Subject: RE: [PATCH net-next v3 6/8] net: pcs: Add 10GBASE-R mode for Synopsys Designware XPCS

From: Jiawen Wu <[email-masked]>
Date: Thu, 20 Apr 2023 16:38:48 +0800

On Thursday, April 20, 2023 4:03 PM, Vladimir Oltean wrote:
> On Thu, Apr 20, 2023 at 09:56:26AM +0800, Jiawen Wu wrote:
> > On Wednesday, April 19, 2023 9:20 PM, Vladimir Oltean wrote:
> > > On Wed, Apr 19, 2023 at 04:27:37PM +0800, Jiawen Wu wrote:
> > > > Add basic support for XPCS using 10GBASE-R interface. This mode will
> > > > be extended to use interrupt, so set pcs.poll false. And avoid soft
> > > > reset so that the device using this mode is in the default configuration.
> > >
> > > I'm not clear why the xpcs_soft_reset() call is avoided. Isn't the
> > > out-of-reset configuration the "default" one?
> >
> > Theoretically so, I need to configure 10GBASE-R mode after reset. But this
> > configuration involves board info to configure PMA, etc., I'd like to implement
> > it in the next patch. Now the "default" configuration refers to the mode in
> > which the firmware is configured.
> 
> How much extra complexity are we talking about, to not depend on the
> configuration done by the bootloader?
> 

It needs to implement compat->pma_config, and add a flag in struct dw_xpcs
to indicate board with specific pma configuration. For 10GBASE-R interface, it
relatively simple, but a bit more complicate for 1000BASE-X since there are
logic conflicts in xpcs_do_config(), I haven't resolved yet.

In addition, reconfiguring XPCS will cause some known issues that I need to
workaround in the ethernet driver. So I'd like to add configuration when I
implement rate switching.

There is a piece codes for my test:

+static int xpcs_read_pma(struct dw_xpcs *xpcs, int reg)
+{
+	return xpcs_read(xpcs, MDIO_MMD_PMAPMD, DW_PMA_MMD + reg);
+}
+
+static int xpcs_write_pma(struct dw_xpcs *xpcs, int reg, u16 val)
+{
+	return xpcs_write(xpcs, MDIO_MMD_PMAPMD, DW_PMA_MMD + reg, val);
+}
+
+static int xpcs_poll_power_up(struct dw_xpcs *xpcs)
+{
+	int val, ret;
+
+	/* Wait xpcs power-up good */
+	ret = read_poll_timeout(xpcs_read_vpcs, val,
+				(val & DW_VR_XS_PCS_DIG_STS_PSEQ_ST) ==
+				DW_VR_XS_PCS_DIG_STS_PSEQ_ST_GOOD,
+				10000, 1000000, false,
+				xpcs, DW_VR_XS_PCS_DIG_STS);
+	if (ret < 0)
+		pr_err("%s: xpcs power-up timeout\n", __func__);
+
+	return ret;
+}
+
+static int xpcs_pma_init_done(struct dw_xpcs *xpcs)
+{
+	int val, ret;
+
+	xpcs_write_vpcs(xpcs, DW_VR_XS_PCS_DIG_CTRL1,
+			DW_VR_XS_PCS_DIG_CTRL1_VR_RST |
+			DW_VR_XS_PCS_DIG_CTRL1_EN_VSMMD1);
+
+	/* wait pma initialization done */
+	ret = read_poll_timeout(xpcs_read_vpcs, val,
+				!(val & DW_VR_XS_PCS_DIG_CTRL1_VR_RST),
+				100000, 10000000, false,
+				xpcs, DW_VR_XS_PCS_DIG_CTRL1);
+	if (ret < 0)
+		pr_err("%s: xpcs pma initialization timeout\n", __func__);
+
+	return ret;
+}
+
+static int xpcs_10gbaser_pma_config_wx(struct dw_xpcs *xpcs)
+{
+	int val, ret;
+
+	ret = xpcs_poll_power_up(xpcs);
+	if (ret < 0)
+		return ret;
+
+	xpcs_write(xpcs, MDIO_MMD_PCS, MDIO_CTRL2, MDIO_PCS_CTRL2_10GBR);
+	val = xpcs_read(xpcs, MDIO_MMD_PMAPMD, MDIO_CTRL1);
+	val |= MDIO_CTRL1_SPEED10G;
+	xpcs_write(xpcs, MDIO_MMD_PMAPMD, MDIO_CTRL1, val);
+
+	xpcs_write_pma(xpcs, DW_VR_XS_PMA_MPLLA_CTL0, 0x21);
+	xpcs_write_pma(xpcs, DW_VR_XS_PMA_MPLLA_CTL3, 0);
+	val = xpcs_read_pma(xpcs, DW_VR_XS_PMA_TX_GENCTL1);
+	val = u16_replace_bits(val, 0x5, DW_VR_XS_PMA_TX_GENCTL1_VBOOST_LVL);
+	xpcs_write_pma(xpcs, DW_VR_XS_PMA_TX_GENCTL1, val);
+	xpcs_write_pma(xpcs, DW_VR_XS_PMA_MISC_CTL0, 0xCF00);
+	xpcs_write_pma(xpcs, DW_VR_XS_PMA_VCO_CAL_LD0, 0x549);
+	xpcs_write_pma(xpcs, DW_VR_XS_PMA_VCO_CAL_REF0, 0x29);
+	xpcs_write_pma(xpcs, DW_VR_XS_PMA_TX_RATE_CTL, 0);
+	xpcs_write_pma(xpcs, DW_VR_XS_PMA_RX_RATE_CTL, 0);
+	xpcs_write_pma(xpcs, DW_VR_XS_PMA_TX_GEN_CTL2, 0x300);
+	xpcs_write_pma(xpcs, DW_VR_XS_PMA_RX_GEN_CTL2, 0x300);
+	xpcs_write_pma(xpcs, DW_VR_XS_PMA_MPLLA_CTL2, 0x600);
+
+	xpcs_write_pma(xpcs, DW_VR_XS_PMA_RX_EQ_CTL0, 0x45);
+	val = xpcs_read_pma(xpcs, DW_VR_XS_PMA_RX_EQ_ATTN_CTL);
+	val &= ~DW_VR_XS_PMA_RX_EQ_ATTN_LVL0;
+	xpcs_write_pma(xpcs, DW_VR_XS_PMA_RX_EQ_ATTN_CTL, val);
+	xpcs_write_pma(xpcs, DW_VR_XS_PMA_DFE_TAP_CTL0, 0xBE);
+	val = xpcs_read_pma(xpcs, DW_VR_XS_PMA_AFE_DFE_ENABLE);
+	val &= ~(DW_VR_XS_PMA_DFE_EN_0 | DW_VR_XS_PMA_AFE_EN_0);
+	xpcs_write_pma(xpcs, DW_VR_XS_PMA_AFE_DFE_ENABLE, val);
+	val = xpcs_read_pma(xpcs, DW_VR_XS_PMA_RX_EQ_CTL4);
+	val &= ~DW_VR_XS_PMA_RX_EQ_CTL4_CONT_ADAPT0;
+	xpcs_write_pma(xpcs, DW_VR_XS_PMA_RX_EQ_CTL4, val);
+
+	return xpcs_pma_init_done(xpcs);
+}
+
+static int xpcs_10gbaser_pma_config(struct dw_xpcs *xpcs)
+{
+	if (xpcs->flags & DW_MODEL_WANGXUN_SP)
+		return xpcs_10gbaser_pma_config_wx(xpcs);
+
+	return 0;
+}
+