Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762707Ab3IDOPU (ORCPT ); Wed, 4 Sep 2013 10:15:20 -0400 Received: from mx1.redhat.com ([209.132.183.28]:15692 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754006Ab3IDOPR (ORCPT ); Wed, 4 Sep 2013 10:15:17 -0400 Date: Wed, 4 Sep 2013 16:17:11 +0200 From: Alexander Gordeev To: Tejun Heo Cc: linux-kernel@vger.kernel.org, x86@kernel.org, linux-pci@vger.kernel.org, linux-ide@vger.kernel.org, Ingo Molnar , Joerg Roedel , Jan Beulich , Bjorn Helgaas Subject: [PATCH v2 3/4] AHCI: Conserve interrupts with pci_enable_msi_block_part() interface Message-ID: <20130904141710.GD8726@dhcp-26-207.brq.redhat.com> References: <3bb1b4375655ecfde5017cc70973d078f2434d5d.1378111919.git.agordeev@redhat.com> <20130903141824.GD10522@htj.dyndns.org> <20130903161906.GC14221@dhcp-26-207.brq.redhat.com> <20130903182731.GA27092@mtj.dyndns.org> <20130904072256.GA8726@dhcp-26-207.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130904072256.GA8726@dhcp-26-207.brq.redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3119 Lines: 109 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 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/