On Thu, 6 Jun 2013 18:41:24 +0200, Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx> wrote:
> This commit introduces the support for the MSI interrupts in the
> armada-370-xp interrupt controller driver. It registers an MSI chip to
> the MSI chip registry, which will be used by the Marvell PCIe host
> controller driver.
>
> The MSI interrupts use the 16 high doorbells, and are therefore
> notified using IRQ1 of the main interrupt controller.
>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/irqchip/irq-armada-370-xp.c | 166 +++++++++++++++++++++++++++++++++++-
> 1 file changed, 165 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/irqchip/irq-armada-370-xp.c b/drivers/irqchip/irq-armada-370-xp.c
> index 26adc74..c7c904d 100644
> --- a/drivers/irqchip/irq-armada-370-xp.c
> +++ b/drivers/irqchip/irq-armada-370-xp.c
> @@ -22,6 +22,8 @@
> #include <linux/of_address.h>
> #include <linux/of_irq.h>
> #include <linux/irqdomain.h>
> +#include <linux/slab.h>
> +#include <linux/msi.h>
> #include <asm/mach/arch.h>
> #include <asm/exception.h>
> #include <asm/smp_plat.h>
> @@ -51,12 +53,22 @@
> #define IPI_DOORBELL_START (0)
> #define IPI_DOORBELL_END (8)
> #define IPI_DOORBELL_MASK 0xFF
> +#define PCI_MSI_DOORBELL_START (16)
> +#define PCI_MSI_DOORBELL_NR (16)
> +#define PCI_MSI_DOORBELL_END (32)
> +#define PCI_MSI_DOORBELL_MASK 0xFFFF0000
>
> static DEFINE_RAW_SPINLOCK(irq_controller_lock);
>
> static void __iomem *per_cpu_int_base;
> static void __iomem *main_int_base;
> static struct irq_domain *armada_370_xp_mpic_domain;
> +#ifdef CONFIG_PCI_MSI
> +static struct irq_domain *armada_370_xp_msi_domain;
> +static DECLARE_BITMAP(msi_used, PCI_MSI_DOORBELL_NR);
> +static DEFINE_MUTEX(msi_used_lock);
> +static phys_addr_t msi_doorbell_addr;
> +#endif
>
> /*
> * In SMP mode:
> @@ -87,6 +99,126 @@ static void armada_370_xp_irq_unmask(struct irq_data *d)
> ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
> }
>
> +#ifdef CONFIG_PCI_MSI
> +static int armada_370_xp_alloc_msi(void)
> +{
> + int hwirq;
> +
> + mutex_lock(&msi_used_lock);
> + hwirq = find_first_zero_bit(&msi_used, PCI_MSI_DOORBELL_NR);
> + if (hwirq >= PCI_MSI_DOORBELL_NR)
> + hwirq = -ENOSPC;
> + else
> + set_bit(hwirq, msi_used);
> + mutex_unlock(&msi_used_lock);
> +
> + return hwirq;
> +}
> +
> +static void armada_370_xp_free_msi(int hwirq)
> +{
> + mutex_lock(&msi_used_lock);
> + if (!test_bit(hwirq, msi_used))
> + pr_err("trying to free unused MSI#%d\n", hwirq);
> + else
> + clear_bit(hwirq, msi_used);
> + mutex_unlock(&msi_used_lock);
> +}
> +
> +static int armada_370_xp_setup_msi_irq(struct msi_chip *chip,
> + struct pci_dev *pdev,
> + struct msi_desc *desc)
> +{
> + struct msi_msg msg;
> + int hwirq, irq;
> +
> + hwirq = armada_370_xp_alloc_msi();
> + if (hwirq < 0)
> + return hwirq;
> +
> + irq = irq_create_mapping(armada_370_xp_msi_domain, hwirq);
> + if (!irq) {
> + armada_370_xp_free_msi(hwirq);
> + return -EINVAL;
> + }
This looks like something that the irq_domain should handle for you.
It would be good to have a variant of irq_create_mapping() that keeps
track of available hwirqs, allocates a free one, and maps it all with
one function call. I can see that being useful by other MSI interrupt
controllers and would eliminate needing to open-code it above.
take a look at the irqdomain/test branch on git://git.secretlab.ca/git/linux
I'm hoping to push that series into v3.11 and it simplifies the
irq_domain code quite a bit. It would be easy to build an
irq_create_mapping() variant on top of that. Take a look at
irq_create_direct_mapping() for inspiration (although that function does
it the other way around. It allocates a virq and uses that number for
the hwirq number)
> +static int armada_370_xp_msi_init(struct device_node *node)
> +{
> + struct msi_chip *msi_chip;
> + u32 reg;
> +
> + msi_chip = kzalloc(sizeof(*msi_chip), GFP_KERNEL);
devm_kzalloc() so it gets freed on failure or unbind; although for this
device you may not care.
> + if (!msi_chip)
> + return -ENOMEM;
> +
> + armada_370_xp_msi_domain =
> + irq_domain_add_linear(NULL, PCI_MSI_DOORBELL_NR,
> + &armada_370_xp_msi_irq_ops, NULL);
> + if (!armada_370_xp_msi_domain) {
> + kfree(msi_chip);
> + return -ENOMEM;
> + }
> +
> + msi_chip->of_node = node;
> + msi_chip->setup_irq = armada_370_xp_setup_msi_irq;
> + msi_chip->teardown_irq = armada_370_xp_teardown_msi_irq;
> +
> + msi_chip_add(msi_chip);
> +
> + reg = readl(per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_MSK_OFFS)
> + | PCI_MSI_DOORBELL_MASK;
> +
> + writel(reg, per_cpu_int_base +
> + ARMADA_370_XP_IN_DRBEL_MSK_OFFS);
> +
> + /* Unmask IPI interrupt */
> + writel(1, per_cpu_int_base + ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
> +
> + return 0;
> +}
> +#else
> +static inline int armada_370_xp_msi_init(struct device_node *node) { return 0; }
> +#endif
> +
> #ifdef CONFIG_SMP
> static int armada_xp_set_affinity(struct irq_data *d,
> const struct cpumask *mask_val, bool force)
> @@ -214,12 +346,39 @@ armada_370_xp_handle_irq(struct pt_regs *regs)
> if (irqnr > 1022)
> break;
>
> - if (irqnr > 0) {
> + if (irqnr > 1) {
> irqnr = irq_find_mapping(armada_370_xp_mpic_domain,
> irqnr);
> handle_IRQ(irqnr, regs);
> continue;
> }
> +
> +#ifdef CONFIG_PCI_MSI
> + /* MSI handling */
> + if (irqnr == 1) {
> + u32 msimask, msinr;
> +
> + msimask = readl_relaxed(per_cpu_int_base +
> + ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS)
> + & PCI_MSI_DOORBELL_MASK;
> +
> + writel(~PCI_MSI_DOORBELL_MASK, per_cpu_int_base +
> + ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS);
> +
> + for (msinr = PCI_MSI_DOORBELL_START;
> + msinr < PCI_MSI_DOORBELL_END; msinr++) {
> + int irq;
> +
> + if (!(msimask & BIT(msinr)))
> + continue;
> +
> + irq = irq_find_mapping(armada_370_xp_msi_domain,
> + msinr - 16);
> + handle_IRQ(irq, regs);
> + }
> + }
> +#endif
> +
> #ifdef CONFIG_SMP
> /* IPI Handling */
> if (irqnr == 0) {
> @@ -269,6 +428,9 @@ static int __init armada_370_xp_mpic_of_init(struct device_node *node,
> resource_size(&per_cpu_int_res));
> BUG_ON(!per_cpu_int_base);
>
> + msi_doorbell_addr = main_int_res.start +
> + ARMADA_370_XP_SW_TRIG_INT_OFFS;
> +
> control = readl(main_int_base + ARMADA_370_XP_INT_CONTROL);
>
> armada_370_xp_mpic_domain =
> @@ -292,6 +454,8 @@ static int __init armada_370_xp_mpic_of_init(struct device_node *node,
>
> #endif
>
> + armada_370_xp_msi_init(node);
> +
> set_handle_irq(armada_370_xp_handle_irq);
>
> return 0;
> --
> 1.8.1.2
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
--
Grant Likely, B.Sc, P.Eng.
Secret Lab Technologies, Ltd.
--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
