Add P9 DIO interrupt support

On P9 there are GPIO port 0, 1, 2 for GPIO interrupt, and DIO interrupt
is used to handle the interrupts.

Add support to the DIO interrupts:
1. Add dio_interrupt_register(chip, port, callback) to register the
   interrupt;
2. Add dio_interrupt_deregister(chip, port, callback) to deregister;
3. When interrupt on the port occurs, callback is invoked, and the
   interrupt status is cleared.

Signed-off-by: Lei YU <mine260309@gmail.com>
[oliver: Fixed Makefile.inc merge conflict]
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Stewart Smith <stewart@linux.ibm.com>

3 files changed, 149 insertions, 1 deletions

diff --git a/hw/Makefile.inc b/hw/Makefile.inc
index fbafd82..2885b50 100644
--- a/hw/Makefile.inc
+++ b/hw/Makefile.inc
@@ -9,7 +9,7 @@ HW_OBJS += dts.o lpc-rtc.o npu.o npu-hw-procedures.o xive.o phb4.o
 HW_OBJS += fake-nvram.o lpc-mbox.o npu2.o npu2-hw-procedures.o
 HW_OBJS += npu2-common.o phys-map.o sbe-p9.o capp.o occ-sensor.o vas.o
 HW_OBJS += npu2-opencapi.o phys-map.o sbe-p9.o capp.o occ-sensor.o
-HW_OBJS += vas.o sbe-p8.o
+HW_OBJS += vas.o sbe-p8.o dio-p9.o
 HW_OBJS += lpc-port80h.o
 HW=hw/built-in.a
 
diff --git a/hw/dio-p9.c b/hw/dio-p9.c
new file mode 100644
index 0000000..e2d40ac
--- /dev/null
+++ b/hw/dio-p9.c
@@ -0,0 +1,146 @@
+/* Copyright 2019 IBM Corp.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *	http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+ * implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+#define pr_fmt(fmt) "DIO: " fmt
+
+#include <chip.h>
+#include <dio-p9.h>
+#include <opal.h>
+#include <xscom.h>
+#include <xscom-p9-regs.h>
+
+void p9_dio_init(void)
+{
+	struct dt_node *xn;
+	struct proc_chip *chip;
+	struct p9_dio *dio;
+
+	if (proc_gen < proc_gen_p9)
+		return;
+
+	dt_for_each_compatible(dt_root, xn, "ibm,xscom") {
+		dio = zalloc(sizeof(struct p9_dio));
+		assert(dio);
+		chip = get_chip(dt_get_chip_id(xn));
+		assert(chip);
+		chip->dio = dio;
+	}
+}
+
+int dio_interrupt_register(struct proc_chip *chip,
+		int port, dio_interrupt_callback callback)
+{
+	u64 val;
+	int rc;
+
+	assert(chip);
+	assert(chip->dio);
+
+	if (port < 0 || port >= NUM_OF_P9_DIO_PORTS)
+		return OPAL_PARAMETER;
+
+	if (chip->dio->callbacks[port]) /* This port already has a callback */
+		return OPAL_PARAMETER;
+
+	rc = xscom_read(chip->id, P9_GPIO_INTERRUPT_ENABLE, &val);
+	if (rc != OPAL_SUCCESS) {
+		prlog(PR_ERR, "XSCOM error %d reading reg 0x%llx\n",
+				rc, P9_GPIO_INTERRUPT_ENABLE);
+		return OPAL_HARDWARE;
+	}
+
+	val |= PPC_BIT(port);
+	rc = xscom_write(chip->id, P9_GPIO_INTERRUPT_ENABLE, val);
+	if (rc != OPAL_SUCCESS) {
+		prlog(PR_ERR, "XSCOM error %d writing reg 0x%llx\n",
+				rc, P9_GPIO_INTERRUPT_ENABLE);
+		return OPAL_HARDWARE;
+	}
+
+	chip->dio->callbacks[port] = callback;
+
+	return OPAL_SUCCESS;
+}
+
+int dio_interrupt_deregister(struct proc_chip* chip,
+		int port, dio_interrupt_callback callback)
+{
+	u64 val;
+	int rc;
+
+	assert(chip);
+	assert(chip->dio);
+
+	if (port < 0 || port >= NUM_OF_P9_DIO_PORTS)
+		return OPAL_PARAMETER;
+
+	if (chip->dio->callbacks[port] != callback)
+		return OPAL_PARAMETER;
+
+	rc = xscom_read(chip->id, P9_GPIO_INTERRUPT_ENABLE, &val);
+	if (rc != OPAL_SUCCESS) {
+		prlog(PR_ERR, "XSCOM error %d reading reg 0x%llx\n",
+				rc, P9_GPIO_INTERRUPT_ENABLE);
+		return OPAL_HARDWARE;
+	}
+
+	val &= ~PPC_BIT(port);
+	rc = xscom_write(chip->id, P9_GPIO_INTERRUPT_ENABLE, val);
+	if (rc != OPAL_SUCCESS) {
+		prlog(PR_ERR, "XSCOM error %d writing reg 0x%llx\n",
+				rc, P9_GPIO_INTERRUPT_ENABLE);
+		return OPAL_HARDWARE;
+	}
+
+	chip->dio->callbacks[port] = NULL;
+
+	return OPAL_SUCCESS;
+}
+
+void dio_interrupt_handler(uint32_t chip_id)
+{
+	struct proc_chip *chip;
+	u64 val;
+	int rc;
+	int i;
+
+	chip = get_chip(chip_id);
+	if (chip == NULL || chip->dio == NULL)
+		return;
+
+	rc = xscom_read(chip->id, P9_GPIO_INTERRUPT_STATUS, &val);
+	if (rc != OPAL_SUCCESS) {
+		prlog(PR_ERR, "XSCOM error %d reading reg 0x%llx\n",
+				rc, P9_GPIO_INTERRUPT_STATUS);
+		return;
+	}
+
+	for (i = 0; i < NUM_OF_P9_DIO_PORTS; ++i) {
+		if (val & PPC_BIT(i)) {
+			if (chip->dio->callbacks[i])
+				chip->dio->callbacks[i](chip);
+			else
+				prlog(PR_ERR,
+					"DIO interrupt triggerd on chip 0x%x"
+					" port %d but no handler\n",
+					chip->id, i);
+			/* Write 1 to clear the interrupt status */
+			xscom_write(chip->id, P9_GPIO_INTERRUPT_CONDITION,
+					val & PPC_BIT(i));
+		}
+	}
+}
diff --git a/hw/psi.c b/hw/psi.c
index 2f7ab5f..ff6b0a9 100644
--- a/hw/psi.c
+++ b/hw/psi.c
@@ -24,6 +24,7 @@
 #include <gx.h>
 #include <interrupts.h>
 #include <cpu.h>
+#include <dio-p9.h>
 #include <trace.h>
 #include <xscom.h>
 #include <chip.h>
@@ -604,6 +605,7 @@ static void psihb_p9_interrupt(struct irq_source *is, uint32_t isn)
 		break;
 	case P9_PSI_IRQ_DIO:
 		printf("PSI: DIO irq received\n");
+		dio_interrupt_handler(psi->chip_id);
 		break;
 	case P9_PSI_IRQ_PSU:
 		p9_sbe_interrupt(psi->chip_id);