Re: [RFC PATCH] USB: PCI: set 32bit DMA mask for PCI based USB controllers

[John Garry]

On 30/01/2019 07:01, Hanjun Guo wrote:
> From: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
>
> We met an issue that when we update the IORT table to revision D,
> and the kernel update to 4.19, the USB on D06 (ARM64 based server)
> will probe fail:
>
> [   13.495751] CPU: 0 PID: 15 Comm: kworker/0:1 Not tainted 4.19.0-00115-gb2b5200 #5
> [   13.503219] Hardware name: Huawei D06/D06, BIOS Hisilicon D06 UEFI RC0 - V1.09.02 12/25/2018
> [   13.511645] Workqueue: events work_for_cpu_fn
> [   13.515989] pstate: a0c00009 (NzCv daif +PAN +UAO)
> [   13.520767] pc : dma_pool_alloc+0x218/0x270
> [   13.524937] lr : dma_pool_alloc+0xa0/0x270
> [   13.529019] sp : ffff000009e23b20
> [   13.532320] x29: ffff000009e23b20 x28: ffff8027c58ad098
> [   13.537619] x27: 0000000000001000 x26: ffff8027d7a790a8
> [   13.542918] x25: ffff000008fa7000 x24: ffff000009e23bc0
> [   13.548216] x23: 00000000006000c0 x22: ffff8027c58ad010
> [   13.553515] x21: ffff0000097e1000 x20: ffff8027c58ad000
> [   13.558814] x19: ffff8027c58ad080 x18: ffffffffffffffff
> [   13.564112] x17: 0000000000000000 x16: 0000000000007fff
> [   13.569411] x15: ffff0000097e16c8 x14: ffff8027c5d39885
> [   13.574709] x13: ffff8027c5d39884 x12: 0000000000000038
> [   13.580008] x11: 0101010101010101 x10: 7f7f7f7f7f7f7f7f
> [   13.585307] x9 : 0000000000000000 x8 : ffff8027c587c400
> [   13.590605] x7 : 0000000000000000 x6 : 000000000000003f
> [   13.595904] x5 : ffff8027dc5b8000 x4 : ffff8027e09b91e0
> [   13.601202] x3 : 00000000008d2280 x2 : ffff8027c58ad100
> [   13.606501] x1 : 0000000000000028 x0 : 0000000000000000
> [   13.611800] Call trace:
> [   13.614234]  dma_pool_alloc+0x218/0x270
> [   13.617710] ata1: SATA link down (SStatus 0 SControl 300)
> [   13.618059]  ehci_qh_alloc+0x5c/0xf8
> [   13.627002]  ehci_setup+0x17c/0x4b8
> [   13.630478]  ehci_pci_setup+0x18c/0x5b8
> [   13.634301]  usb_add_hcd+0x290/0x7a0
> [   13.637863]  usb_hcd_pci_probe+0x2cc/0x3e8
> [   13.641946]  ehci_pci_probe+0x34/0x48
> [   13.645596]  local_pci_probe+0x3c/0xb0
> [   13.649331]  work_for_cpu_fn+0x18/0x28
> [   13.653067]  process_one_work+0x1e4/0x458
> [   13.657063]  worker_thread+0x228/0x450
> [   13.660798]  kthread+0x12c/0x130
> [   13.664014]  ret_from_fork+0x10/0x18
> [   13.667577] ---[ end trace 6f8757456e2ec456 ]---
>
> It turns out the the IORT revision D introduce the DMA address
> limit size for PCI RC and in commit 5ac65e8c8941 ("ACPI/IORT: Support
> address size limit for root complexes"), will set the DMA mask
> for the RC and that will be inherited by device under the RC.
>
> D06 only enables 1 RC but has EPs with different DMA address sizes,
> for USB it use 32bit DMA, and 64bit for HNS and SAS, so this will
> cause probe failure if we use 64bit DMA for USB controllers.
>
> Set the DMA mask to 32bit for PCI based USB controllers,
> EHCI and OHCI USB controllers are using 32bit DMA address,
> XHCI will set the DMA mask in its probe after the pci probe,
> so it's safe just add dma_coerce_mask_and_coherent() in
> usb_hcd_pci_probe().
>
> Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
> ---
> Hi all,
>
> This is the RFC version, I'm not sure this is the best solution,
> comments are warmly welcomed.
>
> Thanks
> Hanjun
>
>  drivers/usb/core/hcd-pci.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
> index 0343246..a9c33e6 100644
> --- a/drivers/usb/core/hcd-pci.c
> +++ b/drivers/usb/core/hcd-pci.c
> @@ -188,6 +188,10 @@ int usb_hcd_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
>  	if (pci_enable_device(dev) < 0)
>  		return -ENODEV;
>
> +	retval = dma_coerce_mask_and_coherent(&dev->dev, DMA_BIT_MASK(32));
> +	if (retval)
> +		return retval;

Hi Hanjun,

You're missing tidy-up upon failure.

thanks,
John

> +
>  	/*
>  	 * The xHCI driver has its own irq management
>  	 * make sure irq setup is not touched for xhci in generic hcd code