@samitouri / QOSamiQemu / commits / 774e6f5c15

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

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>

Vivien LEGER committed Apr 11, 2026 at 17:45 UTC 774e6f5c1533aba9e04f95cb8cfba64d8329fcb0

4 files changed +4 -1

hw/ppc/e500.c

+1 -1

@@ -518,7 +518,7 @@ static int ppce500_load_device_tree(PPCE500MachineState *pms,

518 env->icache_line_size);

519 qemu_fdt_setprop_cell(fdt, cpu_name, "d-cache-size", 0x8000);

520 qemu_fdt_setprop_cell(fdt, cpu_name, "i-cache-size", 0x8000);

521 - qemu_fdt_setprop_cell(fdt, cpu_name, "bus-frequency", 0);

521 + qemu_fdt_setprop_cell(fdt, cpu_name, "bus-frequency", pmc->bus_freq);

522 if (cpu->cpu_index) {

523 qemu_fdt_setprop_string(fdt, cpu_name, "status", "disabled");

524 qemu_fdt_setprop_string(fdt, cpu_name, "enable-method",

hw/ppc/e500.h

@@ -40,6 +40,7 @@ struct PPCE500MachineClass {

40 hwaddr pci_mmio_bus_base;

41 hwaddr spin_base;

42 uint32_t clock_freq;

43 + uint32_t bus_freq;

44 uint32_t tb_freq;

45 };

hw/ppc/e500plat.c

@@ -94,6 +94,7 @@ static void e500plat_machine_class_init(ObjectClass *oc, const void *data)

94 pmc->pci_mmio_bus_base = 0xE0000000ULL;

95 pmc->spin_base = 0xFEF000000ULL;

96 pmc->clock_freq = PLATFORM_CLK_FREQ_HZ;

97 + pmc->bus_freq = PLATFORM_CLK_FREQ_HZ;

98 pmc->tb_freq = PLATFORM_CLK_FREQ_HZ;

100 mc->desc = "generic paravirt e500 platform";

hw/ppc/mpc8544ds.c

@@ -56,6 +56,7 @@ static void mpc8544ds_machine_class_init(ObjectClass *oc, const void *data)

56 pmc->pci_pio_base = 0xE1000000ULL;

57 pmc->spin_base = 0xEF000000ULL;

58 pmc->clock_freq = PLATFORM_CLK_FREQ_HZ;

59 + pmc->bus_freq = PLATFORM_CLK_FREQ_HZ;

60 pmc->tb_freq = PLATFORM_CLK_FREQ_HZ;

62 mc->desc = "mpc8544ds";