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Message-ID: <9547b11d-147d-5029-0abe-8bf0f705c959@gmail.com>
Date: Fri, 23 Mar 2018 14:51:19 -0700
From: Florian Fainelli <f.fainelli@...il.com>
To: Alexandre Belloni <alexandre.belloni@...tlin.com>,
"David S . Miller" <davem@...emloft.net>
Cc: Allan Nielsen <Allan.Nielsen@...rosemi.com>,
razvan.stefanescu@....com, po.liu@....com,
Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
Andrew Lunn <andrew@...n.ch>, netdev@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-mips@...ux-mips.org
Subject: Re: [PATCH net-next 3/8] net: mscc: Add MDIO driver
On 03/23/2018 01:11 PM, Alexandre Belloni wrote:
> Add a driver for the Microsemi MII Management controller (MIIM) found on
> Microsemi SoCs.
> On Ocelot, there are two controllers, one is connected to the internal
> PHYs, the other one can communicate with external PHYs.
>
> Signed-off-by: Alexandre Belloni <alexandre.belloni@...tlin.com>
> ---
> drivers/net/ethernet/Kconfig | 1 +
> drivers/net/ethernet/Makefile | 1 +
> drivers/net/ethernet/mscc/Kconfig | 22 ++++
> drivers/net/ethernet/mscc/Makefile | 2 +
> drivers/net/ethernet/mscc/mscc_miim.c | 210 ++++++++++++++++++++++++++++++++++
> 5 files changed, 236 insertions(+)
> create mode 100644 drivers/net/ethernet/mscc/Kconfig
> create mode 100644 drivers/net/ethernet/mscc/Makefile
> create mode 100644 drivers/net/ethernet/mscc/mscc_miim.c
>
> diff --git a/drivers/net/ethernet/Kconfig b/drivers/net/ethernet/Kconfig
> index b6cf4b6962f5..adf643484198 100644
> --- a/drivers/net/ethernet/Kconfig
> +++ b/drivers/net/ethernet/Kconfig
> @@ -115,6 +115,7 @@ source "drivers/net/ethernet/mediatek/Kconfig"
> source "drivers/net/ethernet/mellanox/Kconfig"
> source "drivers/net/ethernet/micrel/Kconfig"
> source "drivers/net/ethernet/microchip/Kconfig"
> +source "drivers/net/ethernet/mscc/Kconfig"
> source "drivers/net/ethernet/moxa/Kconfig"
> source "drivers/net/ethernet/myricom/Kconfig"
>
> diff --git a/drivers/net/ethernet/Makefile b/drivers/net/ethernet/Makefile
> index 3cdf01e96e0b..ed7df22de7ff 100644
> --- a/drivers/net/ethernet/Makefile
> +++ b/drivers/net/ethernet/Makefile
> @@ -56,6 +56,7 @@ obj-$(CONFIG_NET_VENDOR_MEDIATEK) += mediatek/
> obj-$(CONFIG_NET_VENDOR_MELLANOX) += mellanox/
> obj-$(CONFIG_NET_VENDOR_MICREL) += micrel/
> obj-$(CONFIG_NET_VENDOR_MICROCHIP) += microchip/
> +obj-$(CONFIG_NET_VENDOR_MICROSEMI) += mscc/
> obj-$(CONFIG_NET_VENDOR_MOXART) += moxa/
> obj-$(CONFIG_NET_VENDOR_MYRI) += myricom/
> obj-$(CONFIG_FEALNX) += fealnx.o
> diff --git a/drivers/net/ethernet/mscc/Kconfig b/drivers/net/ethernet/mscc/Kconfig
> new file mode 100644
> index 000000000000..2330de6e7bb6
> --- /dev/null
> +++ b/drivers/net/ethernet/mscc/Kconfig
> @@ -0,0 +1,22 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR MIT)
> +config NET_VENDOR_MICROSEMI
> + bool "Microsemi devices"
> + default y
> + help
> + If you have a network (Ethernet) card belonging to this class, say Y.
> +
> + Note that the answer to this question doesn't directly affect the
> + kernel: saying N will just cause the configurator to skip all
> + the questions about Microsemi devices.
> +
> +if NET_VENDOR_MICROSEMI
> +
> +config MSCC_MIIM
> + tristate "Microsemi MIIM interface support"
> + depends on HAS_IOMEM
> + select PHYLIB
> + help
> + This driver supports the MIIM (MDIO) interface found in the network
> + switches of the Microsemi SoCs
> +
> +endif # NET_VENDOR_MICROSEMI
> diff --git a/drivers/net/ethernet/mscc/Makefile b/drivers/net/ethernet/mscc/Makefile
> new file mode 100644
> index 000000000000..4570e8fa4711
> --- /dev/null
> +++ b/drivers/net/ethernet/mscc/Makefile
> @@ -0,0 +1,2 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR MIT)
> +obj-$(CONFIG_MSCC_MIIM) += mscc_miim.o
> diff --git a/drivers/net/ethernet/mscc/mscc_miim.c b/drivers/net/ethernet/mscc/mscc_miim.c
> new file mode 100644
> index 000000000000..95b8d102c90f
> --- /dev/null
> +++ b/drivers/net/ethernet/mscc/mscc_miim.c
> @@ -0,0 +1,210 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR MIT)
> +/*
> + * Driver for the MDIO interface of Microsemi network switches.
> + *
> + * Author: Alexandre Belloni <alexandre.belloni@...tlin.com>
> + * Copyright (c) 2017 Microsemi Corporation
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/phy.h>
> +#include <linux/platform_device.h>
> +#include <linux/bitops.h>
> +#include <linux/io.h>
> +#include <linux/iopoll.h>
> +#include <linux/of_mdio.h>
> +
> +#define MSCC_MIIM_REG_STATUS 0x0
> +#define MSCC_MIIM_STATUS_STAT_BUSY BIT(3)
> +#define MSCC_MIIM_REG_CMD 0x8
> +#define MSCC_MIIM_CMD_OPR_WRITE BIT(1)
> +#define MSCC_MIIM_CMD_OPR_READ BIT(2)
> +#define MSCC_MIIM_CMD_WRDATA_SHIFT 4
> +#define MSCC_MIIM_CMD_REGAD_SHIFT 20
> +#define MSCC_MIIM_CMD_PHYAD_SHIFT 25
> +#define MSCC_MIIM_CMD_VLD BIT(31)
> +#define MSCC_MIIM_REG_DATA 0xC
> +#define MSCC_MIIM_DATA_ERROR (BIT(16) | BIT(17))
> +
> +#define MSCC_PHY_REG_PHY_CFG 0x0
> +#define PHY_CFG_PHY_ENA (BIT(0) | BIT(1) | BIT(2) | BIT(3))
> +#define PHY_CFG_PHY_COMMON_RESET BIT(4)
> +#define PHY_CFG_PHY_RESET (BIT(5) | BIT(6) | BIT(7) | BIT(8))
> +#define MSCC_PHY_REG_PHY_STATUS 0x4
> +
> +struct mscc_miim_dev {
> + struct mutex lock;
> + void __iomem *regs;
> + void __iomem *phy_regs;
> +};
> +
> +static int mscc_miim_wait_ready(struct mii_bus *bus)
> +{
> + struct mscc_miim_dev *miim = bus->priv;
> + u32 val;
> +
> + readl_poll_timeout(miim->regs + MSCC_MIIM_REG_STATUS, val,
> + !(val & MSCC_MIIM_STATUS_STAT_BUSY), 100, 250000);
> + if (val & MSCC_MIIM_STATUS_STAT_BUSY)
> + return -ETIMEDOUT;
> +
> + return 0;
> +}
> +
> +static int mscc_miim_read(struct mii_bus *bus, int mii_id, int regnum)
> +{
> + struct mscc_miim_dev *miim = bus->priv;
> + u32 val;
> + int ret;
> +
> + mutex_lock(&miim->lock);
What is this lock for considering that bus->lock should always be
acquired when doing these operations? As Andrew pointed out, needs to be
initialized with mutex_init(), but likely you would drop it.
> +
> + ret = mscc_miim_wait_ready(bus);
> + if (ret)
> + goto out;
> +
> + writel(MSCC_MIIM_CMD_VLD | (mii_id << MSCC_MIIM_CMD_PHYAD_SHIFT) |
> + (regnum << MSCC_MIIM_CMD_REGAD_SHIFT) | MSCC_MIIM_CMD_OPR_READ,
> + miim->regs + MSCC_MIIM_REG_CMD);
> +
> + ret = mscc_miim_wait_ready(bus);
> + if (ret)
> + goto out;
Your example had an interrupt specified, can't you use that instead of
polling?
> +
> + val = readl(miim->regs + MSCC_MIIM_REG_DATA);
> + if (val & MSCC_MIIM_DATA_ERROR) {
> + ret = -EIO;
> + goto out;
> + }
> +
> + ret = val & 0xFFFF;
> +out:
> + mutex_unlock(&miim->lock);
> + return ret;
> +}
> +
> +static int mscc_miim_write(struct mii_bus *bus, int mii_id,
> + int regnum, u16 value)
> +{
> + struct mscc_miim_dev *miim = bus->priv;
> + int ret;
> +
> + mutex_lock(&miim->lock);
> +
> + ret = mscc_miim_wait_ready(bus);
> + if (ret < 0)
> + goto out;
> +
> + writel(MSCC_MIIM_CMD_VLD | (mii_id << MSCC_MIIM_CMD_PHYAD_SHIFT) |
> + (regnum << MSCC_MIIM_CMD_REGAD_SHIFT) |
> + (value << MSCC_MIIM_CMD_WRDATA_SHIFT) |
> + MSCC_MIIM_CMD_OPR_WRITE,
> + miim->regs + MSCC_MIIM_REG_CMD);
> +
> +out:
> + mutex_unlock(&miim->lock);
> + return ret;
> +}
> +
> +static int mscc_miim_reset(struct mii_bus *bus)
> +{
> + struct mscc_miim_dev *miim = bus->priv;
> + int i;
unsigned int i
> +
> + if (miim->phy_regs) {
> + writel(0, miim->phy_regs + MSCC_PHY_REG_PHY_CFG);
> + writel(0x1ff, miim->phy_regs + MSCC_PHY_REG_PHY_CFG);
> + mdelay(500);
> + }
> +
> + for (i = 0; i < PHY_MAX_ADDR; i++) {
> + if (mscc_miim_read(bus, i, MII_PHYSID1) < 0)
> + bus->phy_mask |= BIT(i);
> + }
What is this used for? You have an OF MDIO bus which would create a
phy_device for each node specified, is this a similar workaround to what
drivers/net/phy/mdio-bcm-unimac.c has to do? If so, please document it
as such.
Other than that, this looks quite good!
--
Florian
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