Re: [PATCH] PCI: Add pci reset quirk for Cavium VNIC

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

On 07/03/17 15:04, Radoslaw Biernacki wrote:
> From: Radoslaw Biernacki <rbiernacki@caviumnetworks.com>
> 
> PCI reset quirk is needed for Cavium Function NIC since it does not
> handle a function level reset.
> This cause problems when VNIC is used from userspace by vfio.
> If application (or VM) does not stop the VNIC queues, HW may cause
> overwrite of memory locations when next application that use it will
> establish new SMMU mappings. More likely HW it will cause SMMU exception,
> when network packet will came before new SMMU mappings will be made.
> 
> Signed-off-by: Radoslaw Biernacki <rbiernacki@caviumnetworks.com>
> Reviewed-by: Sunil Goutham <Sunil.Goutham@cavium.com>
> ---
>  drivers/pci/quirks.c | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 90 insertions(+)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index f754453..f7cdbe5 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -3783,10 +3783,98 @@ static int reset_chelsio_generic_dev(struct pci_dev *dev, int probe)
>  	return 0;
>  }
>  
> +#define CAVIUM_VNIC_QSET_RQ_0_7_CFG		(0x010600)
> +#define CAVIUM_VNIC_QSET_CQ_0_7_CFG		(0x010400)
> +#define CAVIUM_VNIC_QSET_CQ_0_7_CFG2		(0x010408)
> +#define CAVIUM_VNIC_QSET_SQ_0_7_CFG		(0x010800)
> +#define CAVIUM_VNIC_QSET_SQ_0_7_STATUS		(0x010840)
> +#define CAVIUM_VNIC_QSET_RBDR_0_1_CFG		(0x010C00)
> +#define CAVIUM_VNIC_QSET_RBDR_0_1_STATUS0	(0x010C40)
> +
> +#define CAVIUM_VNIC_Q_SHIFT		(18)
> +#define CAVIUM_VNIC_CQ_RESET		(1ULL << 41)
> +#define CAVIUM_VNIC_SQ_RESET		(1ULL << 17)
> +#define CAVIUM_VNIC_RBDR_RESET		(1ULL << 43)
> +#define CAVIUM_VNIC_RBDR_FIFO_STATE_SHIFT (62)
> +
> +/* Poll a register for a specific value */
> +static int cavium_vnic_poll(struct pci_dev *pdev,
> +			    void __iomem *addr, size_t bit_pos,
> +			    size_t bits, u64 val)
> +{
> +	u64 bit_mask;
> +	u64 reg_val;
> +	size_t timeout = 10;
> +
> +	bit_mask = (1ULL << bits) - 1;
> +	bit_mask = (bit_mask << bit_pos);

GENMASK_ULL(bit_pos, bit_pos + bits - 1)? Admittedly it's not an awful
lot tidier :/

> +
> +	while (timeout) {
> +		reg_val = readq(addr);
> +		if (((reg_val & bit_mask) >> bit_pos) == val)
> +			return 0;
> +		usleep_range(1000, 2000);
> +		timeout--;
> +	}

This is essentially an open-coded version of readq_poll_timeout() from
<linux/iopoll.h>, which could be used instead. Doing "val <<= bitpos"
first might help simplify the condition, although since it's only called
with val == 0 it seems that "(reg_val & bit_mask)" would suffice.

Robin.

> +	dev_err(&pdev->dev, "Poll on addr %p failed\n", addr);
> +	return -1;
> +}
> +
> +static int cavium_vnic_reset(struct pci_dev *pdev, int probe)
> +{
> +	size_t qidx;
> +	void __iomem *bar_base;
> +	void __iomem *qset_base;
> +
> +	bar_base = pci_iomap(pdev, 0, 0);
> +	if (!bar_base)
> +		return -ENOMEM;
> +
> +	/* For each of 8 RQ/CQ/SQ (queues) in VF */
> +	for (qidx = 0; qidx < 8; qidx++) {
> +		/* Disable receive queue */
> +		qset_base = bar_base + (qidx << CAVIUM_VNIC_Q_SHIFT);
> +		writeq(0, qset_base + CAVIUM_VNIC_QSET_RQ_0_7_CFG);
> +
> +		/* Disable timer threshold (doesn't get reset upon CQ reset */
> +		writeq(0, qset_base + CAVIUM_VNIC_QSET_CQ_0_7_CFG2);
> +		/* Disable completion queue */
> +		writeq(0, qset_base + CAVIUM_VNIC_QSET_CQ_0_7_CFG);
> +		/* Reset completion queue */
> +		writeq(CAVIUM_VNIC_CQ_RESET,
> +			  qset_base + CAVIUM_VNIC_QSET_CQ_0_7_CFG);
> +
> +		/* Disable send queue */
> +		writeq(0, qset_base + CAVIUM_VNIC_QSET_SQ_0_7_CFG);
> +		/* Reset send queue */
> +		writeq(CAVIUM_VNIC_SQ_RESET,
> +		       qset_base + CAVIUM_VNIC_QSET_SQ_0_7_CFG);
> +	}
> +
> +	/* Reset and disable both RBDR's */
> +	for (qidx = 0; qidx < 2; qidx++) {
> +		qset_base = bar_base +
> +			(qidx << CAVIUM_VNIC_Q_SHIFT);
> +		writeq(CAVIUM_VNIC_RBDR_RESET,
> +		       qset_base + CAVIUM_VNIC_QSET_RBDR_0_1_CFG);
> +		writeq(0, qset_base + CAVIUM_VNIC_QSET_RBDR_0_1_CFG);
> +		if (cavium_vnic_poll(pdev, qset_base +
> +				     CAVIUM_VNIC_QSET_RBDR_0_1_STATUS0,
> +				     CAVIUM_VNIC_RBDR_FIFO_STATE_SHIFT,
> +				     2, 0x00))
> +			dev_err(&pdev->dev, "Timeout on RBDR reset sequence");
> +	}
> +
> +	pci_iounmap(pdev, bar_base);
> +	return 0;
> +}
> +
>  #define PCI_DEVICE_ID_INTEL_82599_SFP_VF   0x10ed
>  #define PCI_DEVICE_ID_INTEL_IVB_M_VGA      0x0156
>  #define PCI_DEVICE_ID_INTEL_IVB_M2_VGA     0x0166
>  
> +#define PCI_DEVICE_ID_CAVIUM_NIC_VF        0xA034
> +
>  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 },
> @@ -3796,6 +3884,8 @@ static int reset_chelsio_generic_dev(struct pci_dev *dev, int probe)
>  		reset_ivb_igd },
>  	{ PCI_VENDOR_ID_CHELSIO, PCI_ANY_ID,
>  		reset_chelsio_generic_dev },
> +	{ PCI_VENDOR_ID_CAVIUM, PCI_DEVICE_ID_CAVIUM_NIC_VF,
> +		cavium_vnic_reset },
>  	{ 0 }
>  };
>  
>