Re: [RFC PATCH 1/2] irqchip: cdx-bus: add cdx-MSI domain with gic-its domain as parent
From: Marc Zyngier <maz@kernel.org>
Date: 2022-08-04 08:50:13
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On Wed, 03 Aug 2022 13:26:54 +0100, Nipun Gupta [off-list ref] wrote:
quoted hunk ↗ jump to hunk
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.hdiff --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.odiff --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. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel