Re: [PATCH net-next v3 04/12] net: ethernet: oa_tc6: implement software reset

Parthiban.Veerasooran
2024-03-07T07:40:05Z

Hi Andrew,

On 07/03/24 6:05 am, Andrew Lunn wrote:
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>
>> +/* Status Register #0 */
>> +#define OA_TC6_REG_STATUS0 0x0008
>> +#define STATUS0_RESETC BIT(6) /* Reset Complete */
>> +
>> /* Control command header */
>> #define OA_TC6_CTRL_HEADER_DATA_NOT_CTRL BIT(31)
>> #define OA_TC6_CTRL_HEADER_WRITE BIT(29)
>> @@ -24,6 +34,8 @@
>> (OA_TC6_CTRL_MAX_REGISTERS *\
>> OA_TC6_CTRL_REG_VALUE_SIZE) +\
>> OA_TC6_CTRL_IGNORED_SIZE)
>> +#define STATUS0_RESETC_POLL_DELAY 5
>> +#define STATUS0_RESETC_POLL_TIMEOUT 100
>>
>> /* Internal structure for MAC-PHY drivers */
>> struct oa_tc6 {
>> @@ -279,6 +291,39 @@ int oa_tc6_write_register(struct oa_tc6 *tc6, u32 address, u32 value)
>> }
>> EXPORT_SYMBOL_GPL(oa_tc6_write_register);
>>
>> +static int oa_tc6_read_sw_reset_status(struct oa_tc6 *tc6)
>> +{
>> + u32 regval;
>> + int ret;
>> +
>> + ret = oa_tc6_read_register(tc6, OA_TC6_REG_STATUS0, &regval);
>> + if (ret)
>> + return 0;
>> +
>> + return regval;
>
> The function name does not really fit what the function does. The
> function returns OA_TC6_REG_STATUS0. I assume it has more bits in it
> than just STATUS0_RESETC. So either this function should be called
> oa_tc6_read_status0, or you should mask regval with STATUS0_RESETC, so
> that it does actually return the sw reset status.
Ok, as we do the masking in the calling function readx_poll_timeout, as
you suggested I will change the function name as oa_tc6_read_status0 in
the next version.
>
>> +static int oa_tc6_sw_reset_macphy(struct oa_tc6 *tc6)
>> +{
>> + u32 regval = RESET_SWRESET;
>> + int ret;
>> +
>> + ret = oa_tc6_write_register(tc6, OA_TC6_REG_RESET, regval);
>> + if (ret)
>> + return ret;
>> +
>> + /* Poll for soft reset complete for every 5us until 100us timeout */
>
> Is this 100us defined in the standard? It is pretty short. If it is
> not part of the standard, maybe set it to something much bigger?
No, the standard doesn't define this and it is not part of the standard.
>
> Also, polling every 5us is pretty quick. I doubt most systems can even
> sleep that short a time. So maybe 1ms between polls, and 1 second
> before -ETIMEDOUT?
Ok, I agree with your proposal and will change the poll delay as 1ms
with the poll timeout of 1 second.

Best regards,
Parthiban V
>
>> + ret = readx_poll_timeout(oa_tc6_read_sw_reset_status, tc6, regval,
>> + regval & STATUS0_RESETC,
>> + STATUS0_RESETC_POLL_DELAY,
>> + STATUS0_RESETC_POLL_TIMEOUT);
>> + if (ret)
>> + return -ENODEV;
>> +
>> + /* Clear the reset complete status */
>> + return oa_tc6_write_register(tc6, OA_TC6_REG_STATUS0, regval);
>
> Andrew
>