From: Jamin Lin <jamin_...@aspeedtech.com> According to the datasheet: BIT[1] (SCU_FREQ_OSC_EN) enables the oscillator frequency measurement counter. BIT[6] (SCU_FREQ_DONE) indicates the measurement is finished. Firmware polls BIT[6] to determine when measurement is complete. The flag can be cleared by writing BIT[1] to 0.
To simulate this hardware behavior in QEMU: If BIT[1] is set to 1, BIT[6] is immediately set to 1 to avoid firmware hanging during polling. If BIT[1] is cleared to 0, BIT[6] is also cleared to 0 to match hardware semantics. The initial value of this register is initialized to 0x80, reflecting the default value confirmed from an EVB register dump. Signed-off-by: Jamin Lin <jamin_...@aspeedtech.com> Reviewed-by: Cédric Le Goater <c...@redhat.com> Link: https://lore.kernel.org/qemu-devel/20250618080006.846355-3-jamin_...@aspeedtech.com Signed-off-by: Cédric Le Goater <c...@redhat.com> --- hw/misc/aspeed_scu.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/hw/misc/aspeed_scu.c b/hw/misc/aspeed_scu.c index 4930e00fed14..11d073910882 100644 --- a/hw/misc/aspeed_scu.c +++ b/hw/misc/aspeed_scu.c @@ -176,6 +176,7 @@ #define AST2700_SCUIO_UARTCLK_GEN TO_REG(0x330) #define AST2700_SCUIO_HUARTCLK_GEN TO_REG(0x334) #define AST2700_SCUIO_CLK_DUTY_MEAS_RST TO_REG(0x388) +#define AST2700_SCUIO_FREQ_CNT_CTL TO_REG(0x3A0) #define SCU_IO_REGION_SIZE 0x1000 @@ -1022,6 +1023,10 @@ static void aspeed_ast2700_scuio_write(void *opaque, hwaddr offset, s->regs[reg - 1] ^= data; updated = true; break; + case AST2700_SCUIO_FREQ_CNT_CTL: + s->regs[reg] = deposit32(s->regs[reg], 6, 1, !!(data & BIT(1))); + updated = true; + break; default: qemu_log_mask(LOG_GUEST_ERROR, "%s: Unhandled write at offset 0x%" HWADDR_PRIx "\n", @@ -1066,6 +1071,7 @@ static const uint32_t ast2700_a0_resets_io[ASPEED_AST2700_SCU_NR_REGS] = { [AST2700_SCUIO_UARTCLK_GEN] = 0x00014506, [AST2700_SCUIO_HUARTCLK_GEN] = 0x000145c0, [AST2700_SCUIO_CLK_DUTY_MEAS_RST] = 0x0c9100d2, + [AST2700_SCUIO_FREQ_CNT_CTL] = 0x00000080, }; static void aspeed_2700_scuio_class_init(ObjectClass *klass, const void *data) -- 2.50.0
