cdx: add device attributes

Create sysfs entry for CDX devices.

Sysfs entries provided in each of the CDX device detected by
the CDX controller
 - vendor id
 - device id
 - remove
 - reset of the device.
 - driver override

Signed-off-by: Puneet Gupta <puneet.gupta@amd.com>
Signed-off-by: Nipun Gupta <nipun.gupta@amd.com>
Signed-off-by: Tarak Reddy <tarak.reddy@amd.com>
Reviewed-by: Pieter Jansen van Vuuren <pieter.jansen-van-vuuren@amd.com>
Tested-by: Nikhil Agarwal <nikhil.agarwal@amd.com>
Link: https://lore.kernel.org/r/20230313132636.31850-8-nipun.gupta@amd.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

4 files changed, 170 insertions, 0 deletions

diff --git a/drivers/cdx/cdx.c b/drivers/cdx/cdx.c
index 6b162bbb9b25..67c32cb2c006 100644
--- a/drivers/cdx/cdx.c
+++ b/drivers/cdx/cdx.c
@@ -72,6 +72,39 @@
 static DEFINE_XARRAY_ALLOC(cdx_controllers);
 
 /**
+ * cdx_dev_reset - Reset a CDX device
+ * @dev: CDX device
+ *
+ * Return: -errno on failure, 0 on success.
+ */
+int cdx_dev_reset(struct device *dev)
+{
+	struct cdx_device *cdx_dev = to_cdx_device(dev);
+	struct cdx_controller *cdx = cdx_dev->cdx;
+	struct cdx_device_config dev_config = {0};
+	struct cdx_driver *cdx_drv;
+	int ret;
+
+	cdx_drv = to_cdx_driver(dev->driver);
+	/* Notify driver that device is being reset */
+	if (cdx_drv && cdx_drv->reset_prepare)
+		cdx_drv->reset_prepare(cdx_dev);
+
+	dev_config.type = CDX_DEV_RESET_CONF;
+	ret = cdx->ops->dev_configure(cdx, cdx_dev->bus_num,
+				      cdx_dev->dev_num, &dev_config);
+	if (ret)
+		dev_err(dev, "cdx device reset failed\n");
+
+	/* Notify driver that device reset is complete */
+	if (cdx_drv && cdx_drv->reset_done)
+		cdx_drv->reset_done(cdx_dev);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(cdx_dev_reset);
+
+/**
  * cdx_unregister_device - Unregister a CDX device
  * @dev: CDX device
  * @data: This is always passed as NULL, and is not used in this API,
@@ -237,6 +270,99 @@ static int cdx_dma_configure(struct device *dev)
 	return 0;
 }
 
+/* show configuration fields */
+#define cdx_config_attr(field, format_string)	\
+static ssize_t	\
+field##_show(struct device *dev, struct device_attribute *attr, char *buf)	\
+{	\
+	struct cdx_device *cdx_dev = to_cdx_device(dev);	\
+	return sysfs_emit(buf, format_string, cdx_dev->field);	\
+}	\
+static DEVICE_ATTR_RO(field)
+
+cdx_config_attr(vendor, "0x%04x\n");
+cdx_config_attr(device, "0x%04x\n");
+
+static ssize_t remove_store(struct device *dev,
+			    struct device_attribute *attr,
+			    const char *buf, size_t count)
+{
+	bool val;
+
+	if (kstrtobool(buf, &val) < 0)
+		return -EINVAL;
+
+	if (!val)
+		return -EINVAL;
+
+	if (device_remove_file_self(dev, attr)) {
+		int ret;
+
+		ret = cdx_unregister_device(dev, NULL);
+		if (ret)
+			return ret;
+	}
+
+	return count;
+}
+static DEVICE_ATTR_WO(remove);
+
+static ssize_t reset_store(struct device *dev, struct device_attribute *attr,
+			   const char *buf, size_t count)
+{
+	bool val;
+	int ret;
+
+	if (kstrtobool(buf, &val) < 0)
+		return -EINVAL;
+
+	if (!val)
+		return -EINVAL;
+
+	ret = cdx_dev_reset(dev);
+	if (ret)
+		return ret;
+
+	return count;
+}
+static DEVICE_ATTR_WO(reset);
+
+static ssize_t driver_override_store(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t count)
+{
+	struct cdx_device *cdx_dev = to_cdx_device(dev);
+	int ret;
+
+	if (WARN_ON(dev->bus != &cdx_bus_type))
+		return -EINVAL;
+
+	ret = driver_set_override(dev, &cdx_dev->driver_override, buf, count);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static ssize_t driver_override_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	struct cdx_device *cdx_dev = to_cdx_device(dev);
+
+	return sysfs_emit(buf, "%s\n", cdx_dev->driver_override);
+}
+static DEVICE_ATTR_RW(driver_override);
+
+static struct attribute *cdx_dev_attrs[] = {
+	&dev_attr_remove.attr,
+	&dev_attr_reset.attr,
+	&dev_attr_vendor.attr,
+	&dev_attr_device.attr,
+	&dev_attr_driver_override.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(cdx_dev);
+
 static ssize_t rescan_store(struct bus_type *bus,
 			    const char *buf, size_t count)
 {
@@ -280,6 +406,7 @@ struct bus_type cdx_bus_type = {
 	.shutdown	= cdx_shutdown,
 	.dma_configure	= cdx_dma_configure,
 	.bus_groups	= cdx_bus_groups,
+	.dev_groups	= cdx_dev_groups,
 };
 EXPORT_SYMBOL_GPL(cdx_bus_type);
 
diff --git a/drivers/cdx/controller/cdx_controller.c b/drivers/cdx/controller/cdx_controller.c
index 0d1826980935..dc52f95f8978 100644
--- a/drivers/cdx/controller/cdx_controller.c
+++ b/drivers/cdx/controller/cdx_controller.c
@@ -45,6 +45,23 @@ void cdx_rpmsg_pre_remove(struct cdx_controller *cdx)
 	cdx_mcdi_wait_for_quiescence(cdx->priv, MCDI_RPC_TIMEOUT);
 }
 
+static int cdx_configure_device(struct cdx_controller *cdx,
+				u8 bus_num, u8 dev_num,
+				struct cdx_device_config *dev_config)
+{
+	int ret = 0;
+
+	switch (dev_config->type) {
+	case CDX_DEV_RESET_CONF:
+		ret = cdx_mcdi_reset_device(cdx->priv, bus_num, dev_num);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
 static int cdx_scan_devices(struct cdx_controller *cdx)
 {
 	struct cdx_mcdi *cdx_mcdi = cdx->priv;
@@ -104,6 +121,7 @@ static int cdx_scan_devices(struct cdx_controller *cdx)
 
 static struct cdx_ops cdx_ops = {
 	.scan		= cdx_scan_devices,
+	.dev_configure	= cdx_configure_device,
 };
 
 static int xlnx_cdx_probe(struct platform_device *pdev)
diff --git a/drivers/cdx/controller/mcdi_functions.c b/drivers/cdx/controller/mcdi_functions.c
index 012b52881dd5..0158f26533dd 100644
--- a/drivers/cdx/controller/mcdi_functions.c
+++ b/drivers/cdx/controller/mcdi_functions.c
@@ -123,3 +123,17 @@ int cdx_mcdi_get_dev_config(struct cdx_mcdi *cdx,
 
 	return 0;
 }
+
+int cdx_mcdi_reset_device(struct cdx_mcdi *cdx, u8 bus_num, u8 dev_num)
+{
+	MCDI_DECLARE_BUF(inbuf, MC_CMD_CDX_DEVICE_RESET_IN_LEN);
+	int ret;
+
+	MCDI_SET_DWORD(inbuf, CDX_DEVICE_RESET_IN_BUS, bus_num);
+	MCDI_SET_DWORD(inbuf, CDX_DEVICE_RESET_IN_DEVICE, dev_num);
+
+	ret = cdx_mcdi_rpc(cdx, MC_CMD_CDX_DEVICE_RESET, inbuf, sizeof(inbuf),
+			   NULL, 0, NULL);
+
+	return ret;
+}
diff --git a/drivers/cdx/controller/mcdi_functions.h b/drivers/cdx/controller/mcdi_functions.h
index 6bf5a4a0778f..7440ace5539a 100644
--- a/drivers/cdx/controller/mcdi_functions.h
+++ b/drivers/cdx/controller/mcdi_functions.h
@@ -47,4 +47,15 @@ int cdx_mcdi_get_dev_config(struct cdx_mcdi *cdx,
 			    u8 bus_num, u8 dev_num,
 			    struct cdx_dev_params *dev_params);
 
+/**
+ * cdx_mcdi_reset_device - Reset cdx device represented by bus_num:dev_num
+ * @cdx: pointer to MCDI interface.
+ * @bus_num: Bus number.
+ * @dev_num: Device number.
+ *
+ * Return: 0 on success, <0 on failure
+ */
+int cdx_mcdi_reset_device(struct cdx_mcdi *cdx,
+			  u8 bus_num, u8 dev_num);
+
 #endif /* CDX_MCDI_FUNCTIONS_H */