lkml.org 
[lkml]   [2021]   [Jul]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH net-next] net: phy: intel-xway: Add RGMII internal delay configuration
On 2021-07-09 14:26, Russell King (Oracle) wrote:
> On Fri, Jul 09, 2021 at 01:57:26PM +0200, Martin Schiller wrote:
>> +static int xway_gphy_of_reg_init(struct phy_device *phydev)
>> +{
>> + struct device *dev = &phydev->mdio.dev;
>> + int delay_size = ARRAY_SIZE(xway_internal_delay);
>> + s32 rx_int_delay;
>> + s32 tx_int_delay;
>> + int err = 0;
>> + int val;
>> +
>> + if (phy_interface_is_rgmii(phydev)) {
>> + val = phy_read(phydev, XWAY_MDIO_MIICTRL);
>> + if (val < 0)
>> + return val;
>> + }
>> +
>> + /* Existing behavior was to use default pin strapping delay in rgmii
>> + * mode, but rgmii should have meant no delay. Warn existing users.
>> + */
>> + if (phydev->interface == PHY_INTERFACE_MODE_RGMII) {
>> + const u16 txskew = (val & XWAY_MDIO_MIICTRL_TXSKEW_MASK) >>
>> + XWAY_MDIO_MIICTRL_TXSKEW_SHIFT;
>> + const u16 rxskew = (val & XWAY_MDIO_MIICTRL_RXSKEW_MASK) >>
>> + XWAY_MDIO_MIICTRL_RXSKEW_SHIFT;
>> +
>> + if (txskew > 0 || rxskew > 0)
>> + phydev_warn(phydev,
>> + "PHY has delays (e.g. via pin strapping), but phy-mode =
>> 'rgmii'\n"
>> + "Should be 'rgmii-id' to use internal delays txskew:%x
>> rxskew:%x\n",
>> + txskew, rxskew);
>> + }
>> +
>> + /* RX delay *must* be specified if internal delay of RX is used. */
>> + if (phydev->interface == PHY_INTERFACE_MODE_RGMII_ID ||
>> + phydev->interface == PHY_INTERFACE_MODE_RGMII_RXID) {
>> + rx_int_delay = phy_get_internal_delay(phydev, dev,
>> + &xway_internal_delay[0],
>> + delay_size, true);
>> +
>> + if (rx_int_delay < 0) {
>> + phydev_err(phydev, "rx-internal-delay-ps must be specified\n");
>> + return rx_int_delay;
>> + }
>> +
>> + val &= ~XWAY_MDIO_MIICTRL_RXSKEW_MASK;
>> + val |= rx_int_delay << XWAY_MDIO_MIICTRL_RXSKEW_SHIFT;
>> + }
>> +
>> + /* TX delay *must* be specified if internal delay of TX is used. */
>> + if (phydev->interface == PHY_INTERFACE_MODE_RGMII_ID ||
>> + phydev->interface == PHY_INTERFACE_MODE_RGMII_TXID) {
>> + tx_int_delay = phy_get_internal_delay(phydev, dev,
>> + &xway_internal_delay[0],
>> + delay_size, false);
>> +
>> + if (tx_int_delay < 0) {
>> + phydev_err(phydev, "tx-internal-delay-ps must be specified\n");
>> + return tx_int_delay;
>> + }
>> +
>> + val &= ~XWAY_MDIO_MIICTRL_TXSKEW_MASK;
>> + val |= tx_int_delay << XWAY_MDIO_MIICTRL_TXSKEW_SHIFT;
>> + }
>> +
>> + if (phydev->interface == PHY_INTERFACE_MODE_RGMII_ID ||
>> + phydev->interface == PHY_INTERFACE_MODE_RGMII_RXID ||
>> + phydev->interface == PHY_INTERFACE_MODE_RGMII_TXID)
>> + err = phy_write(phydev, XWAY_MDIO_MIICTRL, val);
>> +
>> + return err;
>> +}
>
> Please reconsider the above. Maybe something like the following would
> be better:
>
> u16 mask = 0;
> int val = 0;
>
> if (!phy_interface_is_rgmii(phydev))
> return;
>
> if (phydev->interface == PHY_INTERFACE_MODE_RGMII) {
> u16 txskew, rxskew;
>
> val = phy_read(phydev, XWAY_MDIO_MIICTRL);
> if (val < 0)
> return val;
>
> txskew = (val & XWAY_MDIO_MIICTRL_TXSKEW_MASK) >>
> XWAY_MDIO_MIICTRL_TXSKEW_SHIFT;
> rxskew = (val & XWAY_MDIO_MIICTRL_RXSKEW_MASK) >>
> XWAY_MDIO_MIICTRL_RXSKEW_SHIFT;
>
> if (txskew > 0 || rxskew > 0)
> phydev_warn(phydev,
> "PHY has delays (e.g. via pin strapping), but phy-mode =
> 'rgmii'\n"
> "Should be 'rgmii-id' to use internal delays txskew:%x
> rxskew:%x\n",
> txskew, rxskew);
> return;
> }
>
> if (phydev->interface == PHY_INTERFACE_MODE_RGMII_ID ||
> phydev->interface == PHY_INTERFACE_MODE_RGMII_RXID) {
> ...
> mask |= XWAY_MDIO_MIICTRL_RXSKEW_MASK;
> val |= rx_int_delay << XWAY_MDIO_MIICTRL_RXSKEW_SHIFT;
> }
>
> if (phydev->interface == PHY_INTERFACE_MODE_RGMII_ID ||
> phydev->interface == PHY_INTERFACE_MODE_RGMII_TXID) {
> ...
> mask |= XWAY_MDIO_MIICTRL_TXSKEW_MASK;
> val |= rx_int_delay << XWAY_MDIO_MIICTRL_TXSKEW_SHIFT;
> }
>
> return phy_modify(phydev, XWAY_MDIO_MIICTRL, mask, val);
>
> Using phy_modify() has the advantage that the read-modify-write is
> done as a locked transaction on the bus, meaning that it is atomic.
> There isn't a high cost to writing functions in a way that makes use
> of that as can be seen from the above.
>

Thanks for the hint. I'll update my patch.

\
 
 \ /
  Last update: 2021-07-09 15:03    [W:0.094 / U:0.940 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site