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Message-ID: <20150517073331.GA30529@agordeev.usersys.redhat.com>
Date: Sun, 17 May 2015 08:33:32 +0100
From: Alexander Gordeev <agordeev@...hat.com>
To: Robert Richter <rric@...nel.org>
Cc: Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>, Tejun Heo <tj@...nel.org>,
Sunil Goutham <sgoutham@...ium.com>,
Jiang Liu <jiang.liu@...ux.intel.com>,
Robert Richter <rrichter@...ium.com>,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
linux-ide@...r.kernel.org
Subject: Re: [PATCH v2] AHCI: Add generic MSI-X interrupt support to SATA PCI
driver
On Mon, May 04, 2015 at 09:45:37AM +0200, Robert Richter wrote:
> From: Robert Richter <rrichter@...ium.com>
>
> This patch adds generic support for MSI-X interrupts to the SATA PCI
> driver. Only single interrupt support is implemented. Thus, per-port
> interrupts can not yet be enabled.
>
> The driver now checks the device for the existence of MSI-X and tries
> to enable the interrupt. Otherwise, if a device is not MSI-X capable,
> the initialization is skipped and MSI or intx interrupts are
> configured.
Hi Robert,
Sorry for jumping in late.
I have took a cursory look at your code and have a major concern.
You enable MSI-X for a single chip, but introduce a change to the
generic AHCI code.
In general MSI-X case, what makes you believe that IRQ vectors are
assigned continuously?
(Interface ahci_host_activate() kinda expects a contiguous vector
range, but MSI-X does not guarantee that at all).
Thanks!
> This patch also enables AHCI for Cavium Thunder SoCs that uses MSI-X.
>
> v2:
> * determine irq vector from pci_dev->msi_list
>
> Based on a patch from Sunil Goutham <sgoutham@...ium.com>.
>
> Signed-off-by: Robert Richter <rrichter@...ium.com>
> ---
> arch/arm64/Kconfig | 1 +
> drivers/ata/ahci.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++----
> 2 files changed, 75 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index b1f9a20a3677..2d95bbc0557e 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -157,6 +157,7 @@ config ARCH_THUNDER
> bool "Cavium Inc. Thunder SoC Family"
> help
> This enables support for Cavium's Thunder Family of SoCs.
> + select SATA_AHCI
>
> config ARCH_VEXPRESS
> bool "ARMv8 software model (Versatile Express)"
> diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
> index 49f1e6890587..36c88f6d8490 100644
> --- a/drivers/ata/ahci.c
> +++ b/drivers/ata/ahci.c
> @@ -42,6 +42,7 @@
> #include <linux/device.h>
> #include <linux/dmi.h>
> #include <linux/gfp.h>
> +#include <linux/msi.h>
> #include <scsi/scsi_host.h>
> #include <scsi/scsi_cmnd.h>
> #include <linux/libata.h>
> @@ -52,6 +53,7 @@
>
> enum {
> AHCI_PCI_BAR_STA2X11 = 0,
> + AHCI_PCI_BAR_CAVIUM = 0,
> AHCI_PCI_BAR_ENMOTUS = 2,
> AHCI_PCI_BAR_STANDARD = 5,
> };
> @@ -500,6 +502,9 @@ static const struct pci_device_id ahci_pci_tbl[] = {
> /* Enmotus */
> { PCI_DEVICE(0x1c44, 0x8000), board_ahci },
>
> + /* Cavium */
> + { PCI_DEVICE(0x177d, 0xa01c), .driver_data = board_ahci },
> +
> /* Generic, PCI class code for AHCI */
> { PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
> PCI_CLASS_STORAGE_SATA_AHCI, 0xffffff, board_ahci },
> @@ -1202,11 +1207,41 @@ static inline void ahci_gtf_filter_workaround(struct ata_host *host)
> {}
> #endif
>
> -static int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
> - struct ahci_host_priv *hpriv)
> +static int ahci_init_msix(struct pci_dev *pdev, unsigned int n_ports,
> + struct ahci_host_priv *hpriv)
> +{
> + int rc, nvec;
> + struct msix_entry entry = {};
> +
> + /* check if msix is supported */
> + nvec = pci_msix_vec_count(pdev);
> + if (nvec <= 0)
> + return 0;
> +
> + /* per-port msix interrupts are not supported */
> + if (n_ports > 1 && nvec >= n_ports)
> + return -ENOSYS;
> +
> + /* only enable the first entry (entry.entry = 0) */
> + rc = pci_enable_msix_exact(pdev, &entry, 1);
> + if (rc < 0)
> + return rc;
> +
> + return 1;
> +}
> +
> +static int __ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
> + struct ahci_host_priv *hpriv)
> {
> int rc, nvec;
>
> + nvec = ahci_init_msix(pdev, n_ports, hpriv);
> + if (nvec > 0)
> + return nvec;
> +
> + if (nvec && nvec != -ENOSYS)
> + dev_err(&pdev->dev, "failed to enable MSI-X: %d", nvec);
> +
> if (hpriv->flags & AHCI_HFLAG_NO_MSI)
> goto intx;
>
> @@ -1250,6 +1285,35 @@ static int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
> return 0;
> }
>
> +static struct msi_desc *msix_get_desc(struct pci_dev *dev, u16 entry)
> +{
> + struct msi_desc *desc;
> +
> + list_for_each_entry(desc, &dev->msi_list, list) {
> + if (desc->msi_attrib.entry_nr == entry)
> + return desc;
> + }
> +
> + return NULL;
> +}
> +
> +static int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
> + struct ahci_host_priv *hpriv)
> +{
> + struct msi_desc *desc;
> +
> + __ahci_init_interrupts(pdev, n_ports, hpriv);
> +
> + if (!pdev->msix_enabled)
> + return pdev->irq;
> +
> + desc = msix_get_desc(pdev, 0); /* first entry */
> + if (!desc)
> + return -ENODEV;
> +
> + return desc->irq;
> +}
> +
> static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
> {
> unsigned int board_id = ent->driver_data;
> @@ -1260,6 +1324,7 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
> struct ata_host *host;
> int n_ports, i, rc;
> int ahci_pci_bar = AHCI_PCI_BAR_STANDARD;
> + int irq;
>
> VPRINTK("ENTER\n");
>
> @@ -1285,11 +1350,13 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
> dev_info(&pdev->dev,
> "PDC42819 can only drive SATA devices with this driver\n");
>
> - /* Both Connext and Enmotus devices use non-standard BARs */
> + /* Some devices use non-standard BARs */
> if (pdev->vendor == PCI_VENDOR_ID_STMICRO && pdev->device == 0xCC06)
> ahci_pci_bar = AHCI_PCI_BAR_STA2X11;
> else if (pdev->vendor == 0x1c44 && pdev->device == 0x8000)
> ahci_pci_bar = AHCI_PCI_BAR_ENMOTUS;
> + else if (pdev->vendor == 0x177d && pdev->device == 0xa01c)
> + ahci_pci_bar = AHCI_PCI_BAR_CAVIUM;
>
> /*
> * The JMicron chip 361/363 contains one SATA controller and one
> @@ -1411,7 +1478,9 @@ 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));
>
> - ahci_init_interrupts(pdev, n_ports, hpriv);
> + irq = ahci_init_interrupts(pdev, n_ports, hpriv);
> + if (irq < 0)
> + return irq;
>
> host = ata_host_alloc_pinfo(&pdev->dev, ppi, n_ports);
> if (!host)
> @@ -1463,7 +1532,7 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
>
> pci_set_master(pdev);
>
> - return ahci_host_activate(host, pdev->irq, &ahci_sht);
> + return ahci_host_activate(host, irq, &ahci_sht);
> }
>
> module_pci_driver(ahci_pci_driver);
> --
> 2.1.1
>
> --
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--
Regards,
Alexander Gordeev
agordeev@...hat.com
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