arm: Remove system_clock_scale global

All the devices that used to use system_clock_scale have now been
converted to use Clock inputs instead, so the global is no longer
needed; remove it and all the code that sets it.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20210812093356.1946-26-peter.maydell@linaro.org

hw/arm/armsse.c

@@ -689,17 +689,6 @@ static void armsse_forward_sec_resp_cfg(ARMSSE *s)
     qdev_connect_gpio_out(dev_splitter, 2, s->sec_resp_cfg_in);
 }
 
-static void armsse_mainclk_update(void *opaque, ClockEvent event)
-{
-    ARMSSE *s = ARM_SSE(opaque);
-
-    /*
-     * Set system_clock_scale from our Clock input; this is what
-     * controls the tick rate of the CPU SysTick timer.
-     */
-    system_clock_scale = clock_ticks_to_ns(s->mainclk, 1);
-}
-
 static void armsse_init(Object *obj)
 {
     ARMSSE *s = ARM_SSE(obj);
@@ -711,8 +700,7 @@ static void armsse_init(Object *obj)
     assert(info->sram_banks <= MAX_SRAM_BANKS);
     assert(info->num_cpus <= SSE_MAX_CPUS);
 
-    s->mainclk = qdev_init_clock_in(DEVICE(s), "MAINCLK",
-                                    armsse_mainclk_update, s, ClockUpdate);
+    s->mainclk = qdev_init_clock_in(DEVICE(s), "MAINCLK", NULL, NULL, 0);
     s->s32kclk = qdev_init_clock_in(DEVICE(s), "S32KCLK", NULL, NULL, 0);
 
     memory_region_init(&s->container, obj, "armsse-container", UINT64_MAX);
@@ -1654,9 +1642,6 @@ static void armsse_realize(DeviceState *dev, Error **errp)
      * devices in the ARMSSE.
      */
     sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->container);
-
-    /* Set initial system_clock_scale from MAINCLK */
-    armsse_mainclk_update(s, ClockUpdate);
 }
 
 static void armsse_idau_check(IDAUInterface *ii, uint32_t address,

hw/arm/mps2.c

@@ -439,8 +439,6 @@ static void mps2_common_init(MachineState *machine)
                  qdev_get_gpio_in(armv7m,
                                   mmc->fpga_type == FPGA_AN511 ? 47 : 13));
 
-    system_clock_scale = NANOSECONDS_PER_SECOND / SYSCLK_FRQ;
-
     armv7m_load_kernel(ARM_CPU(first_cpu), machine->kernel_filename,
                        0x400000);
 }

hw/arm/msf2-soc.c

@@ -144,8 +144,6 @@ static void m2sxxx_soc_realize(DeviceState *dev_soc, Error **errp)
         return;
     }
 
-    system_clock_scale = clock_ticks_to_ns(s->m3clk, 1);
-
     for (i = 0; i < MSF2_NUM_UARTS; i++) {
         if (serial_hd(i)) {
             serial_mm_init(get_system_memory(), uart_addr[i], 2,

hw/arm/netduino2.c

@@ -39,8 +39,6 @@ static void netduino2_init(MachineState *machine)
     DeviceState *dev;
     Clock *sysclk;
 
-    system_clock_scale = NANOSECONDS_PER_SECOND / SYSCLK_FRQ;
-
     /* This clock doesn't need migration because it is fixed-frequency */
     sysclk = clock_new(OBJECT(machine), "SYSCLK");
     clock_set_hz(sysclk, SYSCLK_FRQ);

hw/arm/netduinoplus2.c

@@ -39,8 +39,6 @@ static void netduinoplus2_init(MachineState *machine)
     DeviceState *dev;
     Clock *sysclk;
 
-    system_clock_scale = NANOSECONDS_PER_SECOND / SYSCLK_FRQ;
-
     /* This clock doesn't need migration because it is fixed-frequency */
     sysclk = clock_new(OBJECT(machine), "SYSCLK");
     clock_set_hz(sysclk, SYSCLK_FRQ);

hw/arm/nrf51_soc.c

@@ -84,8 +84,6 @@ static void nrf51_soc_realize(DeviceState *dev_soc, Error **errp)
      * will always provide one).
      */
 
-    system_clock_scale = NANOSECONDS_PER_SECOND / HCLK_FRQ;
-
     object_property_set_link(OBJECT(&s->cpu), "memory", OBJECT(&s->container),
                              &error_abort);
     if (!sysbus_realize(SYS_BUS_DEVICE(&s->cpu), errp)) {

hw/arm/stellaris.c

@@ -263,17 +263,18 @@ static bool ssys_use_rcc2(ssys_state *s)
  */
 static void ssys_calculate_system_clock(ssys_state *s, bool propagate_clock)
 {
+    int period_ns;
     /*
      * SYSDIV field specifies divisor: 0 == /1, 1 == /2, etc.  Input
      * clock is 200MHz, which is a period of 5 ns. Dividing the clock
      * frequency by X is the same as multiplying the period by X.
      */
     if (ssys_use_rcc2(s)) {
-        system_clock_scale = 5 * (((s->rcc2 >> 23) & 0x3f) + 1);
+        period_ns = 5 * (((s->rcc2 >> 23) & 0x3f) + 1);
     } else {
-        system_clock_scale = 5 * (((s->rcc >> 23) & 0xf) + 1);
+        period_ns = 5 * (((s->rcc >> 23) & 0xf) + 1);
     }
-    clock_set_ns(s->sysclk, system_clock_scale);
+    clock_set_ns(s->sysclk, period_ns);
     if (propagate_clock) {
         clock_propagate(s->sysclk);
     }

hw/arm/stm32vldiscovery.c

@@ -42,8 +42,6 @@ static void stm32vldiscovery_init(MachineState *machine)
     DeviceState *dev;
     Clock *sysclk;
 
-    system_clock_scale = NANOSECONDS_PER_SECOND / SYSCLK_FRQ;
-
     /* This clock doesn't need migration because it is fixed-frequency */
     sysclk = clock_new(OBJECT(machine), "SYSCLK");
     clock_set_hz(sysclk, SYSCLK_FRQ);

hw/timer/armv7m_systick.c

@@ -30,8 +30,6 @@
 #define SYSCALIB_SKEW (1U << 30)
 #define SYSCALIB_TENMS ((1U << 24) - 1)
 
-int system_clock_scale;
-
 static void systick_set_period_from_clock(SysTickState *s)
 {
     /*

include/hw/timer/armv7m_systick.h

@@ -47,26 +47,4 @@ struct SysTickState {
     Clock *cpuclk;
 };
 
-/*
- * Multiplication factor to convert from system clock ticks to qemu timer
- * ticks. This should be set (by board code, usually) to a value
- * equal to NANOSECONDS_PER_SECOND / frq, where frq is the clock frequency
- * in Hz of the CPU.
- *
- * This value is used by the systick device when it is running in
- * its "use the CPU clock" mode (ie when SYST_CSR.CLKSOURCE == 1) to
- * set how fast the timer should tick.
- *
- * TODO: we should refactor this so that rather than using a global
- * we use a device property or something similar. This is complicated
- * because (a) the property would need to be plumbed through from the
- * board code down through various layers to the systick device
- * and (b) the property needs to be modifiable after realize, because
- * the stellaris board uses this to implement the behaviour where the
- * guest can reprogram the PLL registers to downclock the CPU, and the
- * systick device needs to react accordingly. Possibly this should
- * be deferred until we have a good API for modelling clock trees.
- */
-extern int system_clock_scale;
-
 #endif