On 7/9/20 2:35 AM, Havard Skinnemoen wrote:
> Enough functionality to boot the Linux kernel has been implemented. This
> includes:
>
> - Correct power-on reset values so the various clock rates can be
> accurately calculated.
> - Clock enables stick around when written.
>
> In addition, a best effort attempt to implement SECCNT and CNTR25M was
> made even though I don't think the kernel needs them.
>
> Reviewed-by: Tyrone Ting <[email protected]>
> Reviewed-by: Joel Stanley <[email protected]>
> Reviewed-by: Cédric Le Goater <[email protected]>
> Signed-off-by: Havard Skinnemoen <[email protected]>
> ---
> include/hw/misc/npcm7xx_clk.h | 66 ++++++++++
> hw/misc/npcm7xx_clk.c | 230 ++++++++++++++++++++++++++++++++++
> hw/misc/Makefile.objs | 1 +
> hw/misc/trace-events | 4 +
> 4 files changed, 301 insertions(+)
> create mode 100644 include/hw/misc/npcm7xx_clk.h
> create mode 100644 hw/misc/npcm7xx_clk.c
>
...
> +static uint64_t npcm7xx_clk_read(void *opaque, hwaddr offset, unsigned size)
> +{
> + uint32_t reg = offset / sizeof(uint32_t);
> + NPCM7xxCLKState *s = opaque;
> + int64_t now_ns;
> + uint32_t value = 0;
> +
> + if (reg >= NPCM7XX_CLK_NR_REGS) {
> + qemu_log_mask(LOG_GUEST_ERROR, "%s: offset 0x%04x out of range\n",
> + __func__, (unsigned int)offset);
> + return 0;
> + }
> +
> + switch (reg) {
> + case NPCM7XX_CLK_SWRSTR:
> + qemu_log_mask(LOG_GUEST_ERROR, "%s: register @ 0x%04x is
> write-only\n",
> + __func__, (unsigned int)offset);
> + break;
> +
> + case NPCM7XX_CLK_SECCNT:
> + now_ns = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
> + value = (now_ns - s->ref_ns) / NANOSECONDS_PER_SECOND;
> + break;
> +
> + case NPCM7XX_CLK_CNTR25M:
> + now_ns = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
> + /*
> + * This register counts 25 MHz cycles, updating every 640 ns. It
> rolls
> + * over to zero every second.
> + *
> + * The 4 LSBs are always zero: (1e9 / 640) << 4 = 25000000.
> + */
> + value = (((now_ns - s->ref_ns) / 640) << 4) % 25000000;
Can we declare NPCM7XX_TIMER_REF_HZ in hw/misc/npcm7xx_clk.h and
have the timer device include hw/misc/npcm7xx_clk.h?
> + break;
> +
> + default:
> + value = s->regs[reg];
> + break;
> + };
> +
> + trace_npcm7xx_clk_read(offset, value);
> +
> + return value;
> +}
...
