zynqmp: pm: Add SiP call to obtain PM callback data

The callback IRQ is delivered to the NS OS. Provide an interface to
allow the NS OS to obtain the callback data from the secure HW.
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>

plat/xilinx/zynqmp/pm_service/pm_api_sys.c

@@ -557,3 +557,16 @@ enum pm_ret_status pm_get_chipid(uint32_t *value)
 	PM_PACK_PAYLOAD1(payload, PM_GET_CHIPID);
 	return pm_ipi_send_sync(primary_proc, payload, value, 2);
 }
+
+/**
+ * pm_get_callbackdata() - Read from IPI response buffer
+ * @data - array of PAYLOAD_ARG_CNT elements
+ *
+ * Read value from ipi buffer response buffer.
+ */
+void pm_get_callbackdata(uint32_t *data, size_t count)
+{
+
+	pm_ipi_buff_read_callb(data, count);
+	pm_ipi_irq_clear();
+}

plat/xilinx/zynqmp/pm_service/pm_api_sys.h

@@ -116,5 +116,6 @@ enum pm_ret_status pm_fpga_load(uint32_t address_high,
 enum pm_ret_status pm_fpga_get_status(unsigned int *value);
 
 enum pm_ret_status pm_get_chipid(uint32_t *value);
+void pm_get_callbackdata(uint32_t *data, size_t count);
 
 #endif /* _PM_API_SYS_H_ */

plat/xilinx/zynqmp/pm_service/pm_ipi.c

@@ -56,6 +56,8 @@
 #define IPI_BUFFER_TARGET_PL_3_OFFSET	0x180U
 #define IPI_BUFFER_TARGET_PMU_OFFSET	0x1C0U
 
+#define IPI_BUFFER_MAX_WORDS	8
+
 #define IPI_BUFFER_REQ_OFFSET	0x0U
 #define IPI_BUFFER_RESP_OFFSET	0x20U
 
@@ -217,6 +219,29 @@ static enum pm_ret_status pm_ipi_buff_read(const struct pm_proc *proc,
 	return mmio_read_32(buffer_base);
 }
 
+/**
+ * pm_ipi_buff_read_callb() - Reads IPI response after PMU has handled interrupt
+ * @value	Used to return value from IPI buffer element (optional)
+ * @count	Number of values to return in @value
+ *
+ * @return	Returns status, either success or error+reason
+ */
+void pm_ipi_buff_read_callb(unsigned int *value, size_t count)
+{
+	size_t i;
+	uintptr_t buffer_base = IPI_BUFFER_PMU_BASE +
+				IPI_BUFFER_TARGET_APU_OFFSET +
+				IPI_BUFFER_REQ_OFFSET;
+
+	if (count > IPI_BUFFER_MAX_WORDS)
+		count = IPI_BUFFER_MAX_WORDS;
+
+	for (i = 0; i <= count; i++) {
+		*value = mmio_read_32(buffer_base + (i * PAYLOAD_ARG_SIZE));
+		value++;
+	}
+}
+
 /**
  * pm_ipi_send_sync() - Sends IPI request to the PMU
  * @proc	Pointer to the processor who is initiating request
@@ -258,3 +283,8 @@ void pm_ipi_irq_disable(void)
 {
 	mmio_write_32(IPI_APU_IDR, IPI_APU_IXR_PMU_0_MASK);
 }
+
+void pm_ipi_irq_clear(void)
+{
+	mmio_write_32(IPI_APU_ISR, IPI_APU_IXR_PMU_0_MASK);
+}

plat/xilinx/zynqmp/pm_service/pm_ipi.h

@@ -40,7 +40,9 @@ enum pm_ret_status pm_ipi_send(const struct pm_proc *proc,
 enum pm_ret_status pm_ipi_send_sync(const struct pm_proc *proc,
 				    uint32_t payload[PAYLOAD_ARG_CNT],
 				    unsigned int *value, size_t count);
+void pm_ipi_buff_read_callb(unsigned int *value, size_t count);
 void pm_ipi_irq_enable(void);
 void pm_ipi_irq_disable(void);
+void pm_ipi_irq_clear(void);
 
 #endif /* _PM_IPI_H_ */

plat/xilinx/zynqmp/pm_service/pm_svc_main.c

@@ -42,6 +42,8 @@
 #include "pm_ipi.h"
 #include "../zynqmp_private.h"
 
+#define PM_GET_CALLBACK_DATA	0xa01
+
 /* 0 - UP, !0 - DOWN */
 static int32_t pm_down = !0;
 
@@ -257,6 +259,16 @@ uint64_t pm_smc_handler(uint32_t smc_fid, uint64_t x1, uint64_t x2, uint64_t x3,
 			 result[1]);
 	}
 
+	case PM_GET_CALLBACK_DATA:
+	{
+		uint32_t result[4];
+
+		pm_get_callbackdata(result, sizeof(result));
+		SMC_RET2(handle,
+			 (uint64_t)result[0] | ((uint64_t)result[1] << 32),
+			 (uint64_t)result[2] | ((uint64_t)result[3] << 32));
+	}
+
 	default:
 		WARN("Unimplemented PM Service Call: 0x%x\n", smc_fid);
 		SMC_RET1(handle, SMC_UNK);