uclass: cpu: Add new API to get udevice for current CPU

When running on SoC with multiple clusters, the boot CPU may
not be fixed, saying booting from cluster A or cluster B.
Add a API that can return the udevice for current boot CPU.
Cpu driver needs to implement is_current_cpu interface for this
feature, otherwise the API only returns the first udevice in
cpu uclass.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Ye Li <ye.li@nxp.com>

diff --git a/drivers/cpu/cpu-uclass.c b/drivers/cpu/cpu-uclass.c
index 457f77b7c89a45f6e4afb24686e895e1e9dcdf1a..8352e2eb0bc5382663a60b633c137d52a6ac1969 100644 (file)
--- a/drivers/cpu/cpu-uclass.c
+++ b/drivers/cpu/cpu-uclass.c
@@ -10,6 +10,7 @@
 #include <errno.h>
 #include <dm/lists.h>
 #include <dm/root.h>
+#include <linux/err.h>
 
 int cpu_probe_all(void)
 {
@@ -34,6 +35,39 @@ int cpu_probe_all(void)
        return 0;
 }
 
+int cpu_is_current(struct udevice *cpu)
+{
+       struct cpu_ops *ops = cpu_get_ops(cpu);
+
+       if (ops->is_current) {
+               if (ops->is_current(cpu))
+                       return 1;
+       }
+
+       return -ENOSYS;
+}
+
+struct udevice *cpu_get_current_dev(void)
+{
+       struct udevice *cpu;
+       int ret;
+
+       uclass_foreach_dev_probe(UCLASS_CPU, cpu) {
+               if (cpu_is_current(cpu) > 0)
+                       return cpu;
+       }
+
+       /* If can't find current cpu device, use the first dev instead */
+       ret = uclass_first_device_err(UCLASS_CPU, &cpu);
+       if (ret) {
+               debug("%s: Could not get CPU device (err = %d)\n",
+                     __func__, ret);
+               return NULL;
+       }
+
+       return cpu;
+}
+
 int cpu_get_desc(struct udevice *dev, char *buf, int size)
 {
        struct cpu_ops *ops = cpu_get_ops(dev);

diff --git a/include/cpu.h b/include/cpu.h
index 6b1b6b37b3bf2446b1f840dc9beb3cd1f117e25a..2f283fe2449dcf620b6b0029ccffa2e4dfdb217f 100644 (file)
--- a/include/cpu.h
+++ b/include/cpu.h
@@ -89,6 +89,15 @@ struct cpu_ops {
         * @return 0 if OK, -ENOSPC if buffer is too small, other -ve on error
         */
        int (*get_vendor)(struct udevice *dev, char *buf, int size);
+
+       /**
+        * is_current() - Check if the CPU that U-Boot is currently running from
+        *
+        * @dev:        Device to check (UCLASS_CPU)
+        * @return 1 if the CPU that U-Boot is currently running from, 0
+        *         if not.
+        */
+       int (*is_current)(struct udevice *dev);
 };
 
 #define cpu_get_ops(dev)        ((struct cpu_ops *)(dev)->driver->ops)
@@ -137,4 +146,18 @@ int cpu_get_vendor(struct udevice *dev, char *buf, int size);
  */
 int cpu_probe_all(void);
 
+/**
+ * cpu_is_current() - Check if the CPU that U-Boot is currently running from
+ *
+ * Return: 1 if yes, - 0 if not
+ */
+int cpu_is_current(struct udevice *cpu);
+
+/**
+ * cpu_get_current_dev() - Get CPU udevice for current CPU
+ *
+ * Return: udevice if OK, - NULL on error
+ */
+struct udevice *cpu_get_current_dev(void);
+
 #endif