Messages in this thread | | | Date | Sun, 12 May 2019 22:41:32 -0700 | From | Guenter Roeck <> | Subject | Re: [PATCH v2 1/2] net: phy: realtek: Add rtl8211e rx/tx delays config |
| |
Hi,
On Sat, Apr 27, 2019 at 12:21:11AM +0300, Serge Semin wrote: > There are two chip pins named TXDLY and RXDLY which actually adds the 2ns > delays to TXC and RXC for TXD/RXD latching. Alas this is the only > documented info regarding the RGMII timing control configurations the PHY > provides. It turns out the same settings can be setup via MDIO registers > hidden in the extension pages layout. Particularly the extension page 0xa4 > provides a register 0x1c, which bits 1 and 2 control the described delays. > They are used to implement the "rgmii-{id,rxid,txid}" phy-mode. > > The hidden RGMII configs register utilization was found in the rtl8211e > U-boot driver: > https://elixir.bootlin.com/u-boot/v2019.01/source/drivers/net/phy/realtek.c#L99 > > There is also a freebsd-folks discussion regarding this register: > https://reviews.freebsd.org/D13591 > > It confirms that the register bits field must control the so called > configuration pins described in the table 12-13 of the official PHY > datasheet: > 8:6 = PHY Address > 5:4 = Auto-Negotiation > 3 = Interface Mode Select > 2 = RX Delay > 1 = TX Delay > 0 = SELRGV > > Signed-off-by: Serge Semin <fancer.lancer@gmail.com> > Reviewed-by: Andrew Lunn <andrew@lunn.ch>
This patch results in a crash when running arm:ast2500-evb in qemu.
[ 4.894572] [00000000] *pgd=00000000 [ 4.895329] Internal error: Oops: 80000005 [#1] ARM [ 4.896066] CPU: 0 PID: 1 Comm: swapper Not tainted 5.1.0-09698-g1fb3b52 #1 [ 4.896364] Hardware name: Generic DT based system [ 4.896823] PC is at 0x0 [ 4.897037] LR is at phy_select_page+0x3c/0x7c
Debugging shows that phydev->drv->write_page and phydev->drv->read_page are NULL, so the crash isn't entirely surprising.
What I don't understand is how this can work in the first place. The modified entry in realtek_drvs[] doesn't have read_page/write_page functions defined, yet rtl8211e_config_init() depends on it. What am I missing here ?
Thanks, Guenter
| |