[U-Boot] [PATCH 2/2] net: phy: Add gmiitorgmii converter support
Michal Simek
michal.simek at xilinx.com
Fri Jan 25 12:35:47 UTC 2019
On 24. 01. 19 18:24, Joe Hershberger wrote:
> On Thu, Jan 24, 2019 at 2:07 AM Michal Simek <michal.simek at xilinx.com> wrote:
>>
>> On 23. 01. 19 19:20, Joe Hershberger wrote:
>>> On Tue, Nov 27, 2018 at 12:20 AM Siva Durga Prasad Paladugu
>>> <siva.durga.paladugu at xilinx.com> wrote:
>>>>
>>>> This patch adds support for gmiitorgmii converter.
>>>> This converter sits between the MAC and the external phy
>>>> MAC <==> GMII2RGMII <==> RGMII_PHY.
>>>> The ethernet driver probes this bridge and this bridge driver
>>>> probes real phy driver and invokes the real phy functionalities
>>>> as requested. This bridge just needs to be configured based on
>>>> real phy negotiated speed and duplex.
>>>>
>>>> Signed-off-by: Siva Durga Prasad Paladugu <siva.durga.paladugu at xilinx.com>
>>>> Signed-off-by: Michal Simek <michal.simek at xilinx.com>
>>>> ---
>>>
>>> FYI, NI doesn't use the Xilinx adapter, we have several internal
>>> adapters... GMII to RGMII, RMII, and I believe GMII (passing through
>>> EMIO).
>>
>> ok. How do you manage them?
>
> They are managed by 2 digital lines on EMIO
ok.
>>
>>>
>>>> drivers/net/phy/Kconfig | 7 +++
>>>> drivers/net/phy/Makefile | 1 +
>>>> drivers/net/phy/phy.c | 41 ++++++++++++++
>>>> drivers/net/phy/xilinx_gmii2rgmii.c | 103 ++++++++++++++++++++++++++++++++++++
>>>> include/phy.h | 6 +++
>>>> 5 files changed, 158 insertions(+)
>>>> create mode 100644 drivers/net/phy/xilinx_gmii2rgmii.c
>>>>
>>>> diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
>>>> index 3dc0822..a68e167 100644
>>>> --- a/drivers/net/phy/Kconfig
>>>> +++ b/drivers/net/phy/Kconfig
>>>> @@ -217,6 +217,13 @@ config PHY_VITESSE
>>>> config PHY_XILINX
>>>> bool "Xilinx Ethernet PHYs support"
>>>>
>>>> +config PHY_XILINX_GMII2RGMII
>>>> + bool "Xilinx GMII to RGMII Ethernet PHYs support"
>>>> + help
>>>> + This adds support for Xilinx GMII to RGMII IP core. This IP acts
>>>> + as bridge between MAC connected over GMII and external phy that
>>>> + is connected over RGMII interface.
>>>> +
>>>> config PHY_FIXED
>>>> bool "Fixed-Link PHY"
>>>> depends on DM_ETH
>>>> diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
>>>> index 555da83..76b6197 100644
>>>> --- a/drivers/net/phy/Makefile
>>>> +++ b/drivers/net/phy/Makefile
>>>> @@ -27,6 +27,7 @@ obj-$(CONFIG_PHY_SMSC) += smsc.o
>>>> obj-$(CONFIG_PHY_TERANETICS) += teranetics.o
>>>> obj-$(CONFIG_PHY_TI) += ti.o
>>>> obj-$(CONFIG_PHY_XILINX) += xilinx_phy.o
>>>> +obj-$(CONFIG_PHY_XILINX_GMII2RGMII) += xilinx_gmii2rgmii.o
>>>> obj-$(CONFIG_PHY_VITESSE) += vitesse.o
>>>> obj-$(CONFIG_PHY_MSCC) += mscc.o
>>>> obj-$(CONFIG_PHY_FIXED) += fixed.o
>>>> diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
>>>> index 3cb2785..d02c4d8 100644
>>>> --- a/drivers/net/phy/phy.c
>>>> +++ b/drivers/net/phy/phy.c
>>>> @@ -528,6 +528,9 @@ int phy_init(void)
>>>> #ifdef CONFIG_PHY_FIXED
>>>> phy_fixed_init();
>>>> #endif
>>>> +#ifdef CONFIG_PHY_XILINX_GMII2RGMII
>>>> + phy_xilinx_gmii2rgmii_init();
>>>> +#endif
>>>
>>> I'm a bit surprised this needs to act as a unique type of device and
>>> not a normal phy driver? When the phy_id is read, what is returned?
>>> The real phy? Nothing? You change the speed by accessing MDIO?
>>
>> It is connected on mdio bus but unfortunately there is no phy_id to read
>> to be able to use that.
>>
>> https://www.xilinx.com/support/documentation/ip_documentation/gmii_to_rgmii/v4_0/pg160-gmii-to-rgmii.pdf
>> page 21
>
> That's very unfortunate. Is it not something you can have added to the IP?
This is official IP in IP catalog and there is no way to update current
version.
>>>
>>>> return 0;
>>>> }
>>>>
>>>> @@ -875,6 +878,41 @@ void phy_connect_dev(struct phy_device *phydev, struct eth_device *dev)
>>>> debug("%s connected to %s\n", dev->name, phydev->drv->name);
>>>> }
>>>>
>>>> +#ifdef CONFIG_PHY_XILINX_GMII2RGMII
>>>> +#ifdef CONFIG_DM_ETH
>>>> +static struct phy_device *phy_connect_gmii2rgmii(struct mii_dev *bus,
>>>> + struct udevice *dev,
>>>> + phy_interface_t interface)
>>>> +#else
>>>> +static struct phy_device *phy_connect_gmii2rgmii(struct mii_dev *bus,
>>>> + struct eth_device *dev,
>>>> + phy_interface_t interface)
>>>> +#endif
>>>> +{
>>>> + struct phy_device *phydev = NULL;
>>>> + int sn = dev_of_offset(dev);
>>>> + int off;
>>>> +
>>>> + while (sn > 0) {
>>>> + off = fdt_node_offset_by_compatible(gd->fdt_blob, sn,
>>>> + "xlnx,gmii-to-rgmii-1.0");
>>>
>>> This seems to be searching under the eth dev, but at least in the
>>> "linux/Documentation/devicetree/bindings/net/xilinx_gmii2rgmii.txt"
>>> docs, this is found under the mdio node. How is this supposed to
>>> handle more than one bridge?
>>
>> I haven't seen design with more than one bridge. It is really just one
>> brigde which goes to regular phy.
>
> A number of our boards have more than one, but they are not yet ported
> to modern U-Boot.
ok.
>> Regarding mdio and DT binding. I haven't seen anywhere written if phys
>> should be inside mdio node or they should be just child in controller node.
>
> I think the inconsistency is a large part of why we can't have a
> generic MDIO or ENET PHY driver class enumeration in U-Boot.
There was one attempt in past to support multiple phys on gem. I created
one patch in past to support case where you have all 4 gems on zynqmp
enabled and because there is only single MDIO line coming directy out of
PS they have to share it.
This works fine in Linux but it doesn't work with current u-boot
infrastructure.
>> I see some examples where mdio node needs to contain compatibility
>> string and there is separate driver for that.
>>
>> In dt spec nothing is written about it and also I haven't seen yaml
>> checking from Rob.
>>
>> The key point for example is to show how bridge needs description for
>> phy on the board.
>
> Sure.
>
>>>> + if (off > 0) {
>>>> + phydev = phy_device_create(bus,
>>>> + off, PHY_GMII2RGMII_ID,
>>>> + interface);
>>>> + break;
>>>> + }
>>>> + if (off == -FDT_ERR_NOTFOUND)
>>>> + sn = fdt_first_subnode(gd->fdt_blob, sn);
>>>> + else
>>>> + printf("%s: Error finding compat string:%d\n",
>>>> + __func__, off);
>>>> + }
>>>> +
>>>> + return phydev;
>>>> +}
>>>> +#endif
>>>> +
>>>> #ifdef CONFIG_PHY_FIXED
>>>> #ifdef CONFIG_DM_ETH
>>>> static struct phy_device *phy_connect_fixed(struct mii_dev *bus,
>>>> @@ -920,6 +958,9 @@ struct phy_device *phy_connect(struct mii_dev *bus, int addr,
>>>> #ifdef CONFIG_PHY_FIXED
>>>> phydev = phy_connect_fixed(bus, dev, interface);
>>>> #endif
>>>> +#ifdef CONFIG_PHY_XILINX_GMII2RGMII
>>>> + phydev = phy_connect_gmii2rgmii(bus, dev, interface);
>>>> +#endif
>>>>
>>>> if (!phydev)
>>>> phydev = phy_find_by_mask(bus, 1 << addr, interface);
>>>> diff --git a/drivers/net/phy/xilinx_gmii2rgmii.c b/drivers/net/phy/xilinx_gmii2rgmii.c
>>>> new file mode 100644
>>>> index 0000000..aa4ce86
>>>> --- /dev/null
>>>> +++ b/drivers/net/phy/xilinx_gmii2rgmii.c
>>>> @@ -0,0 +1,103 @@
>>>> +// SPDX-License-Identifier: GPL-2.0
>>>> +/*
>>>> + * Xilinx GMII2RGMII phy driver
>>>> + *
>>>> + * Copyright (C) 2018 Xilinx, Inc.
>>>> + */
>>>> +
>>>> +#include <dm.h>
>>>> +#include <phy.h>
>>>> +#include <config.h>
>>>> +#include <common.h>
>>>> +
>>>> +DECLARE_GLOBAL_DATA_PTR;
>>>> +
>>>> +#define ZYNQ_GMII2RGMII_REG 0x10
>>>> +#define ZYNQ_GMII2RGMII_SPEED_MASK (BMCR_SPEED1000 | BMCR_SPEED100)
>>>> +
>>>> +static int xilinxgmiitorgmii_config(struct phy_device *phydev)
>>>> +{
>>>> + struct phy_device *ext_phydev = phydev->priv;
>>>> +
>>>> + debug("%s\n", __func__);
>>>> + if (ext_phydev->drv->config)
>>>> + ext_phydev->drv->config(ext_phydev);
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static int xilinxgmiitorgmii_startup(struct phy_device *phydev)
>>>> +{
>>>> + u16 val = 0;
>>>> + struct phy_device *ext_phydev = phydev->priv;
>>>> +
>>>> + debug("%s\n", __func__);
>>>> + ext_phydev->dev = phydev->dev;
>>>> + if (ext_phydev->drv->startup)
>>>> + ext_phydev->drv->startup(ext_phydev);
>>>> +
>>>> + val = phy_read(phydev, phydev->addr, ZYNQ_GMII2RGMII_REG);
>>>
>>> This seems to imply that the bridge IP is actually on MDIO at a
>>> separate address from the real phy, but the same MDIO bus.
>>
>> yes. They are both on the same bus and that's how it is designed. I was
>> looking in past if there is a code in u-boot for handling several phys
>> on the same bus and this is not in place.
>>
>> That's why even cases like this
>> eth0 -> mdio -> phy_for_eth0, phy_for_eth1
>> eth1 without mdio bus
>
> We have exactly this example on one of our Zynq 7000 boards, and I
> expect to be able to describe that.
It is not a problem to describe it. In Linux is already handled properly
but not in u-boot.
>
>> are not supported by u-boot. At least I didn't see that code for that
>> some months ago. Or is it supported now?
>
> I have not yet tried it to know what is lacking to support it.
If you have time definitely please try it. Normally if you have multiple
ethernet controllers you don't want to use all of them for booting. You
choose one with attached phy and all is good.
>>>
>>>> + val &= ~ZYNQ_GMII2RGMII_SPEED_MASK;
>>>> +
>>>> + if (ext_phydev->speed == SPEED_1000)
>>>> + val |= BMCR_SPEED1000;
>>>> + else if (ext_phydev->speed == SPEED_100)
>>>> + val |= BMCR_SPEED100;
>>>> +
>>>> + phy_write(phydev, phydev->addr, ZYNQ_GMII2RGMII_REG, val |
>>>> + BMCR_FULLDPLX);
>>>> +
>>>> + phydev->duplex = ext_phydev->duplex;
>>>> + phydev->speed = ext_phydev->speed;
>>>> + phydev->link = ext_phydev->link;
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static int xilinxgmiitorgmii_probe(struct phy_device *phydev)
>>>> +{
>>>> + int ofnode = phydev->addr;
>>>> + u32 phy_of_handle;
>>>> + int ext_phyaddr = -1;
>>>> +
>>>> + debug("%s\n", __func__);
>>>> +
>>>> + /*
>>>> + * Read the phy address again as the one we read in ethernet driver
>>>> + * was overwritten for the purpose of storing the ofnode
>>>> + */
>>>> + phydev->addr = fdtdec_get_int(gd->fdt_blob, ofnode, "reg", -1);
>>>
>>> Is this phyaddr made up? Or is this IP actually listening on a
>>> specific address on MDIO?
>>
>> this IP is in xilinx catalog and you can setup whatever number you want.
>
> OK, so the IP configuration and the DTS just need to match.
yep.
>>>
>>>> + phy_of_handle = fdtdec_lookup_phandle(gd->fdt_blob, ofnode,
>>>> + "phy-handle");
>>>> + if (phy_of_handle > 0)
>>>> + ext_phyaddr = fdtdec_get_int(gd->fdt_blob,
>>>> + phy_of_handle,
>>>> + "reg", -1);
>>>
>>> I'd like to see a xilinx_gmii2rgmii.txt added to describe how the
>>> device tree is expected to be written. The one in Linux seems a bit
>>> incomplete, also. For instance, does the phy-handle in the ethmac node
>>> point to the bridge? Is it just missing? No mention.
>>
>> I have sent you wiring for zc1275-revB
>>
>> Here is that fragment. Phy in root points to bridge. Bridge points to
>> phy on the board.
>>
>> +&gem1 {
>> + status = "okay";
>> + phy-mode = "gmii";
>> + phy-handle = <&gmiitorgmii>;
>> + phy: ethernet-phy at 0 {
>> + reg = <0x0>;
>> + };
>> + gmiitorgmii: gmiitorgmii at 8 {
>> + compatible = "xlnx,gmii-to-rgmii-1.0";
>> + reg = <8>;
>> + phy-handle = <&phy>;
>> + };
>> +};
>> +
>
> That looks reasonable.
>
>> We can extend that binding in the kernel if it is not clear.
>> Just let me know.
>
> It would be good to have the binding include the relationship to the
> gem as well.
This should work in the same way with other ethernet controllers. I
haven't tried that myself but I can't see an issue if you connect this
with others ethernet controllers. You point to bridge and bridge points
to phy in the same way.
Thanks,
Michal
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