Davinci's MDIO controller is present on other TI devices, without an
accompanying EMAC.  For example, on tnetv107x, the same MDIO module is used in
conjunction with a 3-port switch hardware.

By separating the MDIO controller code into its own platform driver, this
patch allows common logic to be reused on such platforms.

Signed-off-by: Cyril Chemparathy <cy...@ti.com>
Acked-by: David S. Miller <da...@davemloft.net>
---
 drivers/net/Kconfig          |   10 +
 drivers/net/Makefile         |    1 +
 drivers/net/davinci_mdio.c   |  386 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/davinci_emac.h |    4 +
 4 files changed, 401 insertions(+), 0 deletions(-)
 create mode 100644 drivers/net/davinci_mdio.c

diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index 2cc81a5..c5c86e0 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -958,6 +958,16 @@ config TI_DAVINCI_EMAC
          To compile this driver as a module, choose M here: the module
          will be called davinci_emac_driver.  This is recommended.
 
+config TI_DAVINCI_MDIO
+       tristate "TI DaVinci MDIO Support"
+       depends on ARM && ( ARCH_DAVINCI || ARCH_OMAP3 )
+       select PHYLIB
+       help
+         This driver supports TI's DaVinci MDIO module.
+
+         To compile this driver as a module, choose M here: the module
+         will be called davinci_mdio.  This is recommended.
+
 config DM9000
        tristate "DM9000 support"
        depends on ARM || BLACKFIN || MIPS
diff --git a/drivers/net/Makefile b/drivers/net/Makefile
index 3e8f150..d38a7ab 100644
--- a/drivers/net/Makefile
+++ b/drivers/net/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_MDIO) += mdio.o
 obj-$(CONFIG_PHYLIB) += phy/
 
 obj-$(CONFIG_TI_DAVINCI_EMAC) += davinci_emac.o
+obj-$(CONFIG_TI_DAVINCI_MDIO) += davinci_mdio.o
 
 obj-$(CONFIG_E1000) += e1000/
 obj-$(CONFIG_E1000E) += e1000e/
diff --git a/drivers/net/davinci_mdio.c b/drivers/net/davinci_mdio.c
new file mode 100644
index 0000000..d34a53a
--- /dev/null
+++ b/drivers/net/davinci_mdio.c
@@ -0,0 +1,386 @@
+/*
+ * DaVinci MDIO Module driver
+ *
+ * Copyright (C) 2010 Texas Instruments.
+ *
+ * Shamelessly ripped out of davinci_emac.c, original copyrights follow:
+ *
+ * Copyright (C) 2009 Texas Instruments.
+ *
+ * ---------------------------------------------------------------------------
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ * ---------------------------------------------------------------------------
+ */
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/phy.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/davinci_emac.h>
+
+#define PHY_REG_MASK           0x1f
+#define PHY_ID_MASK            0x1f
+
+#define DEF_OUT_FREQ           2200000         /* 2.2 MHz */
+
+struct davinci_mdio_regs {
+       u32     version;
+       u32     control;
+#define CONTROL_IDLE           BIT(31)
+#define CONTROL_ENABLE         BIT(30)
+#define CONTROL_MAX_DIV                (0xff)
+
+       u32     alive;
+       u32     link;
+       u32     linkintraw;
+       u32     linkintmasked;
+       u32     __reserved_0[2];
+       u32     userintraw;
+       u32     userintmasked;
+       u32     userintmaskset;
+       u32     userintmaskclr;
+       u32     __reserved_1[20];
+
+       struct {
+               u32     access;
+#define USERACCESS_GO          BIT(31)
+#define USERACCESS_WRITE       BIT(30)
+#define USERACCESS_ACK         BIT(29)
+#define USERACCESS_READ                (0)
+#define USERACCESS_DATA                (0xffff)
+
+               u32     physel;
+       }       user[0];
+};
+
+struct mdio_platform_data default_pdata = {
+       .bus_freq = DEF_OUT_FREQ,
+};
+
+struct davinci_mdio_data {
+       struct mdio_platform_data pdata;
+       struct davinci_mdio_regs __iomem *regs;
+       spinlock_t      lock;
+       struct clk      *clk;
+       struct device   *dev;
+       struct mii_bus  *bus;
+       bool            suspended;
+};
+
+/* wait until hardware is ready for another user access */
+static inline u32 wait_for_user_access(struct davinci_mdio_data *data)
+{
+       struct davinci_mdio_regs __iomem *regs = data->regs;
+       u32 reg;
+
+       while ((reg = __raw_readl(&regs->user[0].access)) & USERACCESS_GO)
+               ;
+
+       return reg;
+}
+
+/* wait until hardware state machine is idle */
+static inline void wait_for_idle(struct davinci_mdio_data *data)
+{
+       struct davinci_mdio_regs __iomem *regs = data->regs;
+
+       while ((__raw_readl(&regs->control) & CONTROL_IDLE) == 0)
+               ;
+}
+
+static int davinci_mdio_read(struct mii_bus *bus, int phy_id, int phy_reg)
+{
+       struct davinci_mdio_data *data = bus->priv;
+       u32 reg;
+
+       if (phy_reg & ~PHY_REG_MASK || phy_id & ~PHY_ID_MASK)
+               return -EINVAL;
+
+       spin_lock(&data->lock);
+
+       if (data->suspended) {
+               spin_unlock(&data->lock);
+               return -ENODEV;
+       }
+
+       wait_for_user_access(data);
+       reg = (USERACCESS_GO | USERACCESS_READ | (phy_reg << 21) |
+              (phy_id << 16));
+       __raw_writel(reg, &data->regs->user[0].access);
+       reg = wait_for_user_access(data);
+       spin_unlock(&data->lock);
+
+       return (reg & USERACCESS_ACK) ? (reg & USERACCESS_DATA) : -EIO;
+}
+
+static int davinci_mdio_write(struct mii_bus *bus, int phy_id,
+                             int phy_reg, u16 phy_data)
+{
+       struct davinci_mdio_data *data = bus->priv;
+       u32 reg;
+
+       if (phy_reg & ~PHY_REG_MASK || phy_id & ~PHY_ID_MASK)
+               return -EINVAL;
+
+       spin_lock(&data->lock);
+
+       if (data->suspended) {
+               spin_unlock(&data->lock);
+               return -ENODEV;
+       }
+
+       wait_for_user_access(data);
+       reg = (USERACCESS_GO | USERACCESS_WRITE | (phy_reg << 21) |
+                  (phy_id << 16) | (phy_data & USERACCESS_DATA));
+       __raw_writel(reg, &data->regs->user[0].access);
+       wait_for_user_access(data);
+       spin_unlock(&data->lock);
+
+       return 0;
+}
+
+static int __devinit davinci_mdio_probe(struct platform_device *pdev)
+{
+       struct mdio_platform_data *pdata = pdev->dev.platform_data;
+       struct device *dev = &pdev->dev;
+       struct davinci_mdio_data *data;
+       struct resource *res;
+       u32 mdio_in_freq, mdio_out_freq, div, phy_mask, ver;
+       struct phy_device *phy;
+       int ret, addr;
+
+       data = kzalloc(sizeof(*data), GFP_KERNEL);
+       if (!data) {
+               dev_err(dev, "failed to alloc device data\n");
+               return -ENOMEM;
+       }
+
+       data->pdata = pdata ? (*pdata) : default_pdata;
+
+       data->bus = mdiobus_alloc();
+       if (!data->bus) {
+               dev_err(dev, "failed to alloc mii bus\n");
+               ret = -ENOMEM;
+               goto bail_out;
+       }
+
+       data->bus->name         = dev_name(dev);
+       data->bus->read         = davinci_mdio_read,
+       data->bus->write        = davinci_mdio_write,
+       data->bus->parent       = dev;
+       data->bus->priv         = data;
+       snprintf(data->bus->id, MII_BUS_ID_SIZE, "%x", pdev->id);
+
+       data->clk = clk_get(dev, NULL);
+       if (IS_ERR(data->clk)) {
+               data->clk = NULL;
+               dev_err(dev, "failed to get device clock\n");
+               ret = PTR_ERR(data->clk);
+               goto bail_out;
+       }
+
+       clk_enable(data->clk);
+
+       dev_set_drvdata(dev, data);
+       data->dev = dev;
+       spin_lock_init(&data->lock);
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       if (!res) {
+               dev_err(dev, "could not find register map resource\n");
+               ret = -ENOENT;
+               goto bail_out;
+       }
+
+       res = devm_request_mem_region(dev, res->start, resource_size(res),
+                                           dev_name(dev));
+       if (!res) {
+               dev_err(dev, "could not allocate register map resource\n");
+               ret = -ENXIO;
+               goto bail_out;
+       }
+
+       data->regs = devm_ioremap_nocache(dev, res->start, resource_size(res));
+       if (!data->regs) {
+               dev_err(dev, "could not map mdio registers\n");
+               ret = -ENOMEM;
+               goto bail_out;
+       }
+
+       mdio_in_freq = clk_get_rate(data->clk);
+       div = (mdio_in_freq / data->pdata.bus_freq) - 1;
+       if (div > CONTROL_MAX_DIV)
+               div = CONTROL_MAX_DIV;
+       mdio_out_freq = mdio_in_freq / (div + 1);
+
+       /* set enable and clock divider */
+       __raw_writel(div | CONTROL_ENABLE, &data->regs->control);
+
+       /*
+        * wait for scan logic to settle:
+        * the scan time consists of (a) a large fixed component, and (b) a
+        * small component that varies with the mii bus frequency.  These
+        * were estimated using measurements at 1.1 and 2.2 MHz on tnetv107x
+        * silicon.  Since the effect of (b) was found to be largely
+        * negligible, we keep things simple here.
+        */
+       mdelay(1);
+
+       /* dump hardware version info */
+       ver = __raw_readl(&data->regs->version);
+       dev_info(dev, "davinci mdio revision %d.%d\n",
+                       (ver >> 8) & 0xff, ver & 0xff);
+
+       /* get phy mask from the alive register */
+       phy_mask = __raw_readl(&data->regs->alive);
+       if (phy_mask) {
+               /* restrict mdio bus to live phys only */
+               dev_info(dev, "detected phy mask %x\n", ~phy_mask);
+               phy_mask = ~phy_mask;
+       } else {
+               /* desperately scan all phys */
+               dev_warn(dev, "failed to detect live phys, scanning all\n");
+               phy_mask = 0;
+       }
+       data->bus->phy_mask = phy_mask;
+
+       /* register the mii bus */
+       ret = mdiobus_register(data->bus);
+       if (ret)
+               goto bail_out;
+
+       /* scan and dump the bus */
+       for (addr = 0; addr < PHY_MAX_ADDR; addr++) {
+               phy = data->bus->phy_map[addr];
+               if (phy) {
+                       dev_info(dev, "phy[%d]: device %s, driver %s\n",
+                                phy->addr, dev_name(&phy->dev),
+                                phy->drv ? phy->drv->name : "unknown");
+               }
+       }
+
+       return 0;
+
+bail_out:
+       if (data->bus)
+               mdiobus_free(data->bus);
+
+       if (data->clk) {
+               clk_disable(data->clk);
+               clk_put(data->clk);
+       }
+
+       kfree(data);
+
+       return ret;
+}
+
+static int __devexit davinci_mdio_remove(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct davinci_mdio_data *data = dev_get_drvdata(dev);
+
+       if (data->bus)
+               mdiobus_free(data->bus);
+
+       if (data->clk) {
+               clk_disable(data->clk);
+               clk_put(data->clk);
+       }
+
+       dev_set_drvdata(dev, NULL);
+
+       kfree(data);
+
+       return 0;
+}
+
+static int davinci_mdio_suspend(struct device *dev)
+{
+       struct davinci_mdio_data *data = dev_get_drvdata(dev);
+       u32 ctrl;
+
+       spin_lock(&data->lock);
+
+       /* shutdown the scan state machine */
+       ctrl = __raw_readl(&data->regs->control);
+       ctrl &= ~CONTROL_ENABLE;
+       __raw_writel(ctrl, &data->regs->control);
+       wait_for_idle(data);
+
+       if (data->clk)
+               clk_disable(data->clk);
+
+       data->suspended = true;
+       spin_unlock(&data->lock);
+
+       return 0;
+}
+
+static int davinci_mdio_resume(struct device *dev)
+{
+       struct davinci_mdio_data *data = dev_get_drvdata(dev);
+       u32 ctrl;
+
+       spin_lock(&data->lock);
+       if (data->clk)
+               clk_enable(data->clk);
+
+       /* restart the scan state machine */
+       ctrl = __raw_readl(&data->regs->control);
+       ctrl |= CONTROL_ENABLE;
+       __raw_writel(ctrl, &data->regs->control);
+
+       data->suspended = false;
+       spin_unlock(&data->lock);
+
+       return 0;
+}
+
+static const struct dev_pm_ops davinci_mdio_pm_ops = {
+       .suspend        = davinci_mdio_suspend,
+       .resume         = davinci_mdio_resume,
+};
+
+static struct platform_driver davinci_mdio_driver = {
+       .driver = {
+               .name    = "davinci_mdio",
+               .owner   = THIS_MODULE,
+               .pm      = &davinci_mdio_pm_ops,
+       },
+       .probe = davinci_mdio_probe,
+       .remove = __devexit_p(davinci_mdio_remove),
+};
+
+static int __init davinci_mdio_init(void)
+{
+       return platform_driver_register(&davinci_mdio_driver);
+}
+device_initcall(davinci_mdio_init);
+
+static void __exit davinci_mdio_exit(void)
+{
+       platform_driver_unregister(&davinci_mdio_driver);
+}
+module_exit(davinci_mdio_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("DaVinci MDIO driver");
diff --git a/include/linux/davinci_emac.h b/include/linux/davinci_emac.h
index 7c930db..a04fd8c 100644
--- a/include/linux/davinci_emac.h
+++ b/include/linux/davinci_emac.h
@@ -14,6 +14,10 @@
 #include <linux/if_ether.h>
 #include <linux/memory.h>
 
+struct mdio_platform_data {
+       unsigned long           bus_freq;
+};
+
 struct emac_platform_data {
        char mac_addr[ETH_ALEN];
        u32 ctrl_reg_offset;
-- 
1.7.0.4

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