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Message-ID: <20141105230952.GH6168@google.com>
Date: Wed, 5 Nov 2014 16:09:52 -0700
From: Bjorn Helgaas <bhelgaas@...gle.com>
To: Jiang Liu <jiang.liu@...ux.intel.com>
Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
Randy Dunlap <rdunlap@...radead.org>,
Yinghai Lu <yinghai@...nel.org>,
Borislav Petkov <bp@...en8.de>,
Grant Likely <grant.likely@...aro.org>,
Marc Zyngier <marc.zyngier@....com>,
Yingjoe Chen <yingjoe.chen@...iatek.com>,
Matthias Brugger <matthias.bgg@...il.com>,
Yijing Wang <wangyijing@...wei.com>,
Alexander Gordeev <agordeev@...hat.com>,
Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Tony Luck <tony.luck@...el.com>,
Joerg Roedel <joro@...tes.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
x86@...nel.org, linux-kernel@...r.kernel.org,
linux-pci@...r.kernel.org, linux-acpi@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org
Subject: Re: [Patch Part2 v4 21/31] PCI/MSI: enhance PCI MSI core to support
hierarchy irqdomain
On Tue, Nov 04, 2014 at 08:01:55PM +0800, Jiang Liu wrote:
In your topic:
PCI/MSI: enhance PCI MSI core to support hierarchy irqdomain
There's no need to repeat "PCI MSI". Please run "git log --oneline
drivers/pci/msi.c" and make your similar (capitalize the first word).
> Enhance PCI MSI core to support hierarchy irqdomain, so the common
> code could be shared among architectures.
>
> Signed-off-by: Jiang Liu <jiang.liu@...ux.intel.com>
> ---
> drivers/pci/Kconfig | 4 ++
> drivers/pci/msi.c | 126 +++++++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/msi.h | 11 +++++
> 3 files changed, 141 insertions(+)
>
> diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
> index b9db0f2ce11f..022e89745f86 100644
> --- a/drivers/pci/Kconfig
> +++ b/drivers/pci/Kconfig
> @@ -16,6 +16,10 @@ config PCI_MSI
>
> If you don't know what to do here, say Y.
>
> +config PCI_MSI_IRQ_DOMAIN
> + bool
> + depends on PCI_MSI && IRQ_DOMAIN_HIERARCHY
> +
> config PCI_DEBUG
> bool "PCI Debugging"
> depends on PCI && DEBUG_KERNEL
> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index da181c59394b..7423ee16972f 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -19,6 +19,7 @@
> #include <linux/errno.h>
> #include <linux/io.h>
> #include <linux/slab.h>
> +#include <linux/irqdomain.h>
>
> #include "pci.h"
>
> @@ -1098,3 +1099,128 @@ int pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries,
> return nvec;
> }
> EXPORT_SYMBOL(pci_enable_msix_range);
> +
> +#ifdef CONFIG_PCI_MSI_IRQ_DOMAIN
Space, not tab.
> +static inline irq_hw_number_t
> +msi_get_hwirq(struct pci_dev *pdev, struct msi_desc *msidesc)
The convention in this file is "struct pci_dev *dev". And "struct msi_desc
*desc" (or maybe "*entry"). Try to converge things, not diverge them.
> +{
> + return (irq_hw_number_t)msidesc->msi_attrib.entry_nr |
> + PCI_DEVID(pdev->bus->number, pdev->devfn) << 11 |
> + (pci_domain_nr(pdev->bus) & 0xFFFFFFFF) << 27;
Where does this bit layout come from? Is this defined in the spec
somewhere? A reference would help.
> +}
> +
> +static int msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
> + unsigned int nr_irqs, void *arg)
> +{
> + int i, ret;
> + irq_hw_number_t hwirq = arch_msi_irq_domain_get_hwirq(arg);
> +
> + if (irq_find_mapping(domain, hwirq) > 0)
> + return -EEXIST;
> +
> + ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, arg);
> + if (ret >= 0)
if (ret < 0)
return ret;
and un-indent the mainline code below. Then it's obvious that this is the
normal case, not the error case.
> + for (i = 0; i < nr_irqs; i++) {
> + irq_domain_set_hwirq_and_chip(domain, virq + i,
> + hwirq + i, &msi_chip, (void *)(long)i);
> + __irq_set_handler(virq + i, handle_edge_irq, 0, "edge");
> + }
> +
> + return ret;
> +}
> +
> +static void msi_domain_free(struct irq_domain *domain, unsigned int virq,
> + unsigned int nr_irqs)
> +{
> + int i;
> +
> + for (i = 0; i < nr_irqs; i++) {
> + struct msi_desc *msidesc = irq_get_msi_desc(virq);
> +
> + if (msidesc)
> + msidesc->irq = 0;
> + }
> + irq_domain_free_irqs_top(domain, virq, nr_irqs);
> +}
> +
> +static int msi_domain_activate(struct irq_domain *domain,
> + struct irq_data *irq_data)
> +{
> + int ret = 0;
> + struct msi_msg msg;
> +
> + /*
> + * irq_data->chip_data is MSI/MSIx offset.
"MSI-X", as you wrote on the next line.
> + * MSI-X message is written per-IRQ, the offset is always 0.
> + * MSI message denotes a contiguous group of IRQs, written for 0th IRQ.
> + */
> + if (!irq_data->chip_data) {
if (irq_data->chip_data)
return 0;
and un-indent the mainline code below, and drop the "ret = 0" init above.
> + ret = irq_chip_compose_msi_msg(irq_data, &msg);
> + if (ret == 0)
if (ret)
return ret;
> + write_msi_msg(irq_data->irq, &msg);
> + }
> +
> + return ret;
return 0;
> +}
> +
> +static int msi_domain_deactivate(struct irq_domain *domain,
> + struct irq_data *irq_data)
> +{
> + struct msi_msg msg;
> +
> + if (irq_data->chip_data) {
> + memset(&msg, 0, sizeof(msg));
> + write_msi_msg(irq_data->irq, &msg);
> + }
> +
> + return 0;
> +}
> +
> +static struct irq_domain_ops msi_domain_ops = {
> + .alloc = msi_domain_alloc,
> + .free = msi_domain_free,
> + .activate = msi_domain_activate,
> + .deactivate = msi_domain_deactivate,
> +};
> +
> +struct irq_domain *msi_create_irq_domain(struct irq_domain *parent)
> +{
> + struct irq_domain *domain;
> +
> + domain = irq_domain_add_tree(NULL, &msi_domain_ops, NULL);
> + if (domain)
if (!domain)
return NULL;
and un-indent this:
> + domain->parent = parent;
> +
> + return domain;
> +}
> +
> +int msi_irq_domain_alloc_irqs(struct irq_domain *domain, int type,
> + struct pci_dev *dev, void *arg)
> +{
> + int i, virq;
> + struct msi_desc *msidesc;
> + int node = dev_to_node(&dev->dev);
> +
> + list_for_each_entry(msidesc, &dev->msi_list, list) {
> + arch_msi_irq_domain_set_hwirq(arg, msi_get_hwirq(dev, msidesc));
> + virq = irq_domain_alloc_irqs(domain, msidesc->nvec_used,
> + node, arg);
> + if (virq < 0) {
> + /* Special handling for pci_enable_msi_range(). */
> + return (type == PCI_CAP_ID_MSI &&
> + msidesc->nvec_used > 1) ? 1 : -ENOSPC;
I think "if" would be easier to read than this ternary expression.
> + }
> + for (i = 0; i < msidesc->nvec_used; i++)
> + irq_set_msi_desc_off(virq + i, i, msidesc);
> + }
> +
> + list_for_each_entry(msidesc, &dev->msi_list, list)
> + if (msidesc->nvec_used == 1)
> + dev_dbg(&dev->dev, "irq %d for MSI/MSI-X\n", virq);
> + else
> + dev_dbg(&dev->dev, "irq [%d-%d] for MSI/MSI-X\n",
> + virq, virq + msidesc->nvec_used - 1);
> +
> + return 0;
> +}
> +#endif /* CONFIG_PCI_MSI_IRQ_DOMAIN */
> diff --git a/include/linux/msi.h b/include/linux/msi.h
> index 44f4746d033b..05dcd425f82b 100644
> --- a/include/linux/msi.h
> +++ b/include/linux/msi.h
> @@ -75,4 +75,15 @@ struct msi_chip {
> void (*teardown_irq)(struct msi_chip *chip, unsigned int irq);
> };
>
> +#ifdef CONFIG_PCI_MSI_IRQ_DOMAIN
Use a space here, not a tab.
> +extern struct irq_chip msi_chip;
I don't think "msi_chip" is a good name. "Chip" only hints that it's a
semiconductor integrated circuit; it doesn't say anything about what it
does. I've suggested "msi_controller" elsewhere.
Why does this need to be exported? And why should there be only one in a
system?
> +extern struct irq_domain *msi_create_irq_domain(struct irq_domain *parent);
> +extern int msi_irq_domain_alloc_irqs(struct irq_domain *domain, int type,
> + struct pci_dev *dev, void *arg);
> +
> +extern irq_hw_number_t arch_msi_irq_domain_get_hwirq(void *arg);
> +extern void arch_msi_irq_domain_set_hwirq(void *arg, irq_hw_number_t hwirq);
Look at the rest of the file and notice that the existing code does not use
"extern" on function declarations.
> +#endif /* CONFIG_PCI_MSI_IRQ_DOMAIN */
Use a space here (not a tab), like the #endif just below.
> #endif /* LINUX_MSI_H */
> --
> 1.7.10.4
>
--
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