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Message-Id: <1215811018-15270-5-git-send-email-matthew@wil.cx>
Date: Fri, 11 Jul 2008 17:16:57 -0400
From: Matthew Wilcox <matthew@....cx>
To: linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: grundler@...isc-linux.org, mingo@...e.hu, tglx@...utronix.de,
jgarzik@...ox.com, linux-ide@...r.kernel.org,
suresh.b.siddha@...el.com, benh@...nel.crashing.org,
jbarnes@...tuousgeek.org, rdunlap@...otime.net,
mtk.manpages@...il.com, ebiederm@...ssion.com,
Matthew Wilcox <matthew@....cx>,
Matthew Wilcox <willy@...ux.intel.com>
Subject: [PATCH 5/6] AHCI: Request multiple MSIs
AHCI controllers can support up to 16 interrupts, one per port. This
saves us a readl() in the interrupt path to determine which port has
generated the interrupt.
Signed-off-by: Matthew Wilcox <willy@...ux.intel.com>
---
drivers/ata/ahci.c | 104 +++++++++++++++++++++++++++++++++++++++++++++++++--
1 files changed, 99 insertions(+), 5 deletions(-)
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 5e6468a..a3f6331 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -102,6 +102,7 @@ enum {
/* HOST_CTL bits */
HOST_RESET = (1 << 0), /* reset controller; self-clear */
HOST_IRQ_EN = (1 << 1), /* global IRQ enable */
+ HOST_MSI_RSM = (1 << 2), /* Revert to Single Message */
HOST_AHCI_EN = (1 << 31), /* AHCI enabled */
/* HOST_CAP bits */
@@ -1771,6 +1772,19 @@ static void ahci_port_intr(struct ata_port *ap)
}
}
+static irqreturn_t ahci_msi_interrupt(int irq, void *dev_instance)
+{
+ struct ata_host *host = dev_instance;
+ int port = get_irq_subchannel(irq);
+ struct ata_port *ap = host->ports[port];
+
+ spin_lock(&ap->host->lock);
+ ahci_port_intr(ap);
+ spin_unlock(&ap->host->lock);
+
+ return IRQ_HANDLED;
+}
+
static irqreturn_t ahci_interrupt(int irq, void *dev_instance)
{
struct ata_host *host = dev_instance;
@@ -2220,6 +2234,80 @@ static void ahci_p5wdh_workaround(struct ata_host *host)
}
}
+static int ahci_request_irq(struct pci_dev *pdev, struct ata_host *host,
+ int n_irqs)
+{
+ int rc;
+
+ if (n_irqs) {
+ rc = pci_enable_msi_block(pdev, n_irqs);
+ if (rc)
+ return rc;
+ }
+
+ if (n_irqs > 1) {
+ void __iomem *mmio = host->iomap[AHCI_PCI_BAR];
+ u32 host_ctl = readl(mmio + HOST_CTL);
+ if (host_ctl & HOST_MSI_RSM)
+ goto try_different;
+ rc = devm_request_irq(host->dev, pdev->irq, ahci_msi_interrupt,
+ IRQF_DISABLED,
+ dev_driver_string(host->dev), host);
+ } else {
+ rc = devm_request_irq(host->dev, pdev->irq, ahci_interrupt,
+ IRQF_SHARED,
+ dev_driver_string(host->dev), host);
+ }
+
+ if (!rc)
+ return 0;
+
+ try_different:
+ pci_disable_msi(pdev);
+ pci_intx(pdev, 1);
+ return (n_irqs == 1) ? rc : 1;
+}
+
+/*
+ * We only need one interrupt per port (plus one for CCC which isn't
+ * supported yet), but some AHCI controllers refuse to use multiple MSIs
+ * unless they get the maximum number of interrupts. We don't support the
+ * mode where fewer interrupts are assigned than we have ports.
+ */
+static int ahci_setup_irqs(struct pci_dev *pdev, struct ata_host *host)
+{
+ struct ahci_host_priv *hpriv = host->private_data;
+ int n_irqs, pos, rc;
+ u16 control;
+
+ if (hpriv->flags & AHCI_HFLAG_NO_MSI)
+ goto no_msi;
+
+ rc = ahci_request_irq(pdev, host, host->n_ports);
+ if (rc == 0)
+ return 0;
+ if (rc < 0)
+ goto no_msi;
+
+ /* Find out how many it might want */
+ pos = pci_find_capability(pdev, PCI_CAP_ID_MSI);
+ pci_read_config_word(pdev, pos + PCI_MSI_FLAGS, &control);
+ n_irqs = 1 << ((control & PCI_MSI_FLAGS_QMASK) >> 1);
+
+ rc = ahci_request_irq(pdev, host, n_irqs);
+ if (rc == 0)
+ return 0;
+ if (rc < 0)
+ goto no_msi;
+
+ rc = ahci_request_irq(pdev, host, 1);
+ if (rc == 0)
+ return 0;
+
+ no_msi:
+ return ahci_request_irq(pdev, host, 0);
+}
+
static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
{
static int printed_version;
@@ -2278,9 +2366,6 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
(pdev->revision == 0xa1 || pdev->revision == 0xa2))
hpriv->flags |= AHCI_HFLAG_NO_MSI;
- if ((hpriv->flags & AHCI_HFLAG_NO_MSI) || pci_enable_msi(pdev))
- pci_intx(pdev, 1);
-
/* save initial config */
ahci_save_initial_config(pdev, hpriv);
@@ -2335,8 +2420,17 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
ahci_print_info(host);
pci_set_master(pdev);
- return ata_host_activate(host, pdev->irq, ahci_interrupt, IRQF_SHARED,
- &ahci_sht);
+
+ rc = ata_host_start(host);
+ if (rc)
+ return rc;
+
+ rc = ahci_setup_irqs(pdev, host);
+ if (rc)
+ return rc;
+
+ rc = ata_host_register(host, &ahci_sht);
+ return rc;
}
static int __init ahci_init(void)
--
1.5.5.4
--
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