[PATCH V2] powerpc/85xx: workaround for chips with MSI hardware errata
Scott Wood
scottwood at freescale.com
Wed Mar 20 03:31:33 EST 2013
;On 03/19/2013 03:03:13 AM, Jia Hongtao-B38951 wrote:
>
>
> > -----Original Message-----
> > From: Kumar Gala [mailto:galak at kernel.crashing.org]
> > Sent: Friday, March 15, 2013 11:53 PM
> > To: Jia Hongtao-B38951
> > Cc: linuxppc-dev at lists.ozlabs.org; Wood Scott-B07421;
> > michael at ellerman.id.au; Li Yang-R58472
> > Subject: Re: [PATCH V2] powerpc/85xx: workaround for chips with MSI
> > hardware errata
> >
> >
> > On Mar 14, 2013, at 9:00 PM, Jia Hongtao-B38951 wrote:
> >
> > >
> > >
> > >> -----Original Message-----
> > >> From: Kumar Gala [mailto:galak at kernel.crashing.org]
> > >> Sent: Friday, March 15, 2013 4:05 AM
> > >> To: Jia Hongtao-B38951
> > >> Cc: linuxppc-dev at lists.ozlabs.org; Wood Scott-B07421;
> > >> michael at ellerman.id.au; Li Yang-R58472; Jia Hongtao-B38951
> > >> Subject: Re: [PATCH V2] powerpc/85xx: workaround for chips with
> MSI
> > >> hardware errata
> > >>
> > >>
> > >> On Mar 14, 2013, at 5:35 AM, Jia Hongtao wrote:
> > >>
> > >>> The MPIC version 2.0 has a MSI errata (errata PIC1 of mpc8544),
> It
> > >>> causes that neither MSI nor MSI-X can work fine. This is a
> > >>> workaround to allow MSI-X to function properly.
> > >>>
> > >>> Signed-off-by: Liu Shuo <soniccat.liu at gmail.com>
> > >>> Signed-off-by: Li Yang <leoli at freescale.com>
> > >>> Signed-off-by: Jia Hongtao <hongtao.jia at freescale.com>
> > >>> ---
> > >>> Changes for V2:
> > >>> - Address almost all the comments from Michael Ellerman for V1.
> > >>> Here is the link:
> > >>> http://patchwork.ozlabs.org/patch/226833/
> > >>>
> > >>> arch/powerpc/sysdev/fsl_msi.c | 65
> > >>> +++++++++++++++++++++++++++++++++++++++++--
> > >>> arch/powerpc/sysdev/fsl_msi.h | 2 ++
> > >>> 2 files changed, 64 insertions(+), 3 deletions(-)
> > >>>
> > >>> diff --git a/arch/powerpc/sysdev/fsl_msi.c
> > >>> b/arch/powerpc/sysdev/fsl_msi.c index 178c994..54cb83e 100644
> > >>> --- a/arch/powerpc/sysdev/fsl_msi.c
> > >>> +++ b/arch/powerpc/sysdev/fsl_msi.c
> > >>> @@ -98,8 +98,18 @@ static int fsl_msi_init_allocator(struct
> fsl_msi
> > >>> *msi_data)
> > >>>
> > >>> static int fsl_msi_check_device(struct pci_dev *pdev, int nvec,
> int
> > >>> type) {
> > >>> - if (type == PCI_CAP_ID_MSIX)
> > >>> - pr_debug("fslmsi: MSI-X untested, trying
> anyway.\n");
> > >>> + struct fsl_msi *msi;
> > >>> +
> > >>> + if (type == PCI_CAP_ID_MSI) {
> > >>> + /*
> > >>> + * MPIC version 2.0 has erratum PIC1. For now
> MSI
> > >>> + * could not work. So check to prevent MSI from
> > >>> + * being used on the board with this erratum.
> > >>> + */
> > >>> + list_for_each_entry(msi, &msi_head, list)
> > >>> + if (msi->feature & MSI_HW_ERRATA_ENDIAN)
> > >>> + return -EINVAL;
> > >>> + }
> > >>>
> > >>> return 0;
> > >>> }
> > >>> @@ -142,7 +152,17 @@ static void fsl_compose_msi_msg(struct
> pci_dev
> > >> *pdev, int hwirq,
> > >>> msg->address_lo = lower_32_bits(address);
> > >>> msg->address_hi = upper_32_bits(address);
> > >>>
> > >>> - msg->data = hwirq;
> > >>> + /*
> > >>> + * MPIC version 2.0 has erratum PIC1. It causes
> > >>> + * that neither MSI nor MSI-X can work fine.
> > >>> + * This is a workaround to allow MSI-X to function
> > >>> + * properly. It only works for MSI-X, we prevent
> > >>> + * MSI on buggy chips in fsl_msi_check_device().
> > >>> + */
> > >>> + if (msi_data->feature & MSI_HW_ERRATA_ENDIAN)
> > >>> + msg->data = __swab32(hwirq);
> > >>> + else
> > >>> + msg->data = hwirq;
> > >>>
> > >>> pr_debug("%s: allocated srs: %d, ibs: %d\n",
> > >>> __func__, hwirq / IRQS_PER_MSI_REG, hwirq %
> IRQS_PER_MSI_REG);
> > >> @@
> > >>> -361,6 +381,35 @@ static int fsl_msi_setup_hwirq(struct fsl_msi
> > >>> *msi,
> > >> struct platform_device *dev,
> > >>> return 0;
> > >>> }
> > >>>
> > >>> +/* MPIC version 2.0 has erratum PIC1 */ static int
> > >>> +mpic_has_errata(struct platform_device *dev) {
> > >>> + struct device_node *mpic_node;
> > >>> +
> > >>> + mpic_node = of_irq_find_parent(dev->dev.of_node);
> > >>> + if (mpic_node) {
> > >>> + u32 *reg_base, brr1 = 0;
> > >>> + /* Get the PIC reg base */
> > >>> + reg_base = of_iomap(mpic_node, 0);
> > >>> + of_node_put(mpic_node);
> > >>> + if (!reg_base) {
> > >>> + dev_err(&dev->dev, "ioremap problem
> failed.\n");
> > >>> + return -EIO;
> > >>> + }
> > >>> +
> > >>> + /* Get the mpic version from block revision
> register 1 */
> > >>> + brr1 = in_be32(reg_base + MPIC_FSL_BRR1);
> > >>> + iounmap(reg_base);
> > >>> + if ((brr1 & MPIC_FSL_BRR1_VER) == 0x0200)
> > >>> + return 1;
> > >>> + } else {
> > >>> + dev_err(&dev->dev, "MSI can't find his parent
> mpic node.\n");
> > >>> + return -ENODEV;
> > >>> + }
> > >>> +
> > >>> + return 0;
> > >>> +}
> > >>> +
> > >>> static const struct of_device_id fsl_of_msi_ids[]; static int
> > >>> fsl_of_msi_probe(struct platform_device *dev) { @@ -423,6
> +472,16 @@
> > >>> static int fsl_of_msi_probe(struct platform_device *dev)
> > >>>
> > >>> msi->feature = features->fsl_pic_ip;
> > >>>
> > >>> + if ((features->fsl_pic_ip & FSL_PIC_IP_MASK) ==
> FSL_PIC_IP_MPIC) {
> > >>> + rc = mpic_has_errata(dev);
> > >>> + if (rc > 0) {
> > >>> + msi->feature |= MSI_HW_ERRATA_ENDIAN;
> > >>> + } else if (rc < 0) {
> > >>> + err = rc;
> > >>> + goto error_out;
> > >>> + }
> > >>> + }
> > >>> +
> > >>> /*
> > >>> * Remember the phandle, so that we can match with any
> PCI nodes
> > >>> * that have an "fsl,msi" property.
> > >>> diff --git a/arch/powerpc/sysdev/fsl_msi.h
> > >>> b/arch/powerpc/sysdev/fsl_msi.h index 8225f86..7389e8e 100644
> > >>> --- a/arch/powerpc/sysdev/fsl_msi.h
> > >>> +++ b/arch/powerpc/sysdev/fsl_msi.h
> > >>> @@ -25,6 +25,8 @@
> > >>> #define FSL_PIC_IP_IPIC 0x00000002
> > >>> #define FSL_PIC_IP_VMPIC 0x00000003
> > >>>
> > >>> +#define MSI_HW_ERRATA_ENDIAN 0x00000010
> > >>> +
> > >>
> > >> Is there any reason to put this in fsl_msi.h rather than just in
> > >> fsl_msi.c itself?
> > >>
> > >> - k
> > >
> > > Actually no. This micro is only used by fsl_msi.c.
> > > Will move it to fsl_msi.c.
> > >
> > > Thanks.
> > > -Hongtao.
> >
> > Also, wondering if we can do the mpic version detection in mpic.c
> and not
> > here. I'm not sure what means we'd have to get back to the mpic
> struct
> > so we could possible use mpic->flags.
> >
>
> Use the MPIC version result in mpic.c was my plan.
> But as you point out there seems no obvious way to get the mpic
> struct.
> mpic struct is defined as an automatic variable in platform files.
> Also MSI driver is not so close to mpic driver under current
> architecture.
>
> If you get some elegant way to do this please feel free to tell me.
Declare a non-static function to retrieve the MPIC version.
-Scott
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