arm: Add Clock peripheral stub to NRF51 SOC

This stubs enables the microbit-micropython firmware to run
on the microbit machine.

Signed-off-by: Steffen Görtz <contrib@steffen-goertz.de>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190103091119.9367-12-stefanha@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/arm/nrf51_soc.c

@@ -34,6 +34,26 @@
 
 #define BASE_TO_IRQ(base) ((base >> 12) & 0x1F)
 
+static uint64_t clock_read(void *opaque, hwaddr addr, unsigned int size)
+{
+    qemu_log_mask(LOG_UNIMP, "%s: 0x%" HWADDR_PRIx " [%u]\n",
+                  __func__, addr, size);
+    return 1;
+}
+
+static void clock_write(void *opaque, hwaddr addr, uint64_t data,
+                        unsigned int size)
+{
+    qemu_log_mask(LOG_UNIMP, "%s: 0x%" HWADDR_PRIx " <- 0x%" PRIx64 " [%u]\n",
+                  __func__, addr, data, size);
+}
+
+static const MemoryRegionOps clock_ops = {
+    .read = clock_read,
+    .write = clock_write
+};
+
+
 static void nrf51_soc_realize(DeviceState *dev_soc, Error **errp)
 {
     NRF51State *s = NRF51_SOC(dev_soc);
@@ -130,6 +150,12 @@ static void nrf51_soc_realize(DeviceState *dev_soc, Error **errp)
                                             BASE_TO_IRQ(base_addr)));
     }
 
+    /* STUB Peripherals */
+    memory_region_init_io(&s->clock, NULL, &clock_ops, NULL,
+                          "nrf51_soc.clock", 0x1000);
+    memory_region_add_subregion_overlap(&s->container,
+                                        NRF51_IOMEM_BASE, &s->clock, -1);
+
     create_unimplemented_device("nrf51_soc.io", NRF51_IOMEM_BASE,
                                 NRF51_IOMEM_SIZE);
     create_unimplemented_device("nrf51_soc.ficr", NRF51_FICR_BASE,

include/hw/arm/nrf51_soc.h

@@ -38,6 +38,7 @@ typedef struct NRF51State {
     MemoryRegion iomem;
     MemoryRegion sram;
     MemoryRegion flash;
+    MemoryRegion clock;
 
     uint32_t sram_size;
     uint32_t flash_size;