO8W+yi1eTkWqzpGLAyMNuzZmqx02EzFA@mail.gmail.com>
 <c7ae3a66-1d24-1014-b63a-8d4af3de42c8@arm.com>
 <7904cd2e-caf5-0073-9889-306ab524d802@huawei.com>
From:   Jianmin Lv <lvjianmin@loongson.cn>
Message-ID: <ded07a34-0cf4-3f76-a538-fb6a9abd6673@loongson.cn>
Date:   Tue, 18 Oct 2022 20:50:38 +0800
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On 2022/10/18 下午8:32, Yicong Yang wrote:
> On 2022/10/18 20:00, Robin Murphy wrote:
>> On 2022-10-18 11:08, Rafael J. Wysocki wrote:
>>> On Tue, Oct 18, 2022 at 11:33 AM Yicong Yang <yangyicong@huawei.com> wrote:
>>>>
>>>> On 2022/9/11 17:06, Jianmin Lv wrote:
>>>>> In DT systems configurations, of_dma_get_range() returns struct
>>>>> bus_dma_region DMA regions; they are used to set-up devices
>>>>> DMA windows with different offset available for translation between DMA
>>>>> address and CPU address.
>>>>>
>>>>> In ACPI systems configuration, acpi_dma_get_range() does not return
>>>>> DMA regions yet and that precludes setting up the dev->dma_range_map
>>>>> pointer and therefore DMA regions with multiple offsets.
>>>>>
>>>>> Update acpi_dma_get_range() to return struct bus_dma_region
>>>>> DMA regions like of_dma_get_range() does.
>>>>>
>>>>> After updating acpi_dma_get_range(), acpi_arch_dma_setup() is changed for
>>>>> ARM64, where the original dma_addr and size are removed as these
>>>>> arguments are now redundant, and pass 0 and U64_MAX for dma_base
>>>>> and size of arch_setup_dma_ops; this is a simplification consistent
>>>>> with what other ACPI architectures also pass to iommu_setup_dma_ops().
>>>>>
>>>>
>>>> Hi,
>>>>
>>>> With this patch we met problem as well. The DMA coherent mask is not set correctly
>>>> for a ehci usb controller and lead to the below calltrace:
>>>>
>>>> [   16.699259] ------------[ cut here ]------------
>>>> [   16.703855] WARNING: CPU: 0 PID: 853 at kernel/dma/mapping.c:499 dma_alloc_attrs+0xc0/0xf0
>>>> [   16.712082] Modules linked in:
>>>> [   16.715124] CPU: 0 PID: 853 Comm: kworker/0:3 Not tainted 6.1.0-rc1-pipe-deadlock+ #5
>>>> [   16.722916] Hardware name: Huawei TaiShan 2280 V2/BC82AMDC, BIOS 2280-V2 CS V5.B211.01 11/10/2021
>>>> [   16.731745] Workqueue: events work_for_cpu_fn
>>>> [   16.736083] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
>>>> [   16.743013] pc : dma_alloc_attrs+0xc0/0xf0
>>>> [   16.747091] lr : dma_pool_alloc+0x11c/0x200
>>>> [   16.751255] sp : ffff80001e46bb50
>>>> [   16.754554] x29: ffff80001e46bb50 x28: 0000000000000000 x27: 0000000000000000
>>>> [   16.761657] x26: ffff80000b33ce18 x25: ffff800009cc6c48 x24: 0000000000000000
>>>> [   16.768759] x23: ffff00208c830918 x22: 0000000000001000 x21: 0000000000000cc0
>>>> [   16.775861] x20: ffff00208ae82080 x19: ffff0020865c40d0 x18: 0000000000000030
>>>> [   16.782964] x17: 626d756e20737562 x16: 2064656e67697373 x15: ffff00208ae82640
>>>> [   16.790066] x14: 0000000000000000 x13: 646e756f72616b72 x12: 6f77204348207379
>>>> [   16.797167] x11: 73706f6e79532067 x10: ffff205f43980000 x9 : ffff80000830b3ac
>>>> [   16.804269] x8 : ffff0020861b1b00 x7 : 0000000000000000 x6 : 0000000000000000
>>>> [   16.811371] x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000cc0
>>>> [   16.818472] x2 : ffff00208c830918 x1 : 0000000000001000 x0 : 0000000000000000
>>>> [   16.825574] Call trace:
>>>> [   16.828009]  dma_alloc_attrs+0xc0/0xf0
>>>> [   16.831741]  dma_pool_alloc+0x11c/0x200
>>>> [   16.835559]  ehci_qh_alloc+0x60/0x12c
>>>> [   16.839207]  ehci_setup+0x18c/0x40c
>>>> [   16.842680]  ehci_pci_setup+0xb8/0x680
>>>> [   16.846412]  usb_add_hcd+0x310/0x5c0
>>>> [   16.849973]  usb_hcd_pci_probe+0x254/0x36c
>>>> [   16.854051]  ehci_pci_probe+0x40/0x60
>>>> [   16.857698]  local_pci_probe+0x48/0xb4
>>>> [   16.861431]  work_for_cpu_fn+0x24/0x40
>>>> [   16.865163]  process_one_work+0x1e0/0x450
>>>> [   16.869155]  worker_thread+0x2cc/0x44c
>>>> [   16.872886]  kthread+0x114/0x120
>>>> [   16.876099]  ret_from_fork+0x10/0x20
>>>> [   16.879657] ---[ end trace 0000000000000000 ]---
>>>>
>>>> After reverting this patch the problem resolved. Tested on the latest 6.1-rc1.
>>>
>>> OK, I'll queue up a revert of this and one more commit depending on it.
>>
>> FWIW it looks like the fix should be as simple as below.
>>
> 
> Looks like it's the case. The change works on my platform, now the ehci probed successfully again
> with no calltrace:
> 
> Tested-by: Yicong Yang <yangyicong@hisilicon.com>
> 
>> Robin.
>>
>> ----->8-----
>> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
>> index 558664d169fc..b6962bff1eae 100644
>> --- a/drivers/acpi/scan.c
>> +++ b/drivers/acpi/scan.c
>> @@ -1509,6 +1509,7 @@ int acpi_dma_get_range(struct device *dev, const struct bus_dma_region **map)
>>               goto out;
>>           }
>>
>> +        *map = r;
>>           list_for_each_entry(rentry, &list, node) {
>>               if (rentry->res->start >= rentry->res->end) {
>>                   kfree(r);
>> @@ -1523,8 +1524,6 @@ int acpi_dma_get_range(struct device *dev, const struct bus_dma_region **map)
>>               r->offset = rentry->offset;
>>               r++;
>>           }
>> -
>> -        *map = r;
>>       }
>>    out:
>>       acpi_dev_free_resource_list(&list);
>>

Ohh, yes, map got a wrong value of r because it has been changed.
Maybe wo can fix it like this:

truct bus_dma_region *r, *orig_r;
...
orig_r = r = kcalloc(ret + 1, sizeof(*r), GFP_KERNEL);
...
*map = orig_r;

>> .