On Wed, Dec 13, 2017 at 3:10 AM, Andrew Lunn <and...@lunn.ch> wrote:
>> +void xcv_init_hw(int phy_mode)
>> {
>> u64 cfg;
>>
>> @@ -81,12 +81,31 @@ void xcv_init_hw(void)
>> /* Wait for DLL to lock */
>> msleep(1);
>>
>> - /* Configure DLL - enable or bypass
>> - * TX no bypass, RX bypass
>> - */
>> + /* enable/bypass DLL providing MAC based internal TX/RX delays */
>> cfg = readq_relaxed(xcv->reg_base + XCV_DLL_CTL);
>> - cfg &= ~0xFF03;
>> - cfg |= CLKRX_BYP;
>> + cfg &= ~0xffff00;
>> + switch (phy_mode) {
>> + /* RX and TX delays are added by the MAC */
>> + case PHY_INTERFACE_MODE_RGMII:
>> + break;
>> + /* internal RX and TX delays provided by the PHY */
>> + case PHY_INTERFACE_MODE_RGMII_ID:
>> + cfg |= CLKRX_BYP;
>> + cfg |= CLKTX_BYP;
>> + break;
>> + /* internal RX delay provided by the PHY, the MAC
>> + * should not add an RX delay in this case
>> + */
>> + case PHY_INTERFACE_MODE_RGMII_RXID:
>> + cfg |= CLKRX_BYP;
>> + break;
>> + /* internal TX delay provided by the PHY, the MAC
>> + * should not add an TX delay in this case
>> + */
>> + case PHY_INTERFACE_MODE_RGMII_TXID:
>> + cfg |= CLKRX_BYP;
>> + break;
>> + }
>
> Hi Tim
>
> This i don't get. Normally, you leave the PHY to handle delays, if
> needed. The MAC should not add any. Here you seem to assume a delay is
> always needed, and if the PHY is not providing it, the MAC should.
>
> Andrew
Andrew,
The thunder RGX inserts a delay via an on-board DLL. The 'bypass'
register will bypass this DLL and not insert a delay from the MAC
side. By default out of reset CLKTX_BYP=1 causing the RGX transmit
interface to not introduce a delay and CLKRX_BYP=0 causing the RGX
receive interface to introduce a delay.
The current code assumes the opposite setting CLKRX_BYP and clearing
CLKTX_BYP such that the RGX interface introduces a TX delay but not RX
which would be appropriate for
PHY_INTERFACE_MODE_RGMII_RXID/rgmii-txid (right, or is my logic there
backwards?). I may have my commit msg wrong in this case.
At any rate, I've got a board where the phy provides both TX/RX delay
and thus I don't want the RGX to insert any delays which means I need
to set both CLKRX_BYP and CLKTX_BYP which the driver currently doesn't
support.
Tim
