[RFC PATCH v2 3/6] bus/cdx: add cdx-MSI domain with gic-its domain as parent

Nipun Gupta
2022-08-17T15:06:40Z

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>
---
drivers/bus/cdx/Makefile | 2 +-
drivers/bus/cdx/cdx.c | 31 +++++++++++
drivers/bus/cdx/cdx.h | 16 ++++++
drivers/bus/cdx/cdx_msi_domain.c | 90 ++++++++++++++++++++++++++++++++
4 files changed, 138 insertions(+), 1 deletion(-)
create mode 100644 drivers/bus/cdx/cdx_msi_domain.c

diff --git a/drivers/bus/cdx/Makefile b/drivers/bus/cdx/Makefile
index c9cee5b6fa8a..5dc7874530f5 100644
--- a/drivers/bus/cdx/Makefile
+++ b/drivers/bus/cdx/Makefile
@@ -1,3 +1,3 @@
obj-$(CONFIG_CDX_BUS) += cdx-bus-device-driver.o

-cdx-bus-device-driver-objs := cdx.o
+cdx-bus-device-driver-objs := cdx.o cdx_msi_domain.o
diff --git a/drivers/bus/cdx/cdx.c b/drivers/bus/cdx/cdx.c
index f28329770af8..cd916ef5f2bc 100644
--- a/drivers/bus/cdx/cdx.c
+++ b/drivers/bus/cdx/cdx.c
@@ -15,7 +15,9 @@
#include <linux/of_platform.h>
#include <linux/dma-mapping.h>
#include <linux/property.h>
+#include <linux/msi.h>
#include <linux/cdx/cdx_bus.h>
+#include "cdx.h"

#include "cdx.h"

@@ -47,6 +49,8 @@ static int cdx_populate_one(struct platform_device *pdev_parent,

dev_data.bus_id = dev_params->bus_id;
dev_data.func_id = dev_params->func_id;
+ dev_data.dev_id = dev_params->msi_device_id;
+ dev_data.num_msi = dev_params->num_msi;

memset(&pdevinfo, 0, sizeof(pdevinfo));
pdevinfo.fwnode = swnode;
@@ -76,6 +80,10 @@ static int cdx_populate_one(struct platform_device *pdev_parent,
goto out;
}

+ /* Set the MSI domain */
+ dev_set_msi_domain(&new_pdev->dev,
+ irq_find_host(pdev_parent->dev.of_node));
+
return 0;

out:
@@ -109,8 +117,22 @@ static int cdx_bus_device_discovery(struct platform_device *pdev)
int num_cdx_bus = 0, num_cdx_func = 0;
int bus_id = 0, func_id = 0;
struct device_node *np = pdev->dev.of_node;
+ struct irq_domain *cdx_msi_domain;
int ret;

+ /* If CDX MSI domain is not created, create one. */
+ cdx_msi_domain = irq_find_host(pdev->dev.of_node);
+ if (!cdx_msi_domain) {
+ np = pdev->dev.of_node;
+
+ ret = cdx_msi_domain_init(&pdev->dev, np->full_name);
+ if (ret != 0) {
+ dev_err(&pdev->dev,
+ "cdx_msi_domain_init() failed: %d", ret);
+ return ret;
+ }
+ }
+
/* TODO: Get number of busses from firmware */
num_cdx_bus = 1;

@@ -144,7 +166,16 @@ static int cdx_bus_device_discovery(struct platform_device *pdev)
ret);
goto fail;
}
+ ret = of_map_id(np, req_id, "msi-map", "msi-map-mask",
+ NULL, &dev_params.msi_device_id);
+ if (ret != 0) {
+ dev_err(&pdev->dev,
+ "of_map_id failed for MSI: %d\n",
+ ret);
+ goto fail;
+ }

+ dev_params.num_msi = 2;
dev_params.dev_type_idx = 0;
dev_params.res_cnt = 1;

diff --git a/drivers/bus/cdx/cdx.h b/drivers/bus/cdx/cdx.h
index 7db8b06de9cd..da2c282d4d93 100644
--- a/drivers/bus/cdx/cdx.h
+++ b/drivers/bus/cdx/cdx.h
@@ -19,6 +19,8 @@ struct cdx_dev_params_t {
struct resource res[CDX_DEV_NUM_RESOURCES];
int res_cnt;
u32 stream_id;
+ u32 msi_device_id;
+ u32 num_msi;
};

/**
@@ -26,10 +28,24 @@ struct cdx_dev_params_t {
* CDX device.
* @bus_id: Bus ID for reset
* @func_id: Function ID for reset
+ * @dev_id: Device ID for MSI.
+ * @num_msi: Number of MSI supported by the device
*/
struct cdx_device_data {
u32 bus_id;
u32 func_id;
+ u32 dev_id;
+ u32 num_msi;
};

+/**
+ * cdx_msi_domain_init - Init the CDX bus MSI domain.
+ * @cbus_dev: Device of the CDX bus
+ * @name: Name to be assigned to the newly created domain
+ *
+ * Return 0 on success, <0 on failure
+ */
+int cdx_msi_domain_init(struct device *cdev_bus,
+ const char *name);
+
#endif /* _CDX_H_ */
diff --git a/drivers/bus/cdx/cdx_msi_domain.c b/drivers/bus/cdx/cdx_msi_domain.c
new file mode 100644
index 000000000000..44472ae02d1c
--- /dev/null
+++ b/drivers/bus/cdx/cdx_msi_domain.c
@@ -0,0 +1,90 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * CDX bus driver MSI support
+ *
+ * Copyright(c) 2022 Xilinx.
+ *
+ */
+
+#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 "cdx.h"
+
+static struct irq_chip cdx_msi_irq_chip = {
+ .name = "CDX-MSI",
+ .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 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;
+
+ /* Retrieve device ID from platform data */
+ 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 cdx_msi_ops __ro_after_init = {
+ .msi_prepare = cdx_msi_prepare,
+};
+
+static struct msi_domain_info cdx_msi_domain_info = {
+ .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS),
+ .ops = &cdx_msi_ops,
+ .chip = &cdx_msi_irq_chip,
+};
+
+int cdx_msi_domain_init(struct device *cbus_dev,
+ const char *name)
+{
+ struct irq_domain *parent;
+ struct irq_domain *cdx_msi_domain;
+ struct fwnode_handle *fwnode_handle;
+ struct device_node *parent_node;
+ struct device_node *np;
+
+ np = cbus_dev->of_node;
+ parent_node = of_parse_phandle(np, "msi-map", 1);
+
+ parent = irq_find_matching_fwnode(of_node_to_fwnode(parent_node),
+ DOMAIN_BUS_NEXUS);
+ if (!parent || !msi_get_domain_info(parent)) {
+ dev_err(cbus_dev, "%s: unable to locate ITS domain\n", name);
+ return -ENODEV;
+ }
+
+ fwnode_handle = of_node_to_fwnode(np);
+ cdx_msi_domain = platform_msi_create_irq_domain(fwnode_handle,
+ &cdx_msi_domain_info,
+ parent);
+ if (!cdx_msi_domain) {
+ dev_err(cbus_dev, "%s: unable to create cdx bus domain\n",
+ name);
+ return -1;
+ }
+
+ dev_info(cbus_dev, "cdx bus MSI: %s domain created\n", name);
+
+ return 0;
+}
--
2.25.1