diff mbox series

[net-next,3/5] net: pcs: add new PCS driver for altera TSE PCS

Message ID 20220826135451.526756-4-maxime.chevallier@bootlin.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series net: altera: tse: phylink conversion | expand

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netdev/fixes_present success Fixes tag not required for -next series
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netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers success CCed 9 of 9 maintainers
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch warning CHECK: Prefer using the BIT macro
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Maxime Chevallier Aug. 26, 2022, 1:54 p.m. UTC 
The Altera Triple Speed Ethernet has a SGMII/1000BaseC PCS that can be
integrated in several ways. It can either be part of the TSE MAC's
address space, accessed through 32 bits accesses on the mapped mdio
device 0, or through a dedicated 16 bits register set.

This driver allows using the TSE PCS outside of altera TSE's driver,
since it can be used standalone by other MACs.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
 MAINTAINERS                      |   7 ++
 drivers/net/pcs/Kconfig          |   6 ++
 drivers/net/pcs/Makefile         |   1 +
 drivers/net/pcs/pcs-altera-tse.c | 162 +++++++++++++++++++++++++++++++
 include/linux/pcs-altera-tse.h   |  17 ++++
 5 files changed, 193 insertions(+)
 create mode 100644 drivers/net/pcs/pcs-altera-tse.c
 create mode 100644 include/linux/pcs-altera-tse.h

Comments

Russell King (Oracle) Aug. 26, 2022, 4:45 p.m. UTC | #1 
On Fri, Aug 26, 2022 at 03:54:49PM +0200, Maxime Chevallier wrote:
> +
> +/* SGMII PCS register addresses
> + */
> +#define SGMII_PCS_SCRATCH	0x10
> +#define SGMII_PCS_REV		0x11
> +#define SGMII_PCS_LINK_TIMER_0	0x12
> +#define   SGMII_PCS_LINK_TIMER_REG(x)		(0x12 + (x))
> +#define SGMII_PCS_LINK_TIMER_1	0x13
> +#define SGMII_PCS_IF_MODE	0x14
> +#define   PCS_IF_MODE_SGMII_ENA		BIT(0)
> +#define   PCS_IF_MODE_USE_SGMII_AN	BIT(1)
> +#define   PCS_IF_MODE_SGMI_SPEED_MASK	GENMASK(3, 2)
> +#define   PCS_IF_MODE_SGMI_SPEED_10	(0 << 2)
> +#define   PCS_IF_MODE_SGMI_SPEED_100	(1 << 2)
> +#define   PCS_IF_MODE_SGMI_SPEED_1000	(2 << 2)
> +#define   PCS_IF_MODE_SGMI_HALF_DUPLEX	BIT(4)
> +#define   PCS_IF_MODE_SGMI_PHY_AN	BIT(5)

This looks very similar to pcs-lynx's register layout. I wonder if it's
the same underlying hardware.

> +static int alt_tse_pcs_config(struct phylink_pcs *pcs, unsigned int mode,
> +			      phy_interface_t interface,
> +			      const unsigned long *advertising,
> +			      bool permit_pause_to_mac)
> +{
> +	struct altera_tse_pcs *tse_pcs = phylink_pcs_to_tse_pcs(pcs);
> +	u32 ctrl, if_mode;
> +
> +	if (interface != PHY_INTERFACE_MODE_SGMII &&
> +	    interface != PHY_INTERFACE_MODE_1000BASEX)
> +		return 0;

I would suggest doing this check in .pcs_validate() to catch anyone
attaching the PCS with an unsupported interface mode.

> +static void alt_tse_pcs_an_restart(struct phylink_pcs *pcs)
> +{
> +	struct altera_tse_pcs *tse_pcs = phylink_pcs_to_tse_pcs(pcs);
> +	u16 bmcr;
> +
> +	bmcr = tse_pcs_read(tse_pcs, MII_BMCR);
> +	bmcr |= BMCR_ANRESTART;
> +	tse_pcs_write(tse_pcs, MII_BMCR, bmcr);
> +
> +	tse_pcs_reset(tse_pcs);

Any ideas why a reset is necessary after setting BMCR_ANRESTART?
Normally, this is not required.

> diff --git a/include/linux/pcs-altera-tse.h b/include/linux/pcs-altera-tse.h
> new file mode 100644
> index 000000000000..9c85e7c8ef70
> --- /dev/null
> +++ b/include/linux/pcs-altera-tse.h
> @@ -0,0 +1,17 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2022 Bootlin
> + *
> + * Maxime Chevallier <maxime.chevallier@bootlin.com>
> + */
> +
> +#ifndef __LINUX_PCS_ALTERA_TSE_H
> +#define __LINUX_PCS_ALTERA_TSE_H
> +
> +struct phylink;

Don't you want "struct phylink_pcs;" here?
Maxime Chevallier Aug. 27, 2022, 9:13 a.m. UTC | #2 
Hello Russell,

On Fri, 26 Aug 2022 17:45:13 +0100
"Russell King (Oracle)" <linux@armlinux.org.uk> wrote:

> On Fri, Aug 26, 2022 at 03:54:49PM +0200, Maxime Chevallier wrote:
> > +
> > +/* SGMII PCS register addresses
> > + */
> > +#define SGMII_PCS_SCRATCH	0x10
> > +#define SGMII_PCS_REV		0x11
> > +#define SGMII_PCS_LINK_TIMER_0	0x12
> > +#define   SGMII_PCS_LINK_TIMER_REG(x)		(0x12 + (x))
> > +#define SGMII_PCS_LINK_TIMER_1	0x13
> > +#define SGMII_PCS_IF_MODE	0x14
> > +#define   PCS_IF_MODE_SGMII_ENA		BIT(0)
> > +#define   PCS_IF_MODE_USE_SGMII_AN	BIT(1)
> > +#define   PCS_IF_MODE_SGMI_SPEED_MASK	GENMASK(3, 2)
> > +#define   PCS_IF_MODE_SGMI_SPEED_10	(0 << 2)
> > +#define   PCS_IF_MODE_SGMI_SPEED_100	(1 << 2)
> > +#define   PCS_IF_MODE_SGMI_SPEED_1000	(2 << 2)
> > +#define   PCS_IF_MODE_SGMI_HALF_DUPLEX	BIT(4)
> > +#define   PCS_IF_MODE_SGMI_PHY_AN	BIT(5)  
> 
> This looks very similar to pcs-lynx's register layout. I wonder if
> it's the same underlying hardware.

I've also looked, and indeed the layout is very smiliar. The key
differences would be that the TSE PCS is limited to 1G max and 8/10bit
encoding, whereas the lynx seems to support BaseR and higher speeds.

> > +static int alt_tse_pcs_config(struct phylink_pcs *pcs, unsigned
> > int mode,
> > +			      phy_interface_t interface,
> > +			      const unsigned long *advertising,
> > +			      bool permit_pause_to_mac)
> > +{
> > +	struct altera_tse_pcs *tse_pcs =
> > phylink_pcs_to_tse_pcs(pcs);
> > +	u32 ctrl, if_mode;
> > +
> > +	if (interface != PHY_INTERFACE_MODE_SGMII &&
> > +	    interface != PHY_INTERFACE_MODE_1000BASEX)
> > +		return 0;  
> 
> I would suggest doing this check in .pcs_validate() to catch anyone
> attaching the PCS with an unsupported interface mode.

I'll add it, thanks.

> > +static void alt_tse_pcs_an_restart(struct phylink_pcs *pcs)
> > +{
> > +	struct altera_tse_pcs *tse_pcs =
> > phylink_pcs_to_tse_pcs(pcs);
> > +	u16 bmcr;
> > +
> > +	bmcr = tse_pcs_read(tse_pcs, MII_BMCR);
> > +	bmcr |= BMCR_ANRESTART;
> > +	tse_pcs_write(tse_pcs, MII_BMCR, bmcr);
> > +
> > +	tse_pcs_reset(tse_pcs);  
> 
> Any ideas why a reset is necessary after setting BMCR_ANRESTART?
> Normally, this is not required.

From my tests, this is something this block needs :/ A soft reset on
this PCS will reset the comma detection and encoding logic, and the
testing I've done needs that for proper autoneg, especially when we
switch back and forth between SGMII/1000BaseX.

The TSE PCS support in dwmac-socfpga also does it, and this was
developped independently to this driver, so it looks like folks who
worked on that also found the same behaviour...

This might be worth adding a comment then :)

> > diff --git a/include/linux/pcs-altera-tse.h
> > b/include/linux/pcs-altera-tse.h new file mode 100644
> > index 000000000000..9c85e7c8ef70
> > --- /dev/null
> > +++ b/include/linux/pcs-altera-tse.h
> > @@ -0,0 +1,17 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Copyright (C) 2022 Bootlin
> > + *
> > + * Maxime Chevallier <maxime.chevallier@bootlin.com>
> > + */
> > +
> > +#ifndef __LINUX_PCS_ALTERA_TSE_H
> > +#define __LINUX_PCS_ALTERA_TSE_H
> > +
> > +struct phylink;  
> 
> Don't you want "struct phylink_pcs;" here?

Oh yes indeed, I this this whole line isn't necessary at all as a
matter of fact :/

Thanks for the review,

Maxime
diff mbox series

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index ba954d5a9a2f..20bcfff8626d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -878,6 +878,13 @@  L:	netdev@vger.kernel.org
 S:	Maintained
 F:	drivers/net/ethernet/altera/
 
+ALTERA TSE PCS
+M:	Maxime Chevallier <maxime.chevallier@bootlin.com>
+L:	netdev@vger.kernel.org
+S:	Supported
+F:	drivers/net/pcs/pcs-altera-tse.c
+F:	include/linux/pcs-altera-tse.h
+
 ALTERA UART/JTAG UART SERIAL DRIVERS
 M:	Tobias Klauser <tklauser@distanz.ch>
 L:	linux-serial@vger.kernel.org
diff --git a/drivers/net/pcs/Kconfig b/drivers/net/pcs/Kconfig
index 6289b7c765f1..6e7e6c346a3e 100644
--- a/drivers/net/pcs/Kconfig
+++ b/drivers/net/pcs/Kconfig
@@ -26,4 +26,10 @@  config PCS_RZN1_MIIC
 	  on RZ/N1 SoCs. This PCS converts MII to RMII/RGMII or can be set in
 	  pass-through mode for MII.
 
+config PCS_ALTERA_TSE
+	tristate
+	help
+	  This module provides helper functions for the Altera Triple Speed
+	  Ethernet SGMII PCS, that can be found on the Intel Socfpga family.
+
 endmenu
diff --git a/drivers/net/pcs/Makefile b/drivers/net/pcs/Makefile
index 0ff5388fcdea..4c780d8f2e98 100644
--- a/drivers/net/pcs/Makefile
+++ b/drivers/net/pcs/Makefile
@@ -6,3 +6,4 @@  pcs_xpcs-$(CONFIG_PCS_XPCS)	:= pcs-xpcs.o pcs-xpcs-nxp.o
 obj-$(CONFIG_PCS_XPCS)		+= pcs_xpcs.o
 obj-$(CONFIG_PCS_LYNX)		+= pcs-lynx.o
 obj-$(CONFIG_PCS_RZN1_MIIC)	+= pcs-rzn1-miic.o
+obj-$(CONFIG_PCS_ALTERA_TSE)	+= pcs-altera-tse.o
diff --git a/drivers/net/pcs/pcs-altera-tse.c b/drivers/net/pcs/pcs-altera-tse.c
new file mode 100644
index 000000000000..d9794a5e5443
--- /dev/null
+++ b/drivers/net/pcs/pcs-altera-tse.c
@@ -0,0 +1,162 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2022 Bootlin
+ *
+ * Maxime Chevallier <maxime.chevallier@bootlin.com>
+ */
+
+#include <linux/netdevice.h>
+#include <linux/phy.h>
+#include <linux/phylink.h>
+#include <linux/pcs-altera-tse.h>
+
+/* SGMII PCS register addresses
+ */
+#define SGMII_PCS_SCRATCH	0x10
+#define SGMII_PCS_REV		0x11
+#define SGMII_PCS_LINK_TIMER_0	0x12
+#define   SGMII_PCS_LINK_TIMER_REG(x)		(0x12 + (x))
+#define SGMII_PCS_LINK_TIMER_1	0x13
+#define SGMII_PCS_IF_MODE	0x14
+#define   PCS_IF_MODE_SGMII_ENA		BIT(0)
+#define   PCS_IF_MODE_USE_SGMII_AN	BIT(1)
+#define   PCS_IF_MODE_SGMI_SPEED_MASK	GENMASK(3, 2)
+#define   PCS_IF_MODE_SGMI_SPEED_10	(0 << 2)
+#define   PCS_IF_MODE_SGMI_SPEED_100	(1 << 2)
+#define   PCS_IF_MODE_SGMI_SPEED_1000	(2 << 2)
+#define   PCS_IF_MODE_SGMI_HALF_DUPLEX	BIT(4)
+#define   PCS_IF_MODE_SGMI_PHY_AN	BIT(5)
+#define SGMII_PCS_DIS_READ_TO	0x15
+#define SGMII_PCS_READ_TO	0x16
+#define SGMII_PCS_SW_RESET_TIMEOUT 100 /* usecs */
+
+struct altera_tse_pcs {
+	struct phylink_pcs pcs;
+	void __iomem *base;
+	int reg_width;
+};
+
+static struct altera_tse_pcs *phylink_pcs_to_tse_pcs(struct phylink_pcs *pcs)
+{
+	return container_of(pcs, struct altera_tse_pcs, pcs);
+}
+
+static u16 tse_pcs_read(struct altera_tse_pcs *tse_pcs, int regnum)
+{
+	if (tse_pcs->reg_width == 4)
+		return readl(tse_pcs->base + regnum * 4);
+	else
+		return readw(tse_pcs->base + regnum * 2);
+}
+
+static void tse_pcs_write(struct altera_tse_pcs *tse_pcs, int regnum,
+			  u16 value)
+{
+	if (tse_pcs->reg_width == 4)
+		writel(value, tse_pcs->base + regnum * 4);
+	else
+		writew(value, tse_pcs->base + regnum * 2);
+}
+
+static int tse_pcs_reset(struct altera_tse_pcs *tse_pcs)
+{
+	int i = 0;
+	u16 bmcr;
+
+	/* Reset PCS block */
+	bmcr = tse_pcs_read(tse_pcs, MII_BMCR);
+	bmcr |= BMCR_RESET;
+	tse_pcs_write(tse_pcs, MII_BMCR, bmcr);
+
+	for (i = 0; i < SGMII_PCS_SW_RESET_TIMEOUT; i++) {
+		if (!(tse_pcs_read(tse_pcs, MII_BMCR) & BMCR_RESET))
+			return 0;
+		udelay(1);
+	}
+
+	return -ETIMEDOUT;
+}
+
+static int alt_tse_pcs_config(struct phylink_pcs *pcs, unsigned int mode,
+			      phy_interface_t interface,
+			      const unsigned long *advertising,
+			      bool permit_pause_to_mac)
+{
+	struct altera_tse_pcs *tse_pcs = phylink_pcs_to_tse_pcs(pcs);
+	u32 ctrl, if_mode;
+
+	if (interface != PHY_INTERFACE_MODE_SGMII &&
+	    interface != PHY_INTERFACE_MODE_1000BASEX)
+		return 0;
+
+	ctrl = tse_pcs_read(tse_pcs, MII_BMCR);
+	if_mode = tse_pcs_read(tse_pcs, SGMII_PCS_IF_MODE);
+
+	/* Set link timer to 1.6ms, as per the MegaCore Function User Guide */
+	tse_pcs_write(tse_pcs, SGMII_PCS_LINK_TIMER_0, 0x0D40);
+	tse_pcs_write(tse_pcs, SGMII_PCS_LINK_TIMER_1, 0x03);
+
+	if (interface == PHY_INTERFACE_MODE_SGMII) {
+		if_mode |= PCS_IF_MODE_USE_SGMII_AN | PCS_IF_MODE_SGMII_ENA;
+	} else if (interface == PHY_INTERFACE_MODE_1000BASEX) {
+		if_mode &= ~(PCS_IF_MODE_USE_SGMII_AN | PCS_IF_MODE_SGMII_ENA);
+		if_mode |= PCS_IF_MODE_SGMI_SPEED_1000;
+	}
+
+	ctrl |= (BMCR_SPEED1000 | BMCR_FULLDPLX | BMCR_ANENABLE);
+
+	tse_pcs_write(tse_pcs, MII_BMCR, ctrl);
+	tse_pcs_write(tse_pcs, SGMII_PCS_IF_MODE, if_mode);
+
+	return tse_pcs_reset(tse_pcs);
+}
+
+static void alt_tse_pcs_get_state(struct phylink_pcs *pcs,
+				  struct phylink_link_state *state)
+{
+	struct altera_tse_pcs *tse_pcs = phylink_pcs_to_tse_pcs(pcs);
+	u16 bmsr, lpa;
+
+	bmsr = tse_pcs_read(tse_pcs, MII_BMSR);
+	lpa = tse_pcs_read(tse_pcs, MII_LPA);
+
+	phylink_mii_c22_pcs_decode_state(state, bmsr, lpa);
+}
+
+static void alt_tse_pcs_an_restart(struct phylink_pcs *pcs)
+{
+	struct altera_tse_pcs *tse_pcs = phylink_pcs_to_tse_pcs(pcs);
+	u16 bmcr;
+
+	bmcr = tse_pcs_read(tse_pcs, MII_BMCR);
+	bmcr |= BMCR_ANRESTART;
+	tse_pcs_write(tse_pcs, MII_BMCR, bmcr);
+
+	tse_pcs_reset(tse_pcs);
+}
+
+static const struct phylink_pcs_ops alt_tse_pcs_ops = {
+	.pcs_get_state = alt_tse_pcs_get_state,
+	.pcs_config = alt_tse_pcs_config,
+	.pcs_an_restart = alt_tse_pcs_an_restart,
+};
+
+struct phylink_pcs *alt_tse_pcs_create(struct net_device *ndev,
+				       void __iomem *pcs_base, int reg_width)
+{
+	struct altera_tse_pcs *tse_pcs;
+
+	if (reg_width != 4 && reg_width != 2)
+		return ERR_PTR(-EINVAL);
+
+	tse_pcs = devm_kzalloc(&ndev->dev, sizeof(*tse_pcs), GFP_KERNEL);
+	if (!tse_pcs)
+		return ERR_PTR(-ENOMEM);
+
+	tse_pcs->pcs.ops = &alt_tse_pcs_ops;
+	tse_pcs->base = pcs_base;
+	tse_pcs->reg_width = reg_width;
+
+	return &tse_pcs->pcs;
+}
+EXPORT_SYMBOL_GPL(alt_tse_pcs_create);
diff --git a/include/linux/pcs-altera-tse.h b/include/linux/pcs-altera-tse.h
new file mode 100644
index 000000000000..9c85e7c8ef70
--- /dev/null
+++ b/include/linux/pcs-altera-tse.h
@@ -0,0 +1,17 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2022 Bootlin
+ *
+ * Maxime Chevallier <maxime.chevallier@bootlin.com>
+ */
+
+#ifndef __LINUX_PCS_ALTERA_TSE_H
+#define __LINUX_PCS_ALTERA_TSE_H
+
+struct phylink;
+struct net_device;
+
+struct phylink_pcs *alt_tse_pcs_create(struct net_device *ndev,
+				       void __iomem *pcs_base, int reg_width);
+
+#endif /* __LINUX_PCS_ALTERA_TSE_H */