Introduce cdx_set_master() and cdx_clear_master() APIs to support
enable and disable of bus mastering. Drivers need to use these APIs to
enable/disable DMAs from the CDX devices.
Signed-off-by: Nipun Gupta <[email protected]>
Reviewed-by: Pieter Jansen van Vuuren <[email protected]>
---
Changes v7->v8:
- Fix a comment in cdx_mcdi_ctrl_flag_set()
Changes v6->v7:
- None
Changes v5->v6:
- change cdx_clear_master() to int return type
Changes v4->v5:
- No change in this patch, patch 2/3 and patch 3/3 are updated
Changes v3->v4:
- Added user of the Bus master enable and disable APIs in patch 2/2.
There is no change in this patch.
Changes v2->v3:
- Changed return value from EOPNOTSUPP to -EOPNOTSUPP in
cdx_set_master()
Changes v1->v2:
- Replace bme with bus_master_enable
- Added check for dev_configure API callback
- remove un-necessary error prints
- changed conditional to if-else
- updated commit message to use 72 columns
drivers/cdx/cdx.c | 32 ++++++++++++++
drivers/cdx/controller/cdx_controller.c | 4 ++
drivers/cdx/controller/mcdi_functions.c | 58 +++++++++++++++++++++++++
drivers/cdx/controller/mcdi_functions.h | 13 ++++++
include/linux/cdx/cdx_bus.h | 18 ++++++++
5 files changed, 125 insertions(+)
diff --git a/drivers/cdx/cdx.c b/drivers/cdx/cdx.c
index d2cad4c670a0..9efb7584f952 100644
--- a/drivers/cdx/cdx.c
+++ b/drivers/cdx/cdx.c
@@ -182,6 +182,38 @@ cdx_match_id(const struct cdx_device_id *ids, struct cdx_device *dev)
return NULL;
}
+int cdx_set_master(struct cdx_device *cdx_dev)
+{
+ struct cdx_controller *cdx = cdx_dev->cdx;
+ struct cdx_device_config dev_config;
+ int ret = -EOPNOTSUPP;
+
+ dev_config.type = CDX_DEV_BUS_MASTER_CONF;
+ dev_config.bus_master_enable = true;
+ if (cdx->ops->dev_configure)
+ ret = cdx->ops->dev_configure(cdx, cdx_dev->bus_num,
+ cdx_dev->dev_num, &dev_config);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(cdx_set_master);
+
+int cdx_clear_master(struct cdx_device *cdx_dev)
+{
+ struct cdx_controller *cdx = cdx_dev->cdx;
+ struct cdx_device_config dev_config;
+ int ret = -EOPNOTSUPP;
+
+ dev_config.type = CDX_DEV_BUS_MASTER_CONF;
+ dev_config.bus_master_enable = false;
+ if (cdx->ops->dev_configure)
+ ret = cdx->ops->dev_configure(cdx, cdx_dev->bus_num,
+ cdx_dev->dev_num, &dev_config);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(cdx_clear_master);
+
/**
* cdx_bus_match - device to driver matching callback
* @dev: the cdx device to match against
diff --git a/drivers/cdx/controller/cdx_controller.c b/drivers/cdx/controller/cdx_controller.c
index dc52f95f8978..39aa569d8e07 100644
--- a/drivers/cdx/controller/cdx_controller.c
+++ b/drivers/cdx/controller/cdx_controller.c
@@ -55,6 +55,10 @@ static int cdx_configure_device(struct cdx_controller *cdx,
case CDX_DEV_RESET_CONF:
ret = cdx_mcdi_reset_device(cdx->priv, bus_num, dev_num);
break;
+ case CDX_DEV_BUS_MASTER_CONF:
+ ret = cdx_mcdi_bus_master_enable(cdx->priv, bus_num, dev_num,
+ dev_config->bus_master_enable);
+ break;
default:
ret = -EINVAL;
}
diff --git a/drivers/cdx/controller/mcdi_functions.c b/drivers/cdx/controller/mcdi_functions.c
index 0158f26533dd..6acd8fea4586 100644
--- a/drivers/cdx/controller/mcdi_functions.c
+++ b/drivers/cdx/controller/mcdi_functions.c
@@ -137,3 +137,61 @@ int cdx_mcdi_reset_device(struct cdx_mcdi *cdx, u8 bus_num, u8 dev_num)
return ret;
}
+
+static int cdx_mcdi_ctrl_flag_get(struct cdx_mcdi *cdx, u8 bus_num,
+ u8 dev_num, u32 *flags)
+{
+ MCDI_DECLARE_BUF(inbuf, MC_CMD_CDX_DEVICE_CONTROL_GET_IN_LEN);
+ MCDI_DECLARE_BUF(outbuf, MC_CMD_CDX_DEVICE_CONTROL_GET_OUT_LEN);
+ size_t outlen;
+ int ret;
+
+ MCDI_SET_DWORD(inbuf, CDX_DEVICE_CONTROL_GET_IN_BUS, bus_num);
+ MCDI_SET_DWORD(inbuf, CDX_DEVICE_CONTROL_GET_IN_DEVICE, dev_num);
+ ret = cdx_mcdi_rpc(cdx, MC_CMD_CDX_DEVICE_CONTROL_GET, inbuf,
+ sizeof(inbuf), outbuf, sizeof(outbuf), &outlen);
+ if (ret)
+ return ret;
+
+ if (outlen != MC_CMD_CDX_DEVICE_CONTROL_GET_OUT_LEN)
+ return -EIO;
+
+ *flags = MCDI_DWORD(outbuf, CDX_DEVICE_CONTROL_GET_OUT_FLAGS);
+
+ return 0;
+}
+
+static int cdx_mcdi_ctrl_flag_set(struct cdx_mcdi *cdx, u8 bus_num,
+ u8 dev_num, bool enable, int bit_pos)
+{
+ MCDI_DECLARE_BUF(inbuf, MC_CMD_CDX_DEVICE_CONTROL_SET_IN_LEN);
+ u32 flags;
+ int ret;
+
+ /*
+ * Get flags and then set/reset bit at bit_pos according to
+ * the input params.
+ */
+ ret = cdx_mcdi_ctrl_flag_get(cdx, bus_num, dev_num, &flags);
+ if (ret)
+ return ret;
+
+ flags = flags & (u32)(~(BIT(bit_pos)));
+ if (enable)
+ flags |= (1 << bit_pos);
+
+ MCDI_SET_DWORD(inbuf, CDX_DEVICE_CONTROL_SET_IN_BUS, bus_num);
+ MCDI_SET_DWORD(inbuf, CDX_DEVICE_CONTROL_SET_IN_DEVICE, dev_num);
+ MCDI_SET_DWORD(inbuf, CDX_DEVICE_CONTROL_SET_IN_FLAGS, flags);
+ ret = cdx_mcdi_rpc(cdx, MC_CMD_CDX_DEVICE_CONTROL_SET, inbuf,
+ sizeof(inbuf), NULL, 0, NULL);
+
+ return ret;
+}
+
+int cdx_mcdi_bus_master_enable(struct cdx_mcdi *cdx, u8 bus_num,
+ u8 dev_num, bool enable)
+{
+ return cdx_mcdi_ctrl_flag_set(cdx, bus_num, dev_num, enable,
+ MC_CMD_CDX_DEVICE_CONTROL_SET_IN_BUS_MASTER_ENABLE_LBN);
+}
diff --git a/drivers/cdx/controller/mcdi_functions.h b/drivers/cdx/controller/mcdi_functions.h
index 7440ace5539a..a448d6581eb4 100644
--- a/drivers/cdx/controller/mcdi_functions.h
+++ b/drivers/cdx/controller/mcdi_functions.h
@@ -58,4 +58,17 @@ int cdx_mcdi_get_dev_config(struct cdx_mcdi *cdx,
int cdx_mcdi_reset_device(struct cdx_mcdi *cdx,
u8 bus_num, u8 dev_num);
+/**
+ * cdx_mcdi_bus_master_enable - Set/Reset bus mastering for cdx device
+ * represented by bus_num:dev_num
+ * @cdx: pointer to MCDI interface.
+ * @bus_num: Bus number.
+ * @dev_num: Device number.
+ * @enable: Enable bus mastering if set, disable otherwise.
+ *
+ * Return: 0 on success, <0 on failure
+ */
+int cdx_mcdi_bus_master_enable(struct cdx_mcdi *cdx, u8 bus_num,
+ u8 dev_num, bool enable);
+
#endif /* CDX_MCDI_FUNCTIONS_H */
diff --git a/include/linux/cdx/cdx_bus.h b/include/linux/cdx/cdx_bus.h
index bead71b7bc73..8320ec3b9e37 100644
--- a/include/linux/cdx/cdx_bus.h
+++ b/include/linux/cdx/cdx_bus.h
@@ -21,11 +21,13 @@
struct cdx_controller;
enum {
+ CDX_DEV_BUS_MASTER_CONF,
CDX_DEV_RESET_CONF,
};
struct cdx_device_config {
u8 type;
+ bool bus_master_enable;
};
typedef int (*cdx_scan_cb)(struct cdx_controller *cdx);
@@ -170,4 +172,20 @@ extern struct bus_type cdx_bus_type;
*/
int cdx_dev_reset(struct device *dev);
+/**
+ * cdx_set_master - enables bus-mastering for CDX device
+ * @cdx_dev: the CDX device to enable
+ *
+ * Return: 0 for success, -errno on failure
+ */
+int cdx_set_master(struct cdx_device *cdx_dev);
+
+/**
+ * cdx_clear_master - disables bus-mastering for CDX device
+ * @cdx_dev: the CDX device to disable
+ *
+ * Return: 0 for success, -errno on failure
+ */
+int cdx_clear_master(struct cdx_device *cdx_dev);
+
#endif /* _CDX_BUS_H_ */
--
2.17.1
Support Bus master enable and disable on VFIO-CDX devices using
VFIO_DEVICE_FEATURE_BUS_MASTER flag over VFIO_DEVICE_FEATURE IOCTL.
Co-developed-by: Shubham Rohila <[email protected]>
Signed-off-by: Shubham Rohila <[email protected]>
Signed-off-by: Nipun Gupta <[email protected]>
---
Changes v7->v8:
- None
Changes v6->v7:
- Add check for BME in open, thus resulting in correct response
in feature probe.
- Set vdev_regions to NULL in case of error in vfio device open.
Changes v5->v6:
- Called CDX device reset at cdx_open_device()
Changes v4->v5:
- Use device feature IOCTL instead of adding a new VFIO IOCTL
for bus master feature.
Changes in v4:
- This patch is newly added which uses cdx_set_master() and
cdx_clear_master() APIs.
drivers/vfio/cdx/main.c | 57 +++++++++++++++++++++++++++++++++++++-
drivers/vfio/cdx/private.h | 2 ++
2 files changed, 58 insertions(+), 1 deletion(-)
diff --git a/drivers/vfio/cdx/main.c b/drivers/vfio/cdx/main.c
index c376a69d2db2..53ed8e6c499f 100644
--- a/drivers/vfio/cdx/main.c
+++ b/drivers/vfio/cdx/main.c
@@ -14,7 +14,7 @@ static int vfio_cdx_open_device(struct vfio_device *core_vdev)
container_of(core_vdev, struct vfio_cdx_device, vdev);
struct cdx_device *cdx_dev = to_cdx_device(core_vdev->dev);
int count = cdx_dev->res_count;
- int i;
+ int i, ret;
vdev->regions = kcalloc(count, sizeof(struct vfio_cdx_region),
GFP_KERNEL_ACCOUNT);
@@ -39,6 +39,17 @@ static int vfio_cdx_open_device(struct vfio_device *core_vdev)
if (!(cdx_dev->res[i].flags & IORESOURCE_READONLY))
vdev->regions[i].flags |= VFIO_REGION_INFO_FLAG_WRITE;
}
+ ret = cdx_dev_reset(core_vdev->dev);
+ if (ret) {
+ kfree(vdev->regions);
+ vdev->regions = NULL;
+ return ret;
+ }
+ ret = cdx_clear_master(cdx_dev);
+ if (ret)
+ vdev->flags &= ~BME_SUPPORT;
+ else
+ vdev->flags |= BME_SUPPORT;
return 0;
}
@@ -52,6 +63,49 @@ static void vfio_cdx_close_device(struct vfio_device *core_vdev)
cdx_dev_reset(core_vdev->dev);
}
+static int vfio_cdx_bm_ctrl(struct vfio_device *core_vdev, u32 flags,
+ void __user *arg, size_t argsz)
+{
+ size_t minsz =
+ offsetofend(struct vfio_device_feature_bus_master, op);
+ struct vfio_cdx_device *vdev =
+ container_of(core_vdev, struct vfio_cdx_device, vdev);
+ struct cdx_device *cdx_dev = to_cdx_device(core_vdev->dev);
+ struct vfio_device_feature_bus_master ops;
+ int ret;
+
+ if (!vdev->flags & BME_SUPPORT)
+ return -ENOTTY;
+
+ ret = vfio_check_feature(flags, argsz, VFIO_DEVICE_FEATURE_SET,
+ sizeof(ops));
+ if (ret != 1)
+ return ret;
+
+ if (copy_from_user(&ops, arg, minsz))
+ return -EFAULT;
+
+ switch (ops.op) {
+ case VFIO_DEVICE_FEATURE_CLEAR_MASTER:
+ return cdx_clear_master(cdx_dev);
+ case VFIO_DEVICE_FEATURE_SET_MASTER:
+ return cdx_set_master(cdx_dev);
+ default:
+ return -EINVAL;
+ }
+}
+
+static int vfio_cdx_ioctl_feature(struct vfio_device *device, u32 flags,
+ void __user *arg, size_t argsz)
+{
+ switch (flags & VFIO_DEVICE_FEATURE_MASK) {
+ case VFIO_DEVICE_FEATURE_BUS_MASTER:
+ return vfio_cdx_bm_ctrl(device, flags, arg, argsz);
+ default:
+ return -ENOTTY;
+ }
+}
+
static int vfio_cdx_ioctl_get_info(struct vfio_cdx_device *vdev,
struct vfio_device_info __user *arg)
{
@@ -169,6 +223,7 @@ static const struct vfio_device_ops vfio_cdx_ops = {
.open_device = vfio_cdx_open_device,
.close_device = vfio_cdx_close_device,
.ioctl = vfio_cdx_ioctl,
+ .device_feature = vfio_cdx_ioctl_feature,
.mmap = vfio_cdx_mmap,
.bind_iommufd = vfio_iommufd_physical_bind,
.unbind_iommufd = vfio_iommufd_physical_unbind,
diff --git a/drivers/vfio/cdx/private.h b/drivers/vfio/cdx/private.h
index 8bdc117ea88e..8e9d25913728 100644
--- a/drivers/vfio/cdx/private.h
+++ b/drivers/vfio/cdx/private.h
@@ -23,6 +23,8 @@ struct vfio_cdx_region {
struct vfio_cdx_device {
struct vfio_device vdev;
struct vfio_cdx_region *regions;
+ u32 flags;
+#define BME_SUPPORT BIT(0)
};
#endif /* VFIO_CDX_PRIVATE_H */
--
2.17.1
On Fri, 15 Sep 2023 10:24:21 +0530
Nipun Gupta <[email protected]> wrote:
> Introduce cdx_set_master() and cdx_clear_master() APIs to support
> enable and disable of bus mastering. Drivers need to use these APIs to
> enable/disable DMAs from the CDX devices.
>
> Signed-off-by: Nipun Gupta <[email protected]>
> Reviewed-by: Pieter Jansen van Vuuren <[email protected]>
> ---
Applied series to vfio next branch for v6.7. Thanks,
Alex
>
> Changes v7->v8:
> - Fix a comment in cdx_mcdi_ctrl_flag_set()
>
> Changes v6->v7:
> - None
>
> Changes v5->v6:
> - change cdx_clear_master() to int return type
>
> Changes v4->v5:
> - No change in this patch, patch 2/3 and patch 3/3 are updated
>
> Changes v3->v4:
> - Added user of the Bus master enable and disable APIs in patch 2/2.
> There is no change in this patch.
>
> Changes v2->v3:
> - Changed return value from EOPNOTSUPP to -EOPNOTSUPP in
> cdx_set_master()
>
> Changes v1->v2:
> - Replace bme with bus_master_enable
> - Added check for dev_configure API callback
> - remove un-necessary error prints
> - changed conditional to if-else
> - updated commit message to use 72 columns
>
> drivers/cdx/cdx.c | 32 ++++++++++++++
> drivers/cdx/controller/cdx_controller.c | 4 ++
> drivers/cdx/controller/mcdi_functions.c | 58 +++++++++++++++++++++++++
> drivers/cdx/controller/mcdi_functions.h | 13 ++++++
> include/linux/cdx/cdx_bus.h | 18 ++++++++
> 5 files changed, 125 insertions(+)
>
> diff --git a/drivers/cdx/cdx.c b/drivers/cdx/cdx.c
> index d2cad4c670a0..9efb7584f952 100644
> --- a/drivers/cdx/cdx.c
> +++ b/drivers/cdx/cdx.c
> @@ -182,6 +182,38 @@ cdx_match_id(const struct cdx_device_id *ids, struct cdx_device *dev)
> return NULL;
> }
>
> +int cdx_set_master(struct cdx_device *cdx_dev)
> +{
> + struct cdx_controller *cdx = cdx_dev->cdx;
> + struct cdx_device_config dev_config;
> + int ret = -EOPNOTSUPP;
> +
> + dev_config.type = CDX_DEV_BUS_MASTER_CONF;
> + dev_config.bus_master_enable = true;
> + if (cdx->ops->dev_configure)
> + ret = cdx->ops->dev_configure(cdx, cdx_dev->bus_num,
> + cdx_dev->dev_num, &dev_config);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(cdx_set_master);
> +
> +int cdx_clear_master(struct cdx_device *cdx_dev)
> +{
> + struct cdx_controller *cdx = cdx_dev->cdx;
> + struct cdx_device_config dev_config;
> + int ret = -EOPNOTSUPP;
> +
> + dev_config.type = CDX_DEV_BUS_MASTER_CONF;
> + dev_config.bus_master_enable = false;
> + if (cdx->ops->dev_configure)
> + ret = cdx->ops->dev_configure(cdx, cdx_dev->bus_num,
> + cdx_dev->dev_num, &dev_config);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(cdx_clear_master);
> +
> /**
> * cdx_bus_match - device to driver matching callback
> * @dev: the cdx device to match against
> diff --git a/drivers/cdx/controller/cdx_controller.c b/drivers/cdx/controller/cdx_controller.c
> index dc52f95f8978..39aa569d8e07 100644
> --- a/drivers/cdx/controller/cdx_controller.c
> +++ b/drivers/cdx/controller/cdx_controller.c
> @@ -55,6 +55,10 @@ static int cdx_configure_device(struct cdx_controller *cdx,
> case CDX_DEV_RESET_CONF:
> ret = cdx_mcdi_reset_device(cdx->priv, bus_num, dev_num);
> break;
> + case CDX_DEV_BUS_MASTER_CONF:
> + ret = cdx_mcdi_bus_master_enable(cdx->priv, bus_num, dev_num,
> + dev_config->bus_master_enable);
> + break;
> default:
> ret = -EINVAL;
> }
> diff --git a/drivers/cdx/controller/mcdi_functions.c b/drivers/cdx/controller/mcdi_functions.c
> index 0158f26533dd..6acd8fea4586 100644
> --- a/drivers/cdx/controller/mcdi_functions.c
> +++ b/drivers/cdx/controller/mcdi_functions.c
> @@ -137,3 +137,61 @@ int cdx_mcdi_reset_device(struct cdx_mcdi *cdx, u8 bus_num, u8 dev_num)
>
> return ret;
> }
> +
> +static int cdx_mcdi_ctrl_flag_get(struct cdx_mcdi *cdx, u8 bus_num,
> + u8 dev_num, u32 *flags)
> +{
> + MCDI_DECLARE_BUF(inbuf, MC_CMD_CDX_DEVICE_CONTROL_GET_IN_LEN);
> + MCDI_DECLARE_BUF(outbuf, MC_CMD_CDX_DEVICE_CONTROL_GET_OUT_LEN);
> + size_t outlen;
> + int ret;
> +
> + MCDI_SET_DWORD(inbuf, CDX_DEVICE_CONTROL_GET_IN_BUS, bus_num);
> + MCDI_SET_DWORD(inbuf, CDX_DEVICE_CONTROL_GET_IN_DEVICE, dev_num);
> + ret = cdx_mcdi_rpc(cdx, MC_CMD_CDX_DEVICE_CONTROL_GET, inbuf,
> + sizeof(inbuf), outbuf, sizeof(outbuf), &outlen);
> + if (ret)
> + return ret;
> +
> + if (outlen != MC_CMD_CDX_DEVICE_CONTROL_GET_OUT_LEN)
> + return -EIO;
> +
> + *flags = MCDI_DWORD(outbuf, CDX_DEVICE_CONTROL_GET_OUT_FLAGS);
> +
> + return 0;
> +}
> +
> +static int cdx_mcdi_ctrl_flag_set(struct cdx_mcdi *cdx, u8 bus_num,
> + u8 dev_num, bool enable, int bit_pos)
> +{
> + MCDI_DECLARE_BUF(inbuf, MC_CMD_CDX_DEVICE_CONTROL_SET_IN_LEN);
> + u32 flags;
> + int ret;
> +
> + /*
> + * Get flags and then set/reset bit at bit_pos according to
> + * the input params.
> + */
> + ret = cdx_mcdi_ctrl_flag_get(cdx, bus_num, dev_num, &flags);
> + if (ret)
> + return ret;
> +
> + flags = flags & (u32)(~(BIT(bit_pos)));
> + if (enable)
> + flags |= (1 << bit_pos);
> +
> + MCDI_SET_DWORD(inbuf, CDX_DEVICE_CONTROL_SET_IN_BUS, bus_num);
> + MCDI_SET_DWORD(inbuf, CDX_DEVICE_CONTROL_SET_IN_DEVICE, dev_num);
> + MCDI_SET_DWORD(inbuf, CDX_DEVICE_CONTROL_SET_IN_FLAGS, flags);
> + ret = cdx_mcdi_rpc(cdx, MC_CMD_CDX_DEVICE_CONTROL_SET, inbuf,
> + sizeof(inbuf), NULL, 0, NULL);
> +
> + return ret;
> +}
> +
> +int cdx_mcdi_bus_master_enable(struct cdx_mcdi *cdx, u8 bus_num,
> + u8 dev_num, bool enable)
> +{
> + return cdx_mcdi_ctrl_flag_set(cdx, bus_num, dev_num, enable,
> + MC_CMD_CDX_DEVICE_CONTROL_SET_IN_BUS_MASTER_ENABLE_LBN);
> +}
> diff --git a/drivers/cdx/controller/mcdi_functions.h b/drivers/cdx/controller/mcdi_functions.h
> index 7440ace5539a..a448d6581eb4 100644
> --- a/drivers/cdx/controller/mcdi_functions.h
> +++ b/drivers/cdx/controller/mcdi_functions.h
> @@ -58,4 +58,17 @@ int cdx_mcdi_get_dev_config(struct cdx_mcdi *cdx,
> int cdx_mcdi_reset_device(struct cdx_mcdi *cdx,
> u8 bus_num, u8 dev_num);
>
> +/**
> + * cdx_mcdi_bus_master_enable - Set/Reset bus mastering for cdx device
> + * represented by bus_num:dev_num
> + * @cdx: pointer to MCDI interface.
> + * @bus_num: Bus number.
> + * @dev_num: Device number.
> + * @enable: Enable bus mastering if set, disable otherwise.
> + *
> + * Return: 0 on success, <0 on failure
> + */
> +int cdx_mcdi_bus_master_enable(struct cdx_mcdi *cdx, u8 bus_num,
> + u8 dev_num, bool enable);
> +
> #endif /* CDX_MCDI_FUNCTIONS_H */
> diff --git a/include/linux/cdx/cdx_bus.h b/include/linux/cdx/cdx_bus.h
> index bead71b7bc73..8320ec3b9e37 100644
> --- a/include/linux/cdx/cdx_bus.h
> +++ b/include/linux/cdx/cdx_bus.h
> @@ -21,11 +21,13 @@
> struct cdx_controller;
>
> enum {
> + CDX_DEV_BUS_MASTER_CONF,
> CDX_DEV_RESET_CONF,
> };
>
> struct cdx_device_config {
> u8 type;
> + bool bus_master_enable;
> };
>
> typedef int (*cdx_scan_cb)(struct cdx_controller *cdx);
> @@ -170,4 +172,20 @@ extern struct bus_type cdx_bus_type;
> */
> int cdx_dev_reset(struct device *dev);
>
> +/**
> + * cdx_set_master - enables bus-mastering for CDX device
> + * @cdx_dev: the CDX device to enable
> + *
> + * Return: 0 for success, -errno on failure
> + */
> +int cdx_set_master(struct cdx_device *cdx_dev);
> +
> +/**
> + * cdx_clear_master - disables bus-mastering for CDX device
> + * @cdx_dev: the CDX device to disable
> + *
> + * Return: 0 for success, -errno on failure
> + */
> +int cdx_clear_master(struct cdx_device *cdx_dev);
> +
> #endif /* _CDX_BUS_H_ */