From: Gavin Shan <shangw@linux•vnet.ibm.com>
To: Benjamin Herrenschmidt <benh@kernel•crashing.org>
Cc: linuxppc-dev@lists•ozlabs.org, Gavin Shan <shangw@linux•vnet.ibm.com>
Subject: Re: [PATCH 4/5] powerpc/powernv: Patch MSI EOI handler on P8
Date: Wed, 24 Apr 2013 09:31:36 +0800 [thread overview]
Message-ID: <20130424013136.GB6527@shangw.(null)> (raw)
In-Reply-To: <1366730513.12131.5.camel@pasglop>
On Wed, Apr 24, 2013 at 01:21:53AM +1000, Benjamin Herrenschmidt wrote:
>On Tue, 2013-04-23 at 19:03 +0800, Gavin Shan wrote:
>>
>> +static int pnv_pci_ioda_msi_eoi(struct pnv_phb *phb, unsigned int hw_irq)
>> +{
>> + u8 p_bit = 1, q_bit = 1;
>> + long rc;
>> +
>> + while (p_bit || q_bit) {
>> + rc = opal_pci_get_xive_reissue(phb->opal_id,
>> + hw_irq - phb->msi_base, &p_bit, &q_bit);
>> + if (rc) {
>> + pr_warning("%s: Failed to get P/Q bits of IRQ#%d "
>> + "on PHB#%d, rc=%ld\n", __func__, hw_irq,
>> + phb->hose->global_number, rc);
>> + return -EIO;
>> + }
>> + if (!p_bit && !q_bit)
>> + break;
>> +
>> + rc = opal_pci_set_xive_reissue(phb->opal_id,
>> + hw_irq - phb->msi_base, p_bit, q_bit);
>> + if (rc) {
>> + pr_warning("%s: Failed to clear P/Q (%01d/%01d) of "
>> + "IRQ#%d on PHB#%d, rc=%ld\n", __func__,
>> + p_bit, q_bit, hw_irq,
>> + phb->hose->global_number, rc);
>> + return -EIO;
>> + }
>> + }
>> +
>> + return 0;
>> +}
>
>Can you turn that into a single opal_pci_msi_eoi() ? This means that a
>single MSI will trigger only one OPAL call rather than two which is
>better for performances.
>
Ok. I will add new OPAL API opal_pci_msi_eoi() and use that in next version.
>We will later implement an "optimized" variant using direct MMIO based
>on knowing specifically the HW type but not now.
>
Ok :-)
Thanks,
Gavin
next prev parent reply other threads:[~2013-04-24 1:31 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-23 11:03 [PATCH v2 0/5] powerpc/powernv: PHB3 Support Gavin Shan
2013-04-23 11:03 ` [PATCH 1/5] powerpc/powernv: Supports PHB3 Gavin Shan
2013-04-23 15:19 ` Benjamin Herrenschmidt
2013-04-24 1:29 ` Gavin Shan
2013-04-23 11:03 ` [PATCH 2/5] powerpc/powernv: Retrieve IODA2 tables explicitly Gavin Shan
2013-04-23 11:03 ` [PATCH 3/5] powerpc/powernv: Add option CONFIG_POWERNV_MSI Gavin Shan
2013-04-23 11:03 ` [PATCH 4/5] powerpc/powernv: Patch MSI EOI handler on P8 Gavin Shan
2013-04-23 15:21 ` Benjamin Herrenschmidt
2013-04-24 1:31 ` Gavin Shan [this message]
2013-04-23 11:03 ` [PATCH 5/5] powerpc/powernv: TCE invalidation for PHB3 Gavin Shan
2013-04-23 15:25 ` Benjamin Herrenschmidt
2013-04-24 1:32 ` Gavin Shan
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