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hw/ppc/e500: fix bus-frequency property hardcoded to zero in CPU FDT node

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The bus-frequency property in the CPU FDT node was hardcoded to 0.
This is incorrect - it should reflect the actual platform bus clock
frequency, as firmware and RTOSes use it to derive peripheral clock
rates.

Notably, the RTEMS QorIQ BSP uses bus-frequency to program the MPIC
global timer interval. With bus-frequency=0, the timer interval
overflows to ~85 seconds, preventing any clock interrupts from firing.

Fix by adding a bus_freq field to PPCE500MachineClass and using it in
the FDT generator. Set bus_freq = PLATFORM_CLK_FREQ_HZ (400MHz) for
existing machines, matching the existing clock_freq value.

Signed-off-by: Vivien LEGER <vivien.leger@gmail.com>
Reviewed-by: Bernhard Beschow <shentey@gmail.com>
Message-ID: <20260411154535.1451361-1-vivien.leger@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
This commit is contained in:
Vivien LEGER
2026-04-11 17:45:35 +02:00
committed by Philippe Mathieu-Daudé
parent 12ce4d9630
commit 774e6f5c15
4 changed files with 4 additions and 1 deletions
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2
hw/ppc/e500.c
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@@ -518,7 +518,7 @@ static int ppce500_load_device_tree(PPCE500MachineState *pms,
env->icache_line_size);
qemu_fdt_setprop_cell(fdt, cpu_name, "d-cache-size", 0x8000);
qemu_fdt_setprop_cell(fdt, cpu_name, "i-cache-size", 0x8000);
qemu_fdt_setprop_cell(fdt, cpu_name, "bus-frequency", 0);
qemu_fdt_setprop_cell(fdt, cpu_name, "bus-frequency", pmc->bus_freq);
if (cpu->cpu_index) {
qemu_fdt_setprop_string(fdt, cpu_name, "status", "disabled");
qemu_fdt_setprop_string(fdt, cpu_name, "enable-method",

1
hw/ppc/e500.h
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@@ -40,6 +40,7 @@ struct PPCE500MachineClass {
hwaddr pci_mmio_bus_base;
hwaddr spin_base;
uint32_t clock_freq;
uint32_t bus_freq;
uint32_t tb_freq;
};

1
hw/ppc/e500plat.c
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@@ -94,6 +94,7 @@ static void e500plat_machine_class_init(ObjectClass *oc, const void *data)
pmc->pci_mmio_bus_base = 0xE0000000ULL;
pmc->spin_base = 0xFEF000000ULL;
pmc->clock_freq = PLATFORM_CLK_FREQ_HZ;
pmc->bus_freq = PLATFORM_CLK_FREQ_HZ;
pmc->tb_freq = PLATFORM_CLK_FREQ_HZ;
mc->desc = "generic paravirt e500 platform";

1
hw/ppc/mpc8544ds.c
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@@ -56,6 +56,7 @@ static void mpc8544ds_machine_class_init(ObjectClass *oc, const void *data)
pmc->pci_pio_base = 0xE1000000ULL;
pmc->spin_base = 0xEF000000ULL;
pmc->clock_freq = PLATFORM_CLK_FREQ_HZ;
pmc->bus_freq = PLATFORM_CLK_FREQ_HZ;
pmc->tb_freq = PLATFORM_CLK_FREQ_HZ;
mc->desc = "mpc8544ds";