Re: [v2] PCI: Add pci reset quirk for Huawei Intelligent NIC virtual function

[Bjorn Helgaas <helgaas@kernel.org>]

[+cc Alex (please include people who have commented on previous
versions]

Looking for your ack before applying this, Alex.

On Wed, Dec 02, 2020 at 07:34:50PM +0800, Chiqijun wrote:
> When multiple VFs do FLR at the same time, the firmware is
> processed serially, resulting in some VF FLRs being delayed more
> than 100ms, when the virtual machine restarts and the device
> driver is loaded, the firmware is doing the corresponding VF
> FLR, causing the driver to fail to load.
> 
> To solve this problem, add host and firmware status synchronization
> during FLR.
> 
> Signed-off-by: Chiqijun <chiqijun@huawei.com>
> ---
> v2:
>  - Update comments
>  - Use the HINIC_VF_FLR_CAP_BIT_SHIFT and HINIC_VF_FLR_PROC_BIT_SHIFT
>    macro instead of the magic number
> ---
>  drivers/pci/quirks.c | 75 ++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 75 insertions(+)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index f70692ac79c5..c9ad55709d03 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -3912,6 +3912,79 @@ static int delay_250ms_after_flr(struct pci_dev *dev, int probe)
>  	return 0;
>  }
>  
> +#define PCI_DEVICE_ID_HINIC_VF      0x375E
> +#define HINIC_VF_FLR_TYPE           0x1000
> +#define HINIC_VF_FLR_CAP_BIT_SHIFT  6
> +#define HINIC_VF_OP                 0xE80
> +#define HINIC_VF_FLR_PROC_BIT_SHIFT 10
> +#define HINIC_OPERATION_TIMEOUT     15000
> +
> +/* Device-specific reset method for Huawei Intelligent NIC virtual functions */
> +static int reset_hinic_vf_dev(struct pci_dev *pdev, int probe)
> +{
> +	unsigned long timeout;
> +	void __iomem *bar;
> +	u16 old_command;
> +	u32 val;
> +
> +	if (probe)
> +		return 0;
> +
> +	bar = pci_iomap(pdev, 0, 0);
> +	if (!bar)
> +		return -ENOTTY;
> +
> +	pci_read_config_word(pdev, PCI_COMMAND, &old_command);
> +
> +	/*
> +	 * FLR cap bit bit30, FLR processing bit: bit18, to avoid big-endian
> +	 * conversion the big-endian bit6, bit10 is directly operated here.
> +	 *
> +	 * Get and check firmware capabilities.
> +	 */
> +	val = readl(bar + HINIC_VF_FLR_TYPE);
> +	if (!(val & (1UL << HINIC_VF_FLR_CAP_BIT_SHIFT))) {
> +		pci_iounmap(pdev, bar);
> +		return -ENOTTY;
> +	}
> +
> +	/*
> +	 * Set the processing bit for the start of FLR, which will be cleared
> +	 * by the firmware after FLR is completed.
> +	 */
> +	val = readl(bar + HINIC_VF_OP);
> +	val = val | (1UL << HINIC_VF_FLR_PROC_BIT_SHIFT);
> +	writel(val, bar + HINIC_VF_OP);
> +
> +	/* Perform the actual device function reset */
> +	pcie_flr(pdev);
> +
> +	pci_write_config_word(pdev, PCI_COMMAND,
> +			      old_command | PCI_COMMAND_MEMORY);
> +
> +	/* Waiting for device reset complete */
> +	timeout = jiffies + msecs_to_jiffies(HINIC_OPERATION_TIMEOUT);
> +	do {
> +		val = readl(bar + HINIC_VF_OP);
> +		if (!(val & (1UL << HINIC_VF_FLR_PROC_BIT_SHIFT)))
> +			goto reset_complete;
> +		msleep(20);
> +	} while (time_before(jiffies, timeout));
> +
> +	val = readl(bar + HINIC_VF_OP);
> +	if (!(val & (1UL << HINIC_VF_FLR_PROC_BIT_SHIFT)))
> +		goto reset_complete;
> +
> +	pci_warn(pdev, "Reset dev timeout, flr ack reg: %x\n",
> +		 be32_to_cpu(val));
> +
> +reset_complete:
> +	pci_write_config_word(pdev, PCI_COMMAND, old_command);
> +	pci_iounmap(pdev, bar);
> +
> +	return 0;
> +}
> +
>  static const struct pci_dev_reset_methods pci_dev_reset_methods[] = {
>  	{ PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82599_SFP_VF,
>  		 reset_intel_82599_sfp_virtfn },
> @@ -3923,6 +3996,8 @@ static const struct pci_dev_reset_methods pci_dev_reset_methods[] = {
>  	{ PCI_VENDOR_ID_INTEL, 0x0953, delay_250ms_after_flr },
>  	{ PCI_VENDOR_ID_CHELSIO, PCI_ANY_ID,
>  		reset_chelsio_generic_dev },
> +	{ PCI_VENDOR_ID_HUAWEI, PCI_DEVICE_ID_HINIC_VF,
> +		reset_hinic_vf_dev },
>  	{ 0 }
>  };
>  
> -- 
> 2.17.1
>