Messages in this thread | | | Date | Thu, 04 Aug 2022 09:49:50 +0100 | From | Marc Zyngier <> | Subject | Re: [RFC PATCH 1/2] irqchip: cdx-bus: add cdx-MSI domain with gic-its domain as parent |
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On Wed, 03 Aug 2022 13:26:54 +0100, Nipun Gupta <nipun.gupta@amd.com> wrote: > > Devices on cdx bus are dynamically detected and registered using > platform_device_register API. As these devices are not linked to > of node they need a separate MSI domain for handling device ID > to be provided to the GIC ITS domain. > > Signed-off-by: Nipun Gupta <nipun.gupta@amd.com> > Signed-off-by: Nikhil Agarwal <nikhil.agarwal@amd.com> > --- > CONFIG_CDX_BUS and device tree bindings for xlnx,cdx-controller-1.0 > would be added as part of CDX bus patches > > drivers/irqchip/Makefile | 1 + > drivers/irqchip/irq-gic-v3-its-cdx-msi.c | 113 +++++++++++++++++++++++ > include/linux/cdx/cdx.h | 15 +++ > 3 files changed, 129 insertions(+) > create mode 100644 drivers/irqchip/irq-gic-v3-its-cdx-msi.c > create mode 100644 include/linux/cdx/cdx.h > > diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile > index 5b67450a9538..623adb8a1f20 100644 > --- a/drivers/irqchip/Makefile > +++ b/drivers/irqchip/Makefile > @@ -115,3 +115,4 @@ obj-$(CONFIG_WPCM450_AIC) += irq-wpcm450-aic.o > obj-$(CONFIG_IRQ_IDT3243X) += irq-idt3243x.o > obj-$(CONFIG_APPLE_AIC) += irq-apple-aic.o > obj-$(CONFIG_MCHP_EIC) += irq-mchp-eic.o > +obj-$(CONFIG_CDX_BUS) += irq-gic-v3-its-cdx-msi.o > diff --git a/drivers/irqchip/irq-gic-v3-its-cdx-msi.c b/drivers/irqchip/irq-gic-v3-its-cdx-msi.c > new file mode 100644 > index 000000000000..eb17b74efdc5 > --- /dev/null > +++ b/drivers/irqchip/irq-gic-v3-its-cdx-msi.c > @@ -0,0 +1,113 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * AMD CDX bus driver MSI support > + * > + * Copyright(C) 2022 Xilinx Inc. > + */ > + > +#include <linux/irq.h> > +#include <linux/msi.h> > +#include <linux/of.h> > +#include <linux/of_address.h> > +#include <linux/of_device.h> > +#include <linux/of_irq.h> > +#include <linux/cdx/cdx.h> > + > +static struct irq_chip its_msi_irq_chip = { > + .name = "ITS-fMSI", > + .irq_mask = irq_chip_mask_parent, > + .irq_unmask = irq_chip_unmask_parent, > + .irq_eoi = irq_chip_eoi_parent, > + .irq_set_affinity = msi_domain_set_affinity > +}; > + > +static int its_cdx_msi_prepare(struct irq_domain *msi_domain, > + struct device *dev, > + int nvec, msi_alloc_info_t *info) > +{ > + struct msi_domain_info *msi_info; > + struct cdx_device_data *dev_data; > + u32 dev_id; > + > + dev_data = dev->platform_data; > + dev_id = dev_data->dev_id; > + > + /* Set the device Id to be passed to the GIC-ITS */ > + info->scratchpad[0].ul = dev_id; > + > + msi_info = msi_get_domain_info(msi_domain->parent); > + > + /* Allocate at least 32 MSIs, and always as a power of 2 */ > + nvec = max_t(int, 32, roundup_pow_of_two(nvec)); > + return msi_info->ops->msi_prepare(msi_domain->parent, dev, nvec, info); > +} > + > +static struct msi_domain_ops its_cdx_msi_ops __ro_after_init = { > + .msi_prepare = its_cdx_msi_prepare, > +}; > + > +static struct msi_domain_info its_cdx_msi_domain_info = { > + .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS), > + .ops = &its_cdx_msi_ops, > + .chip = &its_msi_irq_chip, > +}; > + > +static const struct of_device_id cdx_device_id[] = { > + {.compatible = "xlnx,cdx-controller-1.0", },
What is this? If this is supposed to represent am ITS, it really should say so.
> + {}, > +}; > + > +struct irq_domain *get_parent(struct fwnode_handle *handle) > +{ > + return irq_find_matching_fwnode(handle, DOMAIN_BUS_NEXUS); > +} > + > +static void __init its_cdx_msi_init_one(struct device_node *np, > + const char *name) > +{ > + struct irq_domain *parent; > + struct irq_domain *cdx_msi_domain; > + struct fwnode_handle *fwnode_handle; > + struct device_node *parent_node; > + > + parent_node = of_parse_phandle(np, "msi-parent", 0); > + > + parent = get_parent(of_node_to_fwnode(parent_node)); > + if (!parent || !msi_get_domain_info(parent)) { > + pr_err("%s: unable to locate ITS domain\n", name); > + return; > + } > + > + fwnode_handle = of_node_to_fwnode(np); > + cdx_msi_domain = platform_msi_create_irq_domain(fwnode_handle, > + &its_cdx_msi_domain_info, > + parent); > + if (!cdx_msi_domain) { > + pr_err("%s: unable to create cdx bus domain\n", name); > + return; > + } > + > + pr_info("cdx bus MSI: %s domain created\n", name); > +} > + > +static void __init its_cdx_of_msi_init(void) > +{ > + struct device_node *np; > + > + for (np = of_find_matching_node(NULL, cdx_device_id); np; > + np = of_find_matching_node(np, cdx_device_id)) { > + if (!of_device_is_available(np)) > + continue; > + > + its_cdx_msi_init_one(np, np->full_name); > + } > +} > + > +static int __init its_cdx_msi_init(void) > +{ > + its_cdx_of_msi_init(); > + > + return 0; > +} > + > +early_initcall(its_cdx_msi_init);
I really don't think we should have any more of this muck. Yes, the other busses are also doing that, but here's our chance to do something better.
Why can't the *bus* driver (I assume there is one) perform these tasks? It would really help if this patch was shown in context, because I have no idea how this fits in the grand scheme of things.
Thanks,
M.
-- Without deviation from the norm, progress is not possible.
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