Date:   Wed, 8 Mar 2017 15:21:01 +0100
From:   rad <rad@...ihalf.com>
To:     Robin Murphy <robin.murphy@....com>,
        Bjorn Helgaas <bhelgaas@...gle.com>, Sunil.Goutham@...ium.com,
        Robert Richter <robert.richter@...ium.com>,
        David Daney <ddaney@...iumnetworks.com>,
        Robert Richter <rric@...nel.org>,
        David Miller <davem@...emloft.net>
Cc:     Linu.Cherian@...ium.com,
        Radoslaw Biernacki <rbiernacki@...iumnetworks.com>,
        Maciej Czekaj <mjc@...ihalf.com>,
        Tomasz Nowicki <tn@...ihalf.com>, linux-kernel@...r.kernel.org,
        netdev@...r.kernel.org, linux-pci@...r.kernel.org,
        Marcin Wojtas <mw@...ihalf.com>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] PCI: Add pci reset quirk for Cavium VNIC

On 07.03.2017 17:16, Robin Murphy wrote:
> On 07/03/17 15:04, Radoslaw Biernacki wrote:
>> From: Radoslaw Biernacki <rbiernacki@...iumnetworks.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@...iumnetworks.com>
>> Reviewed-by: Sunil Goutham <Sunil.Goutham@...ium.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.

Thanks for pointing this out.
I will try to simplify the condition and use readq_poll_timeout().

>
>> +	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 }
>>   };
>>   
>>

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