[PATCH v3 1/3] firmware: imx: introduce imx_sc_pm_get_resource_power_mode()

[Hiago De Franco <hiagofranco@gmail.com>]

From: Hiago De Franco <hiago.franco@toradex.com>

This SCU API returns the power mode of a given resource.

As example, remoteproc/imx_rproc.c can now use this function to check
the power mode of the remote core to properly set "attached" or
"offline" modes.

Since there is no proper firmware/imx file to place this function, also
introduce firmware/imx/power.c file to keep all the PM functions inside.

Signed-off-by: Hiago De Franco <hiago.franco@toradex.com>
Suggested-by: Peng Fan <peng.fan@nxp.com>
---
v3: New patch.
---
 drivers/firmware/imx/Makefile       |  2 +-
 drivers/firmware/imx/power.c        | 52 +++++++++++++++++++++++++++++
 include/linux/firmware/imx/svc/pm.h |  9 +++++
 3 files changed, 62 insertions(+), 1 deletion(-)
 create mode 100644 drivers/firmware/imx/power.c

diff --git a/drivers/firmware/imx/Makefile b/drivers/firmware/imx/Makefile
index 8d046c341be8..5f5548e34459 100644
--- a/drivers/firmware/imx/Makefile
+++ b/drivers/firmware/imx/Makefile
@@ -1,4 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_IMX_DSP)		+= imx-dsp.o
-obj-$(CONFIG_IMX_SCU)		+= imx-scu.o misc.o imx-scu-irq.o rm.o imx-scu-soc.o
+obj-$(CONFIG_IMX_SCU)		+= imx-scu.o misc.o imx-scu-irq.o rm.o imx-scu-soc.o power.o
 obj-${CONFIG_IMX_SCMI_MISC_DRV}	+= sm-misc.o
diff --git a/drivers/firmware/imx/power.c b/drivers/firmware/imx/power.c
new file mode 100644
index 000000000000..b982cebba72a
--- /dev/null
+++ b/drivers/firmware/imx/power.c
@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * File containing client-side RPC functions for the PM (Power Management)
+ * service. These function are ported to clients that communicate to the SC.
+ */
+
+#include <linux/firmware/imx/svc/pm.h>
+
+struct imx_sc_msg_req_get_resource_power_mode {
+	struct imx_sc_rpc_msg hdr;
+	union {
+		struct {
+			u16 resource;
+		} req;
+		struct {
+			u8 mode;
+		} resp;
+	} data;
+} __packed __aligned(4);
+
+/**
+ * imx_sc_pm_get_resource_power_mode - Get power mode from a given resource.
+ * @ipc: IPC handle.
+ * @resource: Resource to check the power mode.
+ *
+ * Return: Returns < 0 for errors or the following for success:
+ * * %IMX_SC_PM_PW_MODE_OFF	- Power off
+ * * %IMX_SC_PM_PW_MODE_STBY	- Power in standby
+ * * %IMX_SC_PM_PW_MODE_LP	- Power in low-power
+ * * %IMX_SC_PM_PW_MODE_ON	- Power on
+ *
+ */
+int imx_sc_pm_get_resource_power_mode(struct imx_sc_ipc *ipc, u32 resource)
+{
+	struct imx_sc_msg_req_get_resource_power_mode msg;
+	struct imx_sc_rpc_msg *hdr = &msg.hdr;
+	int ret;
+
+	hdr->ver = IMX_SC_RPC_VERSION;
+	hdr->svc = IMX_SC_RPC_SVC_PM;
+	hdr->func = IMX_SC_PM_FUNC_GET_RESOURCE_POWER_MODE;
+	hdr->size = 2;
+
+	msg.data.req.resource = resource;
+
+	ret = imx_scu_call_rpc(ipc, &msg, true);
+	if (ret)
+		return ret;
+
+	return msg.data.resp.mode;
+}
+EXPORT_SYMBOL(imx_sc_pm_get_resource_power_mode);
diff --git a/include/linux/firmware/imx/svc/pm.h b/include/linux/firmware/imx/svc/pm.h
index 1f6975dd37b0..56e93a953295 100644
--- a/include/linux/firmware/imx/svc/pm.h
+++ b/include/linux/firmware/imx/svc/pm.h
@@ -82,4 +82,13 @@ enum imx_sc_pm_func {
 #define IMX_SC_PM_PARENT_PLL2	3	/* Parent in PLL2 or PLL0/4 */
 #define IMX_SC_PM_PARENT_BYPS	4	/* Parent is a bypass clock. */
 
+#if IS_ENABLED(CONFIG_IMX_SCU)
+int imx_sc_pm_get_resource_power_mode(struct imx_sc_ipc *ipc, u32 resource);
+#else
+static inline int imx_sc_pm_get_resource_power_mode(struct imx_sc_ipc *ipc,
+						    u32 resource)
+{
+	return -EOPNOTSUPP;
+}
+#endif
 #endif /* _SC_PM_API_H */
-- 
2.39.5