hw/arm/stm32l4x5_soc.c: Use the RCC Sysclk

Now that we can generate reliable clock frequencies from the RCC, remove
the hacky definition of the sysclk in the b_l475e_iot01a initialisation
code and use the correct RCC clock.

Signed-off-by: Arnaud Minier <arnaud.minier@telecom-paris.fr>
Signed-off-by: Inès Varhol <ines.varhol@telecom-paris.fr>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20240303140643.81957-8-arnaud.minier@telecom-paris.fr
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/arm/b-l475e-iot01a.c

@@ -26,27 +26,19 @@
 #include "qapi/error.h"
 #include "hw/boards.h"
 #include "hw/qdev-properties.h"
-#include "hw/qdev-clock.h"
 #include "qemu/error-report.h"
 #include "hw/arm/stm32l4x5_soc.h"
 #include "hw/arm/boot.h"
 
-/* Main SYSCLK frequency in Hz (80MHz) */
-#define MAIN_SYSCLK_FREQ_HZ 80000000ULL
+/* B-L475E-IOT01A implementation is derived from netduinoplus2 */
 
 static void b_l475e_iot01a_init(MachineState *machine)
 {
     const Stm32l4x5SocClass *sc;
     DeviceState *dev;
-    Clock *sysclk;
-
-    /* This clock doesn't need migration because it is fixed-frequency */
-    sysclk = clock_new(OBJECT(machine), "SYSCLK");
-    clock_set_hz(sysclk, MAIN_SYSCLK_FREQ_HZ);
 
     dev = qdev_new(TYPE_STM32L4X5XG_SOC);
     object_property_add_child(OBJECT(machine), "soc", OBJECT(dev));
-    qdev_connect_clock_in(dev, "sysclk", sysclk);
     sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
 
     sc = STM32L4X5_SOC_GET_CLASS(dev);

hw/arm/stm32l4x5_soc.c

@@ -110,9 +110,6 @@ static void stm32l4x5_soc_initfn(Object *obj)
     }
     object_initialize_child(obj, "syscfg", &s->syscfg, TYPE_STM32L4X5_SYSCFG);
     object_initialize_child(obj, "rcc", &s->rcc, TYPE_STM32L4X5_RCC);
-
-    s->sysclk = qdev_init_clock_in(DEVICE(s), "sysclk", NULL, NULL, 0);
-    s->refclk = qdev_init_clock_in(DEVICE(s), "refclk", NULL, NULL, 0);
 }
 
 static void stm32l4x5_soc_realize(DeviceState *dev_soc, Error **errp)
@@ -124,30 +121,6 @@ static void stm32l4x5_soc_realize(DeviceState *dev_soc, Error **errp)
     DeviceState *armv7m;
     SysBusDevice *busdev;
 
-    /*
-     * We use s->refclk internally and only define it with qdev_init_clock_in()
-     * so it is correctly parented and not leaked on an init/deinit; it is not
-     * intended as an externally exposed clock.
-     */
-    if (clock_has_source(s->refclk)) {
-        error_setg(errp, "refclk clock must not be wired up by the board code");
-        return;
-    }
-
-    if (!clock_has_source(s->sysclk)) {
-        error_setg(errp, "sysclk clock must be wired up by the board code");
-        return;
-    }
-
-    /*
-     * TODO: ideally we should model the SoC RCC and its ability to
-     * change the sysclk frequency and define different sysclk sources.
-     */
-
-    /* The refclk always runs at frequency HCLK / 8 */
-    clock_set_mul_div(s->refclk, 8, 1);
-    clock_set_source(s->refclk, s->sysclk);
-
     if (!memory_region_init_rom(&s->flash, OBJECT(dev_soc), "flash",
                                 sc->flash_size, errp)) {
         return;
@@ -177,8 +150,10 @@ static void stm32l4x5_soc_realize(DeviceState *dev_soc, Error **errp)
     qdev_prop_set_uint32(armv7m, "num-prio-bits", 4);
     qdev_prop_set_string(armv7m, "cpu-type", ARM_CPU_TYPE_NAME("cortex-m4"));
     qdev_prop_set_bit(armv7m, "enable-bitband", true);
-    qdev_connect_clock_in(armv7m, "cpuclk", s->sysclk);
-    qdev_connect_clock_in(armv7m, "refclk", s->refclk);
+    qdev_connect_clock_in(armv7m, "cpuclk",
+        qdev_get_clock_out(DEVICE(&(s->rcc)), "cortex-fclk-out"));
+    qdev_connect_clock_in(armv7m, "refclk",
+        qdev_get_clock_out(DEVICE(&(s->rcc)), "cortex-refclk-out"));
     object_property_set_link(OBJECT(&s->armv7m), "memory",
                              OBJECT(system_memory), &error_abort);
     if (!sysbus_realize(SYS_BUS_DEVICE(&s->armv7m), errp)) {

include/hw/arm/stm32l4x5_soc.h

@@ -54,9 +54,6 @@ struct Stm32l4x5SocState {
     MemoryRegion sram2;
     MemoryRegion flash;
     MemoryRegion flash_alias;
-
-    Clock *sysclk;
-    Clock *refclk;
 };
 
 struct Stm32l4x5SocClass {