[PATCH V2] powerpc/85xx: workaround for chips with MSI hardware errata

[Jia Hongtao-B38951]

> -----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.

> 
> > struct fsl_msi {
> > 	struct irq_domain *irqhost;
> >
> > --
> > 1.8.0
> >
>