The I2C interrupts are only routed to the legacy interrupt controller. This means
that for modern device trees that use the GIC, the interrupts don't work. This patch
adds a splitter to route the I2C interrupt to both the legacy interrupt controller and the GIC.

Testing

Add these lines to QEMU invocation

-drive if=none,id=i2c_storage,format=raw,file=eeprom.bin \
-device at24c-eeprom,bus=i2c-bus.1,address=0x50,drive=i2c_storage,rom-size=4096 \

note: eeprom.bin is all zeros

Before this change, running i2c get to read from EEPROM would result in this

i2cget -y 1 0x50
Error: Read failed

After this change, running i2c to read from EEPROM results in this

i2cget -y 1 0x50
0x00

The eeprom can now also be enabled in the device tree. Before the
eeprom driver load would fail due to the read failing

ls -l /sys/bus/i2c/devices/i2c-1/1-0050/ | grep -i eeprom
-rw------- 1 root root 4096 May 17 16:57 eeprom

Signed-off-by: Nicholas Righi <nicholasrighi@gmail.com>
---
Changes v1 -> v2:
    - Use a splitter to route the OR gated i2c interrupt to both the
      legacy interrupt controller and the GIC, instead of just replacing
      the legacy routing with the GIC routing
---
 hw/arm/bcm2835_peripherals.c         | 9 +++++++++
 hw/arm/bcm2838.c                     | 4 ++++
 include/hw/arm/bcm2835_peripherals.h | 2 ++
 include/hw/arm/bcm2838_peripherals.h | 1 +
 4 files changed, 16 insertions(+)

diff --git a/hw/arm/bcm2835_peripherals.c b/hw/arm/bcm2835_peripherals.c
index 8a1e72dfab..558c180df9 100644
--- a/hw/arm/bcm2835_peripherals.c
+++ b/hw/arm/bcm2835_peripherals.c
@@ -179,6 +179,8 @@ static void raspi_peripherals_base_init(Object *obj)
                             &s->orgated_i2c_irq, TYPE_OR_IRQ);
     object_property_set_int(OBJECT(&s->orgated_i2c_irq), "num-lines",
                             ORGATED_I2C_IRQ_COUNT, &error_abort);
+    object_initialize_child(obj, "orgated-i2c-irq-splitter",
+                            &s->orgated_i2c_irq_splitter, TYPE_SPLIT_IRQ);
 }
 
 static void bcm2835_peripherals_realize(DeviceState *dev, Error **errp)
@@ -504,7 +506,14 @@ void bcm_soc_peripherals_common_realize(DeviceState *dev, Error **errp)
         sysbus_connect_irq(SYS_BUS_DEVICE(&s->i2c[n]), 0,
                            qdev_get_gpio_in(DEVICE(&s->orgated_i2c_irq), n));
     }
+
+    qdev_prop_set_uint32(DEVICE(&s->orgated_i2c_irq_splitter), "num-lines", 2);
+    if (!qdev_realize(DEVICE(&s->orgated_i2c_irq_splitter), NULL, errp)) {
+        return;
+    }
     qdev_connect_gpio_out(DEVICE(&s->orgated_i2c_irq), 0,
+                          qdev_get_gpio_in(DEVICE(&s->orgated_i2c_irq_splitter), 0));
+    qdev_connect_gpio_out(DEVICE(&s->orgated_i2c_irq_splitter), 0,
                           qdev_get_gpio_in_named(DEVICE(&s->ic),
                                                  BCM2835_IC_GPU_IRQ,
                                                  INTERRUPT_I2C));
diff --git a/hw/arm/bcm2838.c b/hw/arm/bcm2838.c
index c14a854046..089af412a3 100644
--- a/hw/arm/bcm2838.c
+++ b/hw/arm/bcm2838.c
@@ -184,6 +184,10 @@ static void bcm2838_realize(DeviceState *dev, Error **errp)
     sysbus_connect_irq(SYS_BUS_DEVICE(&ps_base->aux), 0,
                        qdev_get_gpio_in(gicdev, GIC_SPI_INTERRUPT_AUX_UART1));
 
+    /* Connect the I2C interrupt to the interrupt controller */
+    qdev_connect_gpio_out(DEVICE(&ps_base->orgated_i2c_irq_splitter), 1,
+                          qdev_get_gpio_in(gicdev, GIC_SPI_INTERRUPT_I2C));
+
     /* Connect VC mailbox to the interrupt controller */
     sysbus_connect_irq(SYS_BUS_DEVICE(&ps_base->mboxes), 0,
                        qdev_get_gpio_in(gicdev, GIC_SPI_INTERRUPT_MBOX));
diff --git a/include/hw/arm/bcm2835_peripherals.h b/include/hw/arm/bcm2835_peripherals.h
index bf35bb18e5..4f356f4643 100644
--- a/include/hw/arm/bcm2835_peripherals.h
+++ b/include/hw/arm/bcm2835_peripherals.h
@@ -33,6 +33,7 @@
 #include "hw/usb/hcd-dwc2.h"
 #include "hw/ssi/bcm2835_spi.h"
 #include "hw/i2c/bcm2835_i2c.h"
+#include "hw/core/split-irq.h"
 #include "hw/nvram/bcm2835_otp.h"
 #include "hw/misc/unimp.h"
 #include "qom/object.h"
@@ -72,6 +73,7 @@ struct BCMSocPeripheralBaseState {
     BCM2835SPIState spi[1];
     BCM2835I2CState i2c[3];
     OrIRQState orgated_i2c_irq;
+    SplitIRQ orgated_i2c_irq_splitter;
     BCM2835OTPState otp;
     UnimplementedDeviceState dbus;
     UnimplementedDeviceState ave0;
diff --git a/include/hw/arm/bcm2838_peripherals.h b/include/hw/arm/bcm2838_peripherals.h
index 7ee1bd066f..0be97e67c7 100644
--- a/include/hw/arm/bcm2838_peripherals.h
+++ b/include/hw/arm/bcm2838_peripherals.h
@@ -22,6 +22,7 @@
 #define GIC_SPI_INTERRUPT_DMA_7_8      87
 #define GIC_SPI_INTERRUPT_DMA_9_10     88
 #define GIC_SPI_INTERRUPT_AUX_UART1    93
+#define GIC_SPI_INTERRUPT_I2C          117
 #define GIC_SPI_INTERRUPT_SDHOST       120
 #define GIC_SPI_INTERRUPT_UART0        121
 #define GIC_SPI_INTERRUPT_RNG200       125
-- 
2.54.0