[PATCH 2/2 v3] irqchip/Layerscape: Add SCFG MSI controller support
Minghuan Lian
minghuan.lian at nxp.com
Wed Feb 24 19:21:05 PST 2016
Hi Marc,
I am sorry for the delayed response due to the Chinese Spring Festival holiday.
Thank you very much for the review.
Please see my comments inline.
Thanks,
Minghuan
> -----Original Message-----
> From: Marc Zyngier [mailto:marc.zyngier at arm.com]
> Sent: Thursday, February 18, 2016 1:30 AM
> To: Minghuan Lian <minghuan.lian at nxp.com>;
> linux-arm-kernel at lists.infradead.org
> Cc: Thomas Gleixner <tglx at linutronix.de>; Jason Cooper
> <jason at lakedaemon.net>; Roy Zang <roy.zang at nxp.com>; Mingkai Hu
> <mingkai.hu at nxp.com>; Stuart Yoder <stuart.yoder at nxp.com>; Yang-Leo Li
> <leoyang.li at nxp.com>; linux-kernel at vger.kernel.org
> Subject: Re: [PATCH 2/2 v3] irqchip/Layerscape: Add SCFG MSI controller
> support
>
> Minguan,
>
> Please CC LKML for any irqchip related patch - see the MAINTAINER file.
>
> On 02/02/16 09:00, Minghuan Lian wrote:
> > Some kind of NXP Layerscape SoC provides a MSI implementation which
> > uses two SCFG registers MSIIR and MSIR to support 32 MSI interrupts
> > for each PCIe controller.
> > The patch is to support it.
> >
> > Signed-off-by: Minghuan Lian <Minghuan.Lian at nxp.com>
> > ---
> >
> > Change log
> > v3:
> > 1. call of_node_to_fwnode()
> > v2:
> > 1. rename ls1-msi to ls-scfg-msi
> > 2. remove reg-names MSIIR MSIR
> > 3. remove calling set_irq_flags()
> >
> > drivers/irqchip/Kconfig | 5 +
> > drivers/irqchip/Makefile | 1 +
> > drivers/irqchip/irq-ls-scfg-msi.c | 244
> > ++++++++++++++++++++++++++++++++++++++
> > 3 files changed, 250 insertions(+)
> > create mode 100644 drivers/irqchip/irq-ls-scfg-msi.c
> >
> > diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig index
> > fb50911..0f2a3c3 100644
> > --- a/drivers/irqchip/Kconfig
> > +++ b/drivers/irqchip/Kconfig
> > @@ -218,3 +218,8 @@ config IRQ_MXS
> > def_bool y if MACH_ASM9260 || ARCH_MXS
> > select IRQ_DOMAIN
> > select STMP_DEVICE
> > +
> > +config LS_SCFG_MSI
> > + def_bool y if SOC_LS1021A || ARCH_LAYERSCAPE
> > + depends on PCI && PCI_MSI
> > + select PCI_MSI_IRQ_DOMAIN
> > diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile index
> > 18caacb..37e12de 100644
> > --- a/drivers/irqchip/Makefile
> > +++ b/drivers/irqchip/Makefile
> > @@ -59,3 +59,4 @@ obj-$(CONFIG_ARCH_SA1100) += irq-sa11x0.o
> > obj-$(CONFIG_INGENIC_IRQ) += irq-ingenic.o
> > obj-$(CONFIG_IMX_GPCV2) += irq-imx-gpcv2.o
> > obj-$(CONFIG_PIC32_EVIC) += irq-pic32-evic.o
> > +obj-$(CONFIG_LS_SCFG_MSI) += irq-ls-scfg-msi.o
> > diff --git a/drivers/irqchip/irq-ls-scfg-msi.c
> > b/drivers/irqchip/irq-ls-scfg-msi.c
> > new file mode 100644
> > index 0000000..f57a72c
> > --- /dev/null
> > +++ b/drivers/irqchip/irq-ls-scfg-msi.c
> > @@ -0,0 +1,244 @@
> > +/*
> > + * NXP SCFG MSI(-X) support
> > + *
> > + * Copyright (C) 2016 NXP Semiconductor.
> > + *
> > + * Author: Minghuan Lian <Minghuan.Lian at nxp.com>
> > + *
> > + * This program is free software; you can redistribute it and/or
> > +modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + */
> > +
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/msi.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/irq.h>
> > +#include <linux/irqchip/chained_irq.h> #include <linux/irqdomain.h>
> > +#include <linux/of_pci.h> #include <linux/of_platform.h> #include
> > +<linux/spinlock.h>
> > +
> > +#define MSI_MAX_IRQS 32
> > +#define MSI_IBS_SHIFT 3
> > +#define MSIR 4
> > +
> > +struct ls_scfg_msi {
> > + spinlock_t lock;
> > + struct platform_device *pdev;
> > + struct irq_domain *parent;
> > + struct irq_domain *msi_domain;
> > + void __iomem *regs;
> > + phys_addr_t msiir_addr;
> > + u32 nr_irqs;
> > + int irq;
> > + DECLARE_BITMAP(used, MSI_MAX_IRQS);
> > +};
> > +
> > +static struct irq_chip ls_scfg_msi_irq_chip = {
> > + .name = "MSI",
> > + .irq_enable = pci_msi_unmask_irq,
> > + .irq_disable = pci_msi_mask_irq,
> > + .irq_mask = pci_msi_mask_irq,
> > + .irq_unmask = pci_msi_unmask_irq,
> > +};
>
> You don't need all of this. mask/unmask are enough.
[Lian Minghuan-B31939] ok. I will fix it.
>
> > +
> > +static struct msi_domain_info ls_scfg_msi_domain_info = {
> > + .flags = (MSI_FLAG_USE_DEF_DOM_OPS |
> > + MSI_FLAG_USE_DEF_CHIP_OPS |
> > + MSI_FLAG_PCI_MSIX),
> > + .chip = &ls_scfg_msi_irq_chip,
> > +};
> > +
> > +static void ls_scfg_msi_compose_msg(struct irq_data *data, struct
> > +msi_msg *msg) {
> > + struct ls_scfg_msi *msi_data = irq_data_get_irq_chip_data(data);
> > +
> > + msg->address_hi = upper_32_bits(msi_data->msiir_addr);
> > + msg->address_lo = lower_32_bits(msi_data->msiir_addr);
> > + msg->data = data->hwirq << MSI_IBS_SHIFT; }
> > +
> > +static int ls_scfg_msi_set_affinity(struct irq_data *irq_data,
> > + const struct cpumask *mask, bool force) {
> > + return -EINVAL;
> > +}
> > +
> > +static struct irq_chip ls_scfg_msi_parent_chip = {
> > + .name = "LS SCFG MSI",
>
> Worth making this shorter. "SCFG" should be enough.
>
[Lian Minghuan-B31939] ok. I will rename it to "scfg"
> > + .irq_compose_msi_msg = ls_scfg_msi_compose_msg,
> > + .irq_set_affinity = ls_scfg_msi_set_affinity,
> > +};
> > +
> > +static int ls_scfg_msi_domain_irq_alloc(struct irq_domain *domain,
> > + unsigned int virq,
> > + unsigned int nr_irqs,
> > + void *args)
> > +{
> > + struct ls_scfg_msi *msi_data = domain->host_data;
> > + int pos, err = 0;
> > +
> > + WARN_ON(nr_irqs != 1);
> > +
> > + spin_lock(&msi_data->lock);
> > + pos = find_first_zero_bit(msi_data->used, msi_data->nr_irqs);
> > + if (pos < msi_data->nr_irqs)
> > + __set_bit(pos, msi_data->used);
> > + else
> > + err = -ENOSPC;
> > + spin_unlock(&msi_data->lock);
> > +
> > + if (err)
> > + return err;
> > +
> > + irq_domain_set_info(domain, virq, pos,
> > + &ls_scfg_msi_parent_chip, msi_data,
> > + handle_simple_irq, NULL, NULL);
> > +
> > + return 0;
> > +}
> > +
> > +static void ls_scfg_msi_domain_irq_free(struct irq_domain *domain,
> > + unsigned int virq, unsigned int nr_irqs) {
> > + struct irq_data *d = irq_domain_get_irq_data(domain, virq);
> > + struct ls_scfg_msi *msi_data = irq_data_get_irq_chip_data(d);
> > + int pos;
> > +
> > + pos = d->hwirq;
> > + if (pos < 0 || pos >= msi_data->nr_irqs) {
> > + pr_err("failed to teardown msi. Invalid hwirq %d\n", pos);
> > + return;
> > + }
> > +
> > + spin_lock(&msi_data->lock);
> > + __clear_bit(pos, msi_data->used);
> > + spin_unlock(&msi_data->lock);
> > +}
> > +
> > +static const struct irq_domain_ops ls_scfg_msi_domain_ops = {
> > + .alloc = ls_scfg_msi_domain_irq_alloc,
> > + .free = ls_scfg_msi_domain_irq_free,
> > +};
> > +
> > +static void ls_scfg_msi_irq_handler(struct irq_desc *desc) {
> > + struct ls_scfg_msi *msi_data = irq_desc_get_handler_data(desc);
> > + unsigned long val;
> > + int pos, virq;
> > +
> > + chained_irq_enter(irq_desc_get_chip(desc), desc);
> > +
> > + val = ioread32be(msi_data->regs + MSIR);
>
> Is the device guaranteed to always be BE?
[Lian Minghuan-B31939] Yes, this register on all kinds of current Layerscape SoC is big-endian format.
>
> > + for_each_set_bit(pos, &val, msi_data->nr_irqs) {
> > + virq = irq_find_mapping(msi_data->parent, (31 - pos));
> > + if (virq)
> > + generic_handle_irq(virq);
> > + }
> > +
> > + chained_irq_exit(irq_desc_get_chip(desc), desc); }
> > +
> > +static int ls_scfg_msi_domains_init(struct ls_scfg_msi *msi_data) {
> > + /* Initialize MSI domain parent */
> > + msi_data->parent = irq_domain_add_linear(NULL,
> > + msi_data->nr_irqs,
> > + &ls_scfg_msi_domain_ops,
> > + msi_data);
> > + if (!msi_data->parent) {
> > + dev_err(&msi_data->pdev->dev, "failed to create IRQ domain\n");
> > + return -ENOMEM;
> > + }
> > +
> > + msi_data->msi_domain = pci_msi_create_irq_domain(
> > + of_node_to_fwnode(msi_data->pdev->dev.of_node),
> > + &ls_scfg_msi_domain_info,
> > + msi_data->parent);
> > + if (!msi_data->msi_domain) {
> > + dev_err(&msi_data->pdev->dev, "failed to create MSI domain\n");
> > + irq_domain_remove(msi_data->parent);
> > + return -ENOMEM;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int ls_scfg_msi_probe(struct platform_device *pdev) {
> > + struct ls_scfg_msi *msi_data;
> > + struct resource *res;
> > + int ret;
> > +
> > + msi_data = devm_kzalloc(&pdev->dev, sizeof(*msi_data), GFP_KERNEL);
> > + if (!msi_data)
> > + return -ENOMEM;
> > +
> > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > + msi_data->regs = devm_ioremap_resource(&pdev->dev, res);
> > + if (IS_ERR(msi_data->regs)) {
> > + dev_err(&pdev->dev, "failed to initialize 'regs'\n");
> > + return PTR_ERR(msi_data->regs);
> > + }
> > + msi_data->msiir_addr = res->start;
> > +
> > + msi_data->irq = platform_get_irq(pdev, 0);
> > + if (msi_data->irq <= 0) {
> > + dev_err(&pdev->dev, "failed to get MSI irq\n");
> > + return -ENODEV;
> > + }
> > +
> > + msi_data->pdev = pdev;
> > + msi_data->nr_irqs = MSI_MAX_IRQS;
>
> So this is hardcoded, always. Why do you need a nr_irqs variable at all?
[Lian Minghuan-B31939] Currently, nr_irqs is always 32, but in the future, the MSI controller may be extended to support more IRQs.
And, we may set nr_irqs the value of less than 32 to reserve some IRQs for special usage. So nr_irqs can bring flexibility
>
> > + spin_lock_init(&msi_data->lock);
> > +
> > + ret = ls_scfg_msi_domains_init(msi_data);
> > + if (ret)
> > + return ret;
> > +
> > + irq_set_chained_handler_and_data(msi_data->irq,
> > + ls_scfg_msi_irq_handler,
> > + msi_data);
> > +
> > + platform_set_drvdata(pdev, msi_data);
> > +
> > + return 0;
> > +}
> > +
> > +static int ls_scfg_msi_remove(struct platform_device *pdev) {
> > + struct ls_scfg_msi *msi_data = platform_get_drvdata(pdev);
> > +
> > + irq_set_chained_handler_and_data(msi_data->irq, NULL, NULL);
> > +
> > + irq_domain_remove(msi_data->msi_domain);
> > + irq_domain_remove(msi_data->parent);
> > +
> > + platform_set_drvdata(pdev, NULL);
> > +
> > + return 0;
> > +}
> > +
> > +static const struct of_device_id ls_scfg_msi_id[] = {
> > + { .compatible = "fsl,1s1021a-msi", },
> > + { .compatible = "fsl,1s1043a-msi", },
> > + {},
> > +};
> > +
> > +static struct platform_driver ls_scfg_msi_driver = {
> > + .driver = {
> > + .name = "ls-scfg-msi",
> > + .of_match_table = ls_scfg_msi_id,
> > + },
> > + .probe = ls_scfg_msi_probe,
> > + .remove = ls_scfg_msi_remove,
> > +};
> > +
> > +module_platform_driver(ls_scfg_msi_driver);
> > +
> > +MODULE_AUTHOR("Minghuan Lian <Minghuan.Lian at nxp.com>");
> > +MODULE_DESCRIPTION("NXP Layerscape SCFG MSI controller driver");
> > +MODULE_LICENSE("GPL v2");
> >
>
> Thanks,
>
> M.
> --
> Jazz is not dead. It just smells funny...
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