From: Alexander Gordeev <agordeev@redhat.com>
To: Tejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
linux-pci@vger.kernel.org, linux-ide@vger.kernel.org,
Ingo Molnar <mingo@kernel.org>, Joerg Roedel <joro@8bytes.org>,
Jan Beulich <JBeulich@suse.com>,
Bjorn Helgaas <bhelgaas@google.com>
Subject: [PATCH v2 3/4] AHCI: Conserve interrupts with pci_enable_msi_block_part() interface
Date: Wed, 4 Sep 2013 16:17:11 +0200 [thread overview]
Message-ID: <20130904141710.GD8726@dhcp-26-207.brq.redhat.com> (raw)
In-Reply-To: <20130904072256.GA8726@dhcp-26-207.brq.redhat.com>
Make use of the new pci_enable_msi_block_part() interface
and conserve on othewise wasted interrupt resources for 10
of 16 unused MSI vectors on Intel chipsets.
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index db4380d..41f9c08 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1091,26 +1091,39 @@ static inline void ahci_gtf_filter_workaround(struct ata_host *host)
{}
#endif
-int ahci_init_interrupts(struct pci_dev *pdev, struct ahci_host_priv *hpriv)
+static int ahci_get_mrsm(struct ahci_host_priv *hpriv)
+{
+ void __iomem *mmio = hpriv->mmio;
+ u32 ctl = readl(mmio + HOST_CTL);
+
+ return (ctl & HOST_MRSM);
+}
+
+int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
+ struct ahci_host_priv *hpriv)
{
int rc;
- unsigned int maxvec;
+ unsigned int n_msis;
- if (!(hpriv->flags & AHCI_HFLAG_NO_MSI)) {
- rc = pci_enable_msi_block_auto(pdev, &maxvec);
- if (rc > 0) {
- if ((rc == maxvec) || (rc == 1))
- return rc;
- /*
- * Assume that advantage of multipe MSIs is negated,
- * so fallback to single MSI mode to save resources
- */
- pci_disable_msi(pdev);
- if (!pci_enable_msi(pdev))
- return 1;
- }
+ if (hpriv->flags & AHCI_HFLAG_NO_MSI)
+ goto intx;
+
+ for (n_msis = roundup_pow_of_two(n_ports);
+ n_msis <= AHCI_MAX_PORTS; n_msis *= 2) {
+ rc = pci_enable_msi_block_part(pdev, n_ports, n_msis);
+ if (rc < 0)
+ goto intx;
+ if (rc)
+ break;
+ if (!ahci_get_mrsm(hpriv))
+ return n_msis;
+ pci_disable_msi(pdev);
}
+ if (!pci_enable_msi(pdev))
+ return 1;
+
+intx:
pci_intx(pdev, 1);
return 0;
}
@@ -1277,10 +1290,6 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
hpriv->mmio = pcim_iomap_table(pdev)[ahci_pci_bar];
- n_msis = ahci_init_interrupts(pdev, hpriv);
- if (n_msis > 1)
- hpriv->flags |= AHCI_HFLAG_MULTI_MSI;
-
/* save initial config */
ahci_pci_save_initial_config(pdev, hpriv);
@@ -1327,6 +1336,10 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
*/
n_ports = max(ahci_nr_ports(hpriv->cap), fls(hpriv->port_map));
+ n_msis = ahci_init_interrupts(pdev, n_ports, hpriv);
+ if (n_msis > 1)
+ hpriv->flags |= AHCI_HFLAG_MULTI_MSI;
+
host = ata_host_alloc_pinfo(&pdev->dev, ppi, n_ports);
if (!host)
return -ENOMEM;
diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index 1145637..19bc846 100644
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -91,6 +91,7 @@ enum {
/* HOST_CTL bits */
HOST_RESET = (1 << 0), /* reset controller; self-clear */
HOST_IRQ_EN = (1 << 1), /* global IRQ enable */
+ HOST_MRSM = (1 << 2), /* MSI Revert to Single Message */
HOST_AHCI_EN = (1 << 31), /* AHCI enabled */
/* HOST_CAP bits */
--
Regards,
Alexander Gordeev
agordeev@redhat.com
next prev parent reply other threads:[~2013-09-04 14:15 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-02 8:59 [PATCH 0/4] " Alexander Gordeev
2013-09-02 8:59 ` [PATCH 1/4] PCI/MSI: Introduce " Alexander Gordeev
2013-09-03 14:19 ` Tejun Heo
2013-09-02 9:00 ` [PATCH 2/4] MSI/x86: Support " Alexander Gordeev
2013-09-03 13:32 ` Tejun Heo
2013-09-02 9:00 ` [PATCH 3/4] AHCI: Conserve interrupts with " Alexander Gordeev
2013-09-03 14:18 ` Tejun Heo
2013-09-03 16:19 ` Alexander Gordeev
2013-09-03 18:27 ` Tejun Heo
2013-09-04 7:22 ` Alexander Gordeev
2013-09-04 14:17 ` Alexander Gordeev [this message]
2013-09-04 14:55 ` Tejun Heo
2013-09-04 16:14 ` Alexander Gordeev
2013-09-04 18:06 ` Tejun Heo
2013-09-04 18:47 ` Alexander Gordeev
2013-09-04 18:51 ` Tejun Heo
2013-09-02 9:00 ` [PATCH 4/4] PCI/MSI: Get rid of pci_enable_msi_block_auto() interface Alexander Gordeev
2013-09-03 7:58 ` [PATCH v2 " Alexander Gordeev
2013-09-03 13:55 ` [PATCH 0/4] AHCI: Conserve interrupts with pci_enable_msi_block_part() interface Tejun Heo
2013-09-03 14:09 ` Tejun Heo
2013-09-04 12:32 ` Alexander Gordeev
2013-09-04 14:57 ` Tejun Heo
2013-09-03 14:57 ` Alexander Gordeev
2013-09-03 16:24 ` Tejun Heo
2013-09-04 8:06 ` Alexander Gordeev
2013-09-04 15:02 ` Tejun Heo
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