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SubjectRe: [PATCH v12 7/8] clocksource/drivers/arm_arch_timer: Add GTDT support for memory-mapped timer
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Hi Marc,


On 09/13/2016 07:00 PM, Marc Zyngier wrote:
> Argh, new version...
>
> On 13/09/16 11:39, fu.wei@linaro.org wrote:
>> From: Fu Wei <fu.wei@linaro.org>
>>
>> The patch add memory-mapped timer register support by using the information
>> provided by the new GTDT driver of ACPI.
>>
>> Signed-off-by: Fu Wei <fu.wei@linaro.org>
>> ---
>> drivers/clocksource/arm_arch_timer.c | 127 ++++++++++++++++++++++++++++++++++-
>> 1 file changed, 124 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
>> index 0197ef9..d33802b 100644
>> --- a/drivers/clocksource/arm_arch_timer.c
>> +++ b/drivers/clocksource/arm_arch_timer.c
>> @@ -888,7 +888,128 @@ CLOCKSOURCE_OF_DECLARE(armv7_arch_timer_mem, "arm,armv7-timer-mem",
>> arch_timer_mem_init);
>>
>> #ifdef CONFIG_ACPI_GTDT
>> -/* Initialize per-processor generic timer */
>> +static struct gt_timer_data __init *arch_timer_mem_get_timer(
>> + struct gt_block_data *gt_blocks)
>> +{
>> + struct gt_block_data *gt_block = gt_blocks;
>> + struct gt_timer_data *best_frame = NULL;
>> + void __iomem *cntctlbase;
>> + u32 cnttidr;
>> + int i;
>> +
>> + /*
>> + * According to ARMv8 Architecture Reference Manual(ARM),
>> + * the size of CNTCTLBase frame of memory-mapped timer
>> + * is SZ_4K(Offset 0x000 – 0xFFF).
>> + */
>> + cntctlbase = ioremap(gt_block->cntctlbase_phy, SZ_4K);
>> + if (!cntctlbase) {
>> + pr_err("Failed to map mem timer control frame base address\n");
>> + return NULL;
>> + }
>> + cnttidr = readl_relaxed(cntctlbase + CNTTIDR);
>> +
>> + /*
>> + * Try to find a virtual capable frame. Otherwise fall back to a
>> + * physical capable frame.
>> + */
>> + for (i = 0; i < gt_block->timer_count; i++) {
>> + int n;
>> + u32 cntacr;
>> +
>> + n = gt_block->timer[i].frame_nr;
>> +
>> + /* Try enabling everything, and see what sticks */
>> + cntacr = CNTACR_RFRQ | CNTACR_RWPT | CNTACR_RPCT |
>> + CNTACR_RWVT | CNTACR_RVOFF | CNTACR_RVCT;
>> + writel_relaxed(cntacr, cntctlbase + CNTACR(n));
>> + cntacr = readl_relaxed(cntctlbase + CNTACR(n));
>> +
>> + if ((cnttidr & CNTTIDR_VIRT(n)) &&
>> + !(~cntacr & (CNTACR_RWVT | CNTACR_RVCT))) {
>> + best_frame = &gt_block->timer[i];
>> + arch_timer_mem_use_virtual = true;
>> + break;
>> + }
>> +
>> + if (~cntacr & (CNTACR_RWPT | CNTACR_RPCT))
>> + continue;
>> +
>> + best_frame = &gt_block->timer[i];
>> + }
>> + iounmap(cntctlbase);
> As I just said in my reply to the same patch in v11, all of this is
> duplicating existing infrastructure that already exists for DT. Please
> consider decoupling the core driver code from the firmware side and make
> this reusable.

Great thanks for your help, I am working on it now.
Any suggestion for other arm_arch_timer patches?

> Thanks,
>
> M.

--
Best regards,

Fu Wei
Software Engineer
Red Hat

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