[RFC PATCH 2/2] lib: utils/timer: Add a separate compatible for the D1 CLINT

Heinrich Schuchardt heinrich.schuchardt at canonical.com
Tue Oct 19 21:25:48 PDT 2021


On 10/20/21 05:10, Guo Ren wrote:
> On Wed, Oct 20, 2021 at 9:58 AM Samuel Holland <samuel at sholland.org> wrote:
>>
>> The CLINT in the Allwinner D1 SoC apparently does not support 64-bit
>> MMIO access. A property was added to support this quirk (and that
>> property was copied to the ACLINT MTIMER code). However, since this
>> difference in behavior makes the D1 CLINT incompatible with the SiFive
>> CLINT's programming interface, a better solution is to use a separate
>> compatible string.
>>
>> Signed-off-by: Samuel Holland <samuel at sholland.org>
>> ---
>>   docs/platform/thead-c9xx.md        |  4 +--
>>   lib/utils/ipi/fdt_ipi_mswi.c       |  1 +
>>   lib/utils/timer/fdt_timer_mtimer.c | 39 +++++++++++++++++++-----------
>>   3 files changed, 27 insertions(+), 17 deletions(-)
>>
>> diff --git a/docs/platform/thead-c9xx.md b/docs/platform/thead-c9xx.md
>> index 3490ed5..ced784d 100644
>> --- a/docs/platform/thead-c9xx.md
>> +++ b/docs/platform/thead-c9xx.md
>> @@ -52,12 +52,11 @@ DTS Example1: (Single core, eg: Allwinner D1 - c906)
>>                  ranges;
>>
>>                  clint0: clint at 14000000 {
>> -                       compatible = "riscv,clint0";
>> +                       compatible = "allwinner,sun20i-d1-clint";
>>                          interrupts-extended = <
>>                                  &cpu0_intc  3 &cpu0_intc  7
>>                                  >;
>>                          reg = <0x0 0x14000000 0x0 0x04000000>;
>> -                       clint,has-no-64bit-mmio;
>>                  };
>>
>>                  intc: interrupt-controller at 10000000 {
>> @@ -163,7 +162,6 @@ DTS Example2: (Multi cores with soc reset-regs)
>>                                  &cpu4_intc  3 &cpu4_intc  7
>>                                  >;
>>                          reg = <0xff 0xdc000000 0x0 0x04000000>;
>> -                       clint,has-no-64bit-mmio;
> Could we still keep clint,has-no-64bit-mmio for compatible? It has
> been widely used in our customers' dts.

We need a description of the T-HEAD clint that is acceptable for the 
Linux kernel.

According to the discussion in
https://lore.kernel.org/all/CAAhSdy3JU6jitTWFk4CVRG5Xc7P7ueZzd=xmnKBNpx8eGaR6hw@mail.gmail.com/
we shall drop "clint,has-no-64bit-mmio;"

In 
https://lore.kernel.org/all/7361287f-9c07-8b76-d405-35f287ac1706@canonical.com/ 
it was suggested to use
}
compatible = {"allwinner,sun20i-d1-clint", "thead,clint0"}.

Should we check on "thead,clint0" in the code?

Best regards

Heinrich

> 
>>                  };
>>
>>                  intc: interrupt-controller at ffd8000000 {
>> diff --git a/lib/utils/ipi/fdt_ipi_mswi.c b/lib/utils/ipi/fdt_ipi_mswi.c
>> index 0176941..af69e16 100644
>> --- a/lib/utils/ipi/fdt_ipi_mswi.c
>> +++ b/lib/utils/ipi/fdt_ipi_mswi.c
>> @@ -54,6 +54,7 @@ static int ipi_mswi_cold_init(void *fdt, int nodeoff,
>>   static const unsigned long clint_offset = CLINT_MSWI_OFFSET;
>>
>>   static const struct fdt_match ipi_mswi_match[] = {
>> +       { .compatible = "allwinner,sun20i-d1-clint", .data = &clint_offset },
>>          { .compatible = "riscv,clint0", .data = &clint_offset },
>>          { .compatible = "sifive,clint0", .data = &clint_offset },
>>          { .compatible = "riscv,aclint-mswi" },
>> diff --git a/lib/utils/timer/fdt_timer_mtimer.c b/lib/utils/timer/fdt_timer_mtimer.c
>> index 1ad8508..e140567 100644
>> --- a/lib/utils/timer/fdt_timer_mtimer.c
>> +++ b/lib/utils/timer/fdt_timer_mtimer.c
>> @@ -15,6 +15,11 @@
>>
>>   #define MTIMER_MAX_NR                  16
>>
>> +struct timer_mtimer_quirks {
>> +       unsigned int    mtime_offset;
>> +       bool            has_64bit_mmio;
>> +};
>> +
>>   static unsigned long mtimer_count = 0;
>>   static struct aclint_mtimer_data mtimer[MTIMER_MAX_NR];
>>   static struct aclint_mtimer_data *mt_reference = NULL;
>> @@ -23,7 +28,7 @@ static int timer_mtimer_cold_init(void *fdt, int nodeoff,
>>                                    const struct fdt_match *match)
>>   {
>>          int i, rc;
>> -       unsigned long offset, addr[2], size[2];
>> +       unsigned long addr[2], size[2];
>>          struct aclint_mtimer_data *mt;
>>
>>          if (MTIMER_MAX_NR <= mtimer_count)
>> @@ -43,28 +48,25 @@ static int timer_mtimer_cold_init(void *fdt, int nodeoff,
>>                  return rc;
>>
>>          if (match->data) { /* SiFive CLINT */
>> +               const struct timer_mtimer_quirks *quirks = match->data;
>> +
>>                  /* Set CLINT addresses */
>>                  mt->mtimecmp_addr = addr[0] + ACLINT_DEFAULT_MTIMECMP_OFFSET;
>>                  mt->mtimecmp_size = ACLINT_DEFAULT_MTIMECMP_SIZE;
>>                  mt->mtime_addr = addr[0] + ACLINT_DEFAULT_MTIME_OFFSET;
>>                  mt->mtime_size = size[0] - mt->mtimecmp_size;
>>                  /* Adjust MTIMER address and size for CLINT device */
>> -               offset = *((unsigned long *)match->data);
>> -               mt->mtime_addr += offset;
>> -               mt->mtimecmp_addr += offset;
>> -               mt->mtime_size -= offset;
>> -               /* Parse additional CLINT properties */
>> -               if (fdt_getprop(fdt, nodeoff, "clint,has-no-64bit-mmio", &rc))
>> -                       mt->has_64bit_mmio = false;
>> +               mt->mtime_addr += quirks->mtime_offset;
>> +               mt->mtimecmp_addr += quirks->mtime_offset;
>> +               mt->mtime_size -= quirks->mtime_offset;
>> +               /* Apply additional CLINT quirks */
>> +               mt->has_64bit_mmio = quirks->has_64bit_mmio;
>>          } else { /* RISC-V ACLINT MTIMER */
>>                  /* Set ACLINT MTIMER addresses */
>>                  mt->mtime_addr = addr[0];
>>                  mt->mtime_size = size[0];
>>                  mt->mtimecmp_addr = addr[1];
>>                  mt->mtimecmp_size = size[1];
>> -               /* Parse additional ACLINT MTIMER properties */
>> -               if (fdt_getprop(fdt, nodeoff, "mtimer,no-64bit-mmio", &rc))
>> -                       mt->has_64bit_mmio = false;
> Dito.
> 
>>          }
>>
>>          /* Check if MTIMER device has shared MTIME address */
>> @@ -107,11 +109,20 @@ static int timer_mtimer_cold_init(void *fdt, int nodeoff,
>>          return 0;
>>   }
>>
>> -static unsigned long clint_offset = CLINT_MTIMER_OFFSET;
>> +static const struct timer_mtimer_quirks d1_clint_quirks = {
>> +       .mtime_offset   = CLINT_MTIMER_OFFSET,
>> +       .has_64bit_mmio = false,
>> +};
>> +
>> +static const struct timer_mtimer_quirks sifive_clint_quirks = {
>> +       .mtime_offset   = CLINT_MTIMER_OFFSET,
>> +       .has_64bit_mmio = true,
>> +};
>>
>>   static const struct fdt_match timer_mtimer_match[] = {
>> -       { .compatible = "riscv,clint0", .data = &clint_offset },
>> -       { .compatible = "sifive,clint0", .data = &clint_offset },
>> +       { .compatible = "allwinner,sun20i-d1-clint", .data = &d1_clint_quirks },
>> +       { .compatible = "riscv,clint0", .data = &sifive_clint_quirks },
>> +       { .compatible = "sifive,clint0", .data = &sifive_clint_quirks },
>>          { .compatible = "riscv,aclint-mtimer" },
>>          { },
>>   };
>> --
>> 2.32.0
>>
> 
> 



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