> -----Original Message-----
> From: Marc Zyngier <maz@xxxxxxxxxx>
> Sent: Thursday, July 21, 2022 2:57 AM
> To: Frank Li <frank.li@xxxxxxx>
> Cc: jdmason@xxxxxxxx; tglx@xxxxxxxxxxxxx; robh+dt@xxxxxxxxxx;
> krzysztof.kozlowski+dt@xxxxxxxxxx; shawnguo@xxxxxxxxxx;
> s.hauer@xxxxxxxxxxxxxx; kw@xxxxxxxxx; bhelgaas@xxxxxxxxxx;
> kernel@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx; Peng Fan
> <peng.fan@xxxxxxx>; Aisheng Dong <aisheng.dong@xxxxxxx>;
> kernel@xxxxxxxxxxxxxx; festevam@xxxxxxxxx; dl-linux-imx <linux-
> imx@xxxxxxx>; kishon@xxxxxx; lorenzo.pieralisi@xxxxxxx;
> ntb@xxxxxxxxxxxxxxx
> Subject: [EXT] Re: [PATCH v3 2/4] irqchip: imx mu worked as msi controller
>
> Caution: EXT Email
>
> On Wed, 20 Jul 2022 22:30:34 +0100,
> Frank Li <Frank.Li@xxxxxxx> wrote:
> >
> > MU support generate irq by write data to a register.
> > This patch make mu worked as msi controller.
> > So MU can do doorbell by using standard msi api.
> >
> > Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
> > ---
> > drivers/irqchip/Kconfig | 7 +
> > drivers/irqchip/Makefile | 1 +
> > drivers/irqchip/irq-imx-mu-msi.c | 462
> +++++++++++++++++++++++++++++++
> > 3 files changed, 470 insertions(+)
> > create mode 100644 drivers/irqchip/irq-imx-mu-msi.c
> >
> > diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> > index 5e4e50122777d..4599471d880c0 100644
> > --- a/drivers/irqchip/Kconfig
> > +++ b/drivers/irqchip/Kconfig
> > @@ -470,6 +470,13 @@ config IMX_INTMUX
> > help
> > Support for the i.MX INTMUX interrupt multiplexer.
> >
> > +config IMX_MU_MSI
> > + bool "i.MX MU work as MSI controller"
> > + default y if ARCH_MXC
> > + select IRQ_DOMAIN
> > + help
> > + MU work as MSI controller to do general doorbell
> > +
> > config LS1X_IRQ
> > bool "Loongson-1 Interrupt Controller"
> > depends on MACH_LOONGSON32
> > diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> > index 5d8e21d3dc6d8..870423746c783 100644
> > --- a/drivers/irqchip/Makefile
> > +++ b/drivers/irqchip/Makefile
> > @@ -98,6 +98,7 @@ obj-$(CONFIG_RISCV_INTC) += irq-riscv-intc.o
> > obj-$(CONFIG_SIFIVE_PLIC) += irq-sifive-plic.o
> > obj-$(CONFIG_IMX_IRQSTEER) += irq-imx-irqsteer.o
> > obj-$(CONFIG_IMX_INTMUX) += irq-imx-intmux.o
> > +obj-$(CONFIG_IMX_MU_MSI) += irq-imx-mu-msi.o
> > obj-$(CONFIG_MADERA_IRQ) += irq-madera.o
> > obj-$(CONFIG_LS1X_IRQ) += irq-ls1x.o
> > obj-$(CONFIG_TI_SCI_INTR_IRQCHIP) += irq-ti-sci-intr.o
> > diff --git a/drivers/irqchip/irq-imx-mu-msi.c b/drivers/irqchip/irq-imx-mu-
> msi.c
> > new file mode 100644
> > index 0000000000000..8277dba857759
> > --- /dev/null
> > +++ b/drivers/irqchip/irq-imx-mu-msi.c
> > @@ -0,0 +1,462 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * NXP MU worked as MSI controller
> > + *
> > + * Copyright (c) 2018 Pengutronix, Oleksij Rempel
> <o.rempel@xxxxxxxxxxxxxx>
> > + * Copyright 2022 NXP
> > + * Frank Li <Frank.Li@xxxxxxx>
> > + * Peng Fan <peng.fan@xxxxxxx>
> > + *
> > + * Based on drivers/mailbox/imx-mailbox.c
> > + */
> > +#include <linux/clk.h>
> > +#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/irqchip.h>
> > +#include <linux/irqdomain.h>
> > +#include <linux/of_irq.h>
> > +#include <linux/of_pci.h>
> > +#include <linux/of_platform.h>
> > +#include <linux/spinlock.h>
> > +#include <linux/dma-iommu.h>
> > +#include <linux/pm_runtime.h>
> > +#include <linux/pm_domain.h>
> > +
> > +
> > +#define IMX_MU_CHANS 4
> > +
> > +enum imx_mu_xcr {
> > + IMX_MU_GIER,
> > + IMX_MU_GCR,
> > + IMX_MU_TCR,
> > + IMX_MU_RCR,
> > + IMX_MU_xCR_MAX,
> > +};
> > +
> > +enum imx_mu_xsr {
> > + IMX_MU_SR,
> > + IMX_MU_GSR,
> > + IMX_MU_TSR,
> > + IMX_MU_RSR,
> > +};
> > +
> > +enum imx_mu_type {
> > + IMX_MU_V1 = BIT(0),
> > + IMX_MU_V2 = BIT(1),
> > + IMX_MU_V2_S4 = BIT(15),
> > +};
> > +
> > +/* Receive Interrupt Enable */
> > +#define IMX_MU_xCR_RIEn(type, x) (type & IMX_MU_V2 ? BIT(x) : BIT(24
> + (3 - (x))))
> > +#define IMX_MU_xSR_RFn(type, x) (type & IMX_MU_V2 ? BIT(x) : BIT(24 +
> (3 - (x))))
> > +
> > +struct imx_mu_dcfg {
> > + enum imx_mu_type type;
> > + u32 xTR; /* Transmit Register0 */
> > + u32 xRR; /* Receive Register0 */
> > + u32 xSR[4]; /* Status Registers */
> > + u32 xCR[4]; /* Control Registers */
> > +};
> > +
> > +struct imx_mu_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;
> > + const struct imx_mu_dcfg *cfg;
> > + unsigned long used;
> > + u32 gic_irq;
> > + struct clk *clk;
> > + struct device *pd_a;
> > + struct device *pd_b;
> > + struct device_link *pd_link_a;
> > + struct device_link *pd_link_b;
> > +};
> > +
> > +static void imx_mu_write(struct imx_mu_msi *msi_data, u32 val, u32 offs)
> > +{
> > + iowrite32(val, msi_data->regs + offs);
> > +}
> > +
> > +static u32 imx_mu_read(struct imx_mu_msi *msi_data, u32 offs)
> > +{
> > + return ioread32(msi_data->regs + offs);
> > +}
> > +
> > +static u32 imx_mu_xcr_rmw(struct imx_mu_msi *msi_data, enum
> imx_mu_xcr type, u32 set, u32 clr)
> > +{
> > + unsigned long flags;
> > + u32 val;
> > +
> > + spin_lock_irqsave(&msi_data->lock, flags);
> > + val = imx_mu_read(msi_data, msi_data->cfg->xCR[type]);
> > + val &= ~clr;
> > + val |= set;
> > + imx_mu_write(msi_data, val, msi_data->cfg->xCR[type]);
> > + spin_unlock_irqrestore(&msi_data->lock, flags);
> > +
> > + return val;
> > +}
> > +
> > +static void imx_mu_msi_mask_irq(struct irq_data *data)
> > +{
> > + struct imx_mu_msi *msi_data = irq_data_get_irq_chip_data(data-
> >parent_data);
>
> Urgh... No. Please don't go poking into the *parent* stuff. Implement
> the masking at the parent level, and use irq_chip_mask_parent() for
> this level, unless you can explain why you can't do otherwise.
>
> > +
> > + imx_mu_xcr_rmw(msi_data, IMX_MU_RCR, 0,
> IMX_MU_xCR_RIEn(msi_data->cfg->type, data->hwirq));
>
> How about making this readable and move the dereference inside the macro?
>
> > +}
> > +
> > +static void imx_mu_msi_unmask_irq(struct irq_data *data)
> > +{
> > + struct imx_mu_msi *msi_data = irq_data_get_irq_chip_data(data-
> >parent_data);
> > +
> > + imx_mu_xcr_rmw(msi_data, IMX_MU_RCR,
> IMX_MU_xCR_RIEn(msi_data->cfg->type, data->hwirq), 0);
> > +}
> > +
> > +static struct irq_chip imx_mu_msi_irq_chip = {
> > + .name = "MU-MSI",
> > + .irq_mask = imx_mu_msi_mask_irq,
> > + .irq_unmask = imx_mu_msi_unmask_irq,
> > +};
> > +
> > +static struct msi_domain_ops its_pmsi_ops = {
> > +};
>
> What does this have to do with the ITS?
Without this, it will be crashed as access 0 address.
>
> > +
> > +static struct msi_domain_info imx_mu_msi_domain_info = {
> > + .flags = (MSI_FLAG_USE_DEF_DOM_OPS |
> > + MSI_FLAG_USE_DEF_CHIP_OPS |
> > + MSI_FLAG_PCI_MSIX),
>
> What does PCI_MSIX mean in this context? I really wish you used
> copy/paste a bit more carefully.
>
> > + .ops = &its_pmsi_ops,
> > + .chip = &imx_mu_msi_irq_chip,
> > +};
> > +
> > +static void imx_mu_msi_compose_msg(struct irq_data *data, struct
> msi_msg *msg)
> > +{
> > + struct imx_mu_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 + 4 * data-
> >hwirq);
>
> This is a horrible way of writing this. you should compute the address
> first, and then apply the address split.
>
> > + msg->data = data->hwirq;
> > +
> > + iommu_dma_compose_msi_msg(irq_data_get_msi_desc(data), msg);
> > +}
> > +
> > +static int imx_mu_msi_set_affinity(struct irq_data *irq_data,
> > + const struct cpumask *mask, bool force)
> > +
> > +{
> > + return IRQ_SET_MASK_OK;
> > +}
>
> Err... What effect does this have if you don't do anything?
[Frank Li] Without this, it will be crashed as access 0 address.
>
> > +
> > +static struct irq_chip imx_mu_msi_parent_chip = {
> > + .name = "MU",
> > + .irq_compose_msi_msg = imx_mu_msi_compose_msg,
> > + .irq_set_affinity = imx_mu_msi_set_affinity,
> > +};
> > +
> > +static int imx_mu_msi_domain_irq_alloc(struct irq_domain *domain,
> > + unsigned int virq,
> > + unsigned int nr_irqs,
> > + void *args)
> > +{
> > + struct imx_mu_msi *msi_data = domain->host_data;
> > + msi_alloc_info_t *info = args;
> > + int pos, err = 0;
> > +
> > + WARN_ON(nr_irqs != 1);
> > +
> > + spin_lock(&msi_data->lock);
>
> Interrupt fires after lock acquisition, handler masks the interrupt.
> Deadlock.
[Frank Li] you are right, it should be spin_lock_irqsave.
>
> > + pos = find_first_zero_bit(&msi_data->used, IMX_MU_CHANS);
> > + if (pos < IMX_MU_CHANS)
> > + __set_bit(pos, &msi_data->used);
> > + else
> > + err = -ENOSPC;
> > + spin_unlock(&msi_data->lock);
> > +
> > + if (err)
> > + return err;
> > +
> > + err = iommu_dma_prepare_msi(info->desc, msi_data->msiir_addr +
> pos * 4);
>
> Does this HW even have an IOMMU?
[Frank Li] we have a platform with iommu.
>
> > + if (err)
> > + return err;
> > +
> > + irq_domain_set_info(domain, virq, pos,
> > + &imx_mu_msi_parent_chip, msi_data,
> > + handle_simple_irq, NULL, NULL);
>
> This is an edge interrupt. Please handle it like one.
[Frank Li] Not sure what your means?
>
> > + return 0;
> > +}
> > +
> > +static void imx_mu_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 imx_mu_msi *msi_data = irq_data_get_irq_chip_data(d);
> > +
> > + spin_lock(&msi_data->lock);
>
> Same problem.
>
> > + __clear_bit(d->hwirq, &msi_data->used);
> > + spin_unlock(&msi_data->lock);
> > +}
> > +
> > +static const struct irq_domain_ops imx_mu_msi_domain_ops = {
> > + .alloc = imx_mu_msi_domain_irq_alloc,
> > + .free = imx_mu_msi_domain_irq_free,
> > +};
> > +
> > +static void imx_mu_msi_irq_handler(struct irq_desc *desc)
> > +{
> > + struct imx_mu_msi *msi_data = irq_desc_get_handler_data(desc);
> > + u32 status;
> > + int i;
> > +
> > + status = imx_mu_read(msi_data, msi_data->cfg->xSR[IMX_MU_RSR]);
> > +
> > + chained_irq_enter(irq_desc_get_chip(desc), desc);
> > + for (i = 0; i < IMX_MU_CHANS; i++) {
> > + if (status & IMX_MU_xSR_RFn(msi_data->cfg->type, i)) {
> > + imx_mu_read(msi_data, msi_data->cfg->xRR + i * 4);
> > + generic_handle_domain_irq(msi_data->parent, i);
>
> Why the parent? You must start at the top of the hierarchy.
>
> > + }
> > + }
> > + chained_irq_exit(irq_desc_get_chip(desc), desc);
>
> If your MSIs are a chained interrupt, why do you even provide an
> affinity setting callback?
[Frank Li] it will be crash if no affinity setting callback.
>
> > +}
> > +
> > +static int imx_mu_msi_domains_init(struct imx_mu_msi *msi_data)
> > +{
> > + /* Initialize MSI domain parent */
> > + msi_data->parent = irq_domain_add_linear(dev_of_node(&msi_data-
> >pdev->dev),
> > + IMX_MU_CHANS,
> > + &imx_mu_msi_domain_ops,
> > + msi_data);
>
> Use irq_domain_create_linear() instead.
>
> > + if (!msi_data->parent) {
> > + dev_err(&msi_data->pdev->dev, "failed to create IRQ domain\n");
> > + return -ENOMEM;
> > + }
> > +
> > + msi_data->msi_domain = platform_msi_create_irq_domain(
> > + of_node_to_fwnode(msi_data->pdev->dev.of_node),
> > + &imx_mu_msi_domain_info,
> > + msi_data->parent);
>
> And you don't get an error due to the fact that you use the same
> fwnode for both domains without overriding the domain bus token?
>
> > +
> > + 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;
> > + }
> > +
> > + irq_domain_set_pm_device(msi_data->parent, &msi_data->pdev-
> >dev);
>
> I really wonder why you both implementing a MSI domain if you are
> always bypassing it for absolutely everything... This completely
> nullifies the effect of this call, as no interrupt request will ever
> trigger the PM.
>
> > +
> > + return 0;
> > +}
> > +
> > +/* Register offset of different version MU IP */
> > +static const struct imx_mu_dcfg imx_mu_cfg_imx6sx = {
> > + .xTR = 0x0,
> > + .xRR = 0x10,
> > + .xSR = {0x20, 0x20, 0x20, 0x20},
> > + .xCR = {0x24, 0x24, 0x24, 0x24},
> > +};
> > +
> > +static const struct imx_mu_dcfg imx_mu_cfg_imx7ulp = {
> > + .xTR = 0x20,
> > + .xRR = 0x40,
> > + .xSR = {0x60, 0x60, 0x60, 0x60},
> > + .xCR = {0x64, 0x64, 0x64, 0x64},
> > +};
> > +
> > +static const struct imx_mu_dcfg imx_mu_cfg_imx8ulp = {
> > + .type = IMX_MU_V2,
> > + .xTR = 0x200,
> > + .xRR = 0x280,
> > + .xSR = {0xC, 0x118, 0x124, 0x12C},
> > + .xCR = {0x110, 0x114, 0x120, 0x128},
> > +};
> > +
> > +static const struct imx_mu_dcfg imx_mu_cfg_imx8ulp_s4 = {
> > +
> > + .type = IMX_MU_V2 | IMX_MU_V2_S4,
> > + .xTR = 0x200,
> > + .xRR = 0x280,
> > + .xSR = {0xC, 0x118, 0x124, 0x12C},
> > + .xCR = {0x110, 0x114, 0x120, 0x128},
> > +};
> > +
> > +static int __init imx_mu_of_init(struct device_node *dn,
> > + struct device_node *parent,
> > + const struct imx_mu_dcfg *cfg)
> > +{
> > + struct platform_device *pdev = of_find_device_by_node(dn);
> > + struct imx_mu_msi *msi_data, *priv;
> > + struct resource *res;
> > + struct device *dev;
> > + int ret;
> > +
> > + if (!pdev)
> > + return -ENODEV;
> > +
> > + dev = &pdev->dev;
> > +
> > + priv = msi_data = devm_kzalloc(&pdev->dev, sizeof(*msi_data),
> GFP_KERNEL);
> > + if (!msi_data)
> > + return -ENOMEM;
> > +
> > + msi_data->cfg = cfg;
> > +
> > + msi_data->regs = devm_platform_ioremap_resource_byname(pdev,
> "a");
> > + if (IS_ERR(msi_data->regs)) {
> > + dev_err(&pdev->dev, "failed to initialize 'regs'\n");
> > + return PTR_ERR(msi_data->regs);
> > + }
> > +
> > + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "b");
> > + if (!res)
> > + return -EIO;
> > +
> > + msi_data->msiir_addr = res->start + msi_data->cfg->xTR;
> > +
> > + msi_data->pdev = pdev;
> > +
> > + msi_data->gic_irq = platform_get_irq(msi_data->pdev, 0);
> > + if (msi_data->gic_irq <= 0)
> > + return -ENODEV;
> > +
> > + platform_set_drvdata(pdev, msi_data);
> > +
> > + msi_data->clk = devm_clk_get(dev, NULL);
> > + if (IS_ERR(msi_data->clk)) {
> > + if (PTR_ERR(msi_data->clk) != -ENOENT)
> > + return PTR_ERR(msi_data->clk);
> > +
> > + msi_data->clk = NULL;
> > + }
> > +
> > + ret = clk_prepare_enable(msi_data->clk);
> > + if (ret) {
> > + dev_err(dev, "Failed to enable clock\n");
> > + return ret;
> > + }
> > +
> > + priv->pd_a = dev_pm_domain_attach_by_name(dev, "a");
> > + if (IS_ERR(priv->pd_a))
> > + return PTR_ERR(priv->pd_a);
> > +
> > + priv->pd_link_a = device_link_add(dev, priv->pd_a,
> > + DL_FLAG_STATELESS |
> > + DL_FLAG_PM_RUNTIME |
> > + DL_FLAG_RPM_ACTIVE);
> > +
> > + if (!priv->pd_link_a) {
> > + dev_err(dev, "Failed to add device_link to mu a.\n");
> > + return -EINVAL;
> > + }
> > +
> > + priv->pd_b = dev_pm_domain_attach_by_name(dev, "b");
> > + if (IS_ERR(priv->pd_b))
> > + return PTR_ERR(priv->pd_b);
> > +
> > + priv->pd_link_b = device_link_add(dev, priv->pd_b,
> > + DL_FLAG_STATELESS |
> > + DL_FLAG_PM_RUNTIME |
> > + DL_FLAG_RPM_ACTIVE);
> > +
> > + if (!priv->pd_link_b) {
> > + dev_err(dev, "Failed to add device_link to mu a.\n");
> > + return -EINVAL;
> > + }
> > +
> > + ret = imx_mu_msi_domains_init(msi_data);
> > + if (ret)
> > + return ret;
> > +
> > + irq_set_chained_handler_and_data(msi_data->gic_irq,
> > + imx_mu_msi_irq_handler,
> > + msi_data);
> > +
> > + pm_runtime_enable(dev);
> > +
> > + ret = pm_runtime_get_sync(dev);
> > + if (ret < 0) {
> > + pm_runtime_put_noidle(dev);
> > + goto disable_runtime_pm;
> > + }
> > +
> > + ret = pm_runtime_put_sync(dev);
> > + if (ret < 0)
> > + goto disable_runtime_pm;
> > +
> > + clk_disable_unprepare(msi_data->clk);
>
> Why do you need to do all this dance?
>
> > +
> > + return 0;
> > +
> > +disable_runtime_pm:
> > + pm_runtime_disable(dev);
> > + clk_disable_unprepare(msi_data->clk);
> > +
> > + return ret;
> > +}
> > +
> > +static int __maybe_unused imx_mu_runtime_suspend(struct device *dev)
> > +{
> > + struct imx_mu_msi *priv = dev_get_drvdata(dev);
> > +
> > + clk_disable_unprepare(priv->clk);
> > +
> > + return 0;
> > +}
> > +
> > +static int __maybe_unused imx_mu_runtime_resume(struct device *dev)
> > +{
> > + struct imx_mu_msi *priv = dev_get_drvdata(dev);
> > + int ret;
> > +
> > + ret = clk_prepare_enable(priv->clk);
> > + if (ret)
> > + dev_err(dev, "failed to enable clock\n");
> > +
> > + return ret;
> > +}
> > +
> > +static const struct dev_pm_ops imx_mu_pm_ops = {
> > + SET_RUNTIME_PM_OPS(imx_mu_runtime_suspend,
> > + imx_mu_runtime_resume, NULL)
> > +};
> > +
> > +static int __init imx_mu_imx7ulp_of_init(struct device_node *dn,
> > + struct device_node *parent)
> > +{
> > + return imx_mu_of_init(dn, parent, &imx_mu_cfg_imx7ulp);
> > +}
> > +
> > +static int __init imx_mu_imx6sx_of_init(struct device_node *dn,
> > + struct device_node *parent)
> > +{
> > + return imx_mu_of_init(dn, parent, &imx_mu_cfg_imx6sx);
> > +}
> > +
> > +static int __init imx_mu_imx8ulp_of_init(struct device_node *dn,
> > + struct device_node *parent)
> > +{
> > + return imx_mu_of_init(dn, parent, &imx_mu_cfg_imx8ulp);
> > +}
> > +
> > +static int __init imx_mu_imx8ulp_s4_of_init(struct device_node *dn,
> > + struct device_node *parent)
> > +{
> > + return imx_mu_of_init(dn, parent, &imx_mu_cfg_imx8ulp_s4);
> > +}
> > +
> > +IRQCHIP_PLATFORM_DRIVER_BEGIN(imx_mu_msi)
> > +IRQCHIP_MATCH("fsl,imx7ulp-mu-msi", imx_mu_imx7ulp_of_init)
> > +IRQCHIP_MATCH("fsl,imx6sx-mu-msi", imx_mu_imx6sx_of_init)
> > +IRQCHIP_MATCH("fsl,imx8ulp-mu-msi", imx_mu_imx8ulp_of_init)
> > +IRQCHIP_MATCH("fsl,imx8ulp-mu-msi-s4", imx_mu_imx8ulp_s4_of_init)
> > +IRQCHIP_PLATFORM_DRIVER_END(imx_mu_msi, .pm =
> &imx_mu_pm_ops)
> > +
> > +
> > +MODULE_AUTHOR("Frank Li <Frank.Li@xxxxxxx>");
> > +MODULE_DESCRIPTION("Freescale MU work as MSI controller driver");
> > +MODULE_LICENSE("GPL");
>
> M.
>
> --
> Without deviation from the norm, progress is not possible.
