Re: [PATCH V5 1/2] ACPI / scan: Support multiple dma windows with different offsets

[Robin Murphy <robin.murphy@arm.com>]

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.

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);