cdx: add support for bus mastering

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 <nipun.gupta@amd.com>
Reviewed-by: Pieter Jansen van Vuuren <pieter.jansen-van-vuuren@amd.com>
Link: https://lore.kernel.org/r/20230915045423.31630-1-nipun.gupta@amd.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/cdx/cdx.c b/drivers/cdx/cdx.c
index d2cad4c670a0734c883b4e326480b52edd8a4097..9efb7584f9529aa896252dedfd0ffed78b839cc9 100644 (file)
--- 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 bb4ae7970e215152b33ed050f141e02d3fc9a825..7828dac8edb1401cf253afbbe7f766746f3b5610 100644 (file)
--- a/drivers/cdx/controller/cdx_controller.c
+++ b/drivers/cdx/controller/cdx_controller.c
@@ -56,6 +56,10 @@ 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 0158f26533dd4a408872ac3f964d723c96cd5683..fc82435d5deaef5437954b3039893f975b249be7 100644 (file)
--- 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 7440ace5539a32e04e3eef926351ab363225ae21..a448d6581eb45abf491cd4489e34366c6923d930 100644 (file)
--- 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 bead71b7bc7380af36d42063a054a4c40b447314..8320ec3b9e373e4ed5c3d62755bdec795e81e2b4 100644 (file)
--- 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_ */