[AMD Official Use Only - General]

-----Original Message-----
From: Greg KH <gregkh@linuxfoundation.org>
Sent: Wednesday, August 3, 2022 6:03 PM
To: Gupta, Nipun <Nipun.Gupta@amd.com>
Cc: linux-kernel@vger.kernel.org; linux-arm-kernel@lists.infradead.org;
rafael@kernel.org; maz@kernel.org; tglx@linutronix.de; okaya@kernel.org;
Anand, Harpreet [off-list ref]; Simek, Michal
[off-list ref]; Agarwal, Nikhil [off-list ref]
Subject: Re: [RFC PATCH 1/2] irqchip: cdx-bus: add cdx-MSI domain with gic-its
domain as parent

On Wed, Aug 03, 2022 at 05:56:54PM +0530, Nipun Gupta wrote:

quoted

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

quoted

 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

quoted

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),

quoted

+     .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", },
+     {},
+};
+
+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);

When drivers work properly, they should be quiet.

Also, when drivers print lines to the kernel log, they need to use the
dev_*() calls, not "raw" pr_*() calls please.

Totally agree on this.
Will be updated in the formal series.

Thanks,
Nipun

thanks,

greg k-h

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