diff options
Diffstat (limited to 'kernel/drivers/net/ethernet/marvell/mvmdio.c')
| -rw-r--r-- | kernel/drivers/net/ethernet/marvell/mvmdio.c | 301 |
1 files changed, 301 insertions, 0 deletions
diff --git a/kernel/drivers/net/ethernet/marvell/mvmdio.c b/kernel/drivers/net/ethernet/marvell/mvmdio.c new file mode 100644 index 000000000..fc2fb2534 --- /dev/null +++ b/kernel/drivers/net/ethernet/marvell/mvmdio.c @@ -0,0 +1,301 @@ +/* + * Driver for the MDIO interface of Marvell network interfaces. + * + * Since the MDIO interface of Marvell network interfaces is shared + * between all network interfaces, having a single driver allows to + * handle concurrent accesses properly (you may have four Ethernet + * ports, but they in fact share the same SMI interface to access + * the MDIO bus). This driver is currently used by the mvneta and + * mv643xx_eth drivers. + * + * Copyright (C) 2012 Marvell + * + * Thomas Petazzoni <thomas.petazzoni@free-electrons.com> + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/phy.h> +#include <linux/interrupt.h> +#include <linux/platform_device.h> +#include <linux/delay.h> +#include <linux/io.h> +#include <linux/clk.h> +#include <linux/of_mdio.h> +#include <linux/sched.h> +#include <linux/wait.h> + +#define MVMDIO_SMI_DATA_SHIFT 0 +#define MVMDIO_SMI_PHY_ADDR_SHIFT 16 +#define MVMDIO_SMI_PHY_REG_SHIFT 21 +#define MVMDIO_SMI_READ_OPERATION BIT(26) +#define MVMDIO_SMI_WRITE_OPERATION 0 +#define MVMDIO_SMI_READ_VALID BIT(27) +#define MVMDIO_SMI_BUSY BIT(28) +#define MVMDIO_ERR_INT_CAUSE 0x007C +#define MVMDIO_ERR_INT_SMI_DONE 0x00000010 +#define MVMDIO_ERR_INT_MASK 0x0080 + +/* + * SMI Timeout measurements: + * - Kirkwood 88F6281 (Globalscale Dreamplug): 45us to 95us (Interrupt) + * - Armada 370 (Globalscale Mirabox): 41us to 43us (Polled) + */ +#define MVMDIO_SMI_TIMEOUT 1000 /* 1000us = 1ms */ +#define MVMDIO_SMI_POLL_INTERVAL_MIN 45 +#define MVMDIO_SMI_POLL_INTERVAL_MAX 55 + +struct orion_mdio_dev { + struct mutex lock; + void __iomem *regs; + struct clk *clk; + /* + * If we have access to the error interrupt pin (which is + * somewhat misnamed as it not only reflects internal errors + * but also reflects SMI completion), use that to wait for + * SMI access completion instead of polling the SMI busy bit. + */ + int err_interrupt; + wait_queue_head_t smi_busy_wait; +}; + +static int orion_mdio_smi_is_done(struct orion_mdio_dev *dev) +{ + return !(readl(dev->regs) & MVMDIO_SMI_BUSY); +} + +/* Wait for the SMI unit to be ready for another operation + */ +static int orion_mdio_wait_ready(struct mii_bus *bus) +{ + struct orion_mdio_dev *dev = bus->priv; + unsigned long timeout = usecs_to_jiffies(MVMDIO_SMI_TIMEOUT); + unsigned long end = jiffies + timeout; + int timedout = 0; + + while (1) { + if (orion_mdio_smi_is_done(dev)) + return 0; + else if (timedout) + break; + + if (dev->err_interrupt <= 0) { + usleep_range(MVMDIO_SMI_POLL_INTERVAL_MIN, + MVMDIO_SMI_POLL_INTERVAL_MAX); + + if (time_is_before_jiffies(end)) + ++timedout; + } else { + /* wait_event_timeout does not guarantee a delay of at + * least one whole jiffie, so timeout must be no less + * than two. + */ + if (timeout < 2) + timeout = 2; + wait_event_timeout(dev->smi_busy_wait, + orion_mdio_smi_is_done(dev), + timeout); + + ++timedout; + } + } + + dev_err(bus->parent, "Timeout: SMI busy for too long\n"); + return -ETIMEDOUT; +} + +static int orion_mdio_read(struct mii_bus *bus, int mii_id, + int regnum) +{ + struct orion_mdio_dev *dev = bus->priv; + u32 val; + int ret; + + mutex_lock(&dev->lock); + + ret = orion_mdio_wait_ready(bus); + if (ret < 0) + goto out; + + writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) | + (regnum << MVMDIO_SMI_PHY_REG_SHIFT) | + MVMDIO_SMI_READ_OPERATION), + dev->regs); + + ret = orion_mdio_wait_ready(bus); + if (ret < 0) + goto out; + + val = readl(dev->regs); + if (!(val & MVMDIO_SMI_READ_VALID)) { + dev_err(bus->parent, "SMI bus read not valid\n"); + ret = -ENODEV; + goto out; + } + + ret = val & 0xFFFF; +out: + mutex_unlock(&dev->lock); + return ret; +} + +static int orion_mdio_write(struct mii_bus *bus, int mii_id, + int regnum, u16 value) +{ + struct orion_mdio_dev *dev = bus->priv; + int ret; + + mutex_lock(&dev->lock); + + ret = orion_mdio_wait_ready(bus); + if (ret < 0) + goto out; + + writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) | + (regnum << MVMDIO_SMI_PHY_REG_SHIFT) | + MVMDIO_SMI_WRITE_OPERATION | + (value << MVMDIO_SMI_DATA_SHIFT)), + dev->regs); + +out: + mutex_unlock(&dev->lock); + return ret; +} + +static irqreturn_t orion_mdio_err_irq(int irq, void *dev_id) +{ + struct orion_mdio_dev *dev = dev_id; + + if (readl(dev->regs + MVMDIO_ERR_INT_CAUSE) & + MVMDIO_ERR_INT_SMI_DONE) { + writel(~MVMDIO_ERR_INT_SMI_DONE, + dev->regs + MVMDIO_ERR_INT_CAUSE); + wake_up(&dev->smi_busy_wait); + return IRQ_HANDLED; + } + + return IRQ_NONE; +} + +static int orion_mdio_probe(struct platform_device *pdev) +{ + struct resource *r; + struct mii_bus *bus; + struct orion_mdio_dev *dev; + int i, ret; + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!r) { + dev_err(&pdev->dev, "No SMI register address given\n"); + return -ENODEV; + } + + bus = devm_mdiobus_alloc_size(&pdev->dev, + sizeof(struct orion_mdio_dev)); + if (!bus) + return -ENOMEM; + + bus->name = "orion_mdio_bus"; + bus->read = orion_mdio_read; + bus->write = orion_mdio_write; + snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii", + dev_name(&pdev->dev)); + bus->parent = &pdev->dev; + + bus->irq = devm_kmalloc_array(&pdev->dev, PHY_MAX_ADDR, sizeof(int), + GFP_KERNEL); + if (!bus->irq) + return -ENOMEM; + + for (i = 0; i < PHY_MAX_ADDR; i++) + bus->irq[i] = PHY_POLL; + + dev = bus->priv; + dev->regs = devm_ioremap(&pdev->dev, r->start, resource_size(r)); + if (!dev->regs) { + dev_err(&pdev->dev, "Unable to remap SMI register\n"); + ret = -ENODEV; + goto out_mdio; + } + + init_waitqueue_head(&dev->smi_busy_wait); + + dev->clk = devm_clk_get(&pdev->dev, NULL); + if (!IS_ERR(dev->clk)) + clk_prepare_enable(dev->clk); + + dev->err_interrupt = platform_get_irq(pdev, 0); + if (dev->err_interrupt > 0) { + ret = devm_request_irq(&pdev->dev, dev->err_interrupt, + orion_mdio_err_irq, + IRQF_SHARED, pdev->name, dev); + if (ret) + goto out_mdio; + + writel(MVMDIO_ERR_INT_SMI_DONE, + dev->regs + MVMDIO_ERR_INT_MASK); + + } else if (dev->err_interrupt == -EPROBE_DEFER) { + return -EPROBE_DEFER; + } + + mutex_init(&dev->lock); + + if (pdev->dev.of_node) + ret = of_mdiobus_register(bus, pdev->dev.of_node); + else + ret = mdiobus_register(bus); + if (ret < 0) { + dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret); + goto out_mdio; + } + + platform_set_drvdata(pdev, bus); + + return 0; + +out_mdio: + if (!IS_ERR(dev->clk)) + clk_disable_unprepare(dev->clk); + return ret; +} + +static int orion_mdio_remove(struct platform_device *pdev) +{ + struct mii_bus *bus = platform_get_drvdata(pdev); + struct orion_mdio_dev *dev = bus->priv; + + writel(0, dev->regs + MVMDIO_ERR_INT_MASK); + mdiobus_unregister(bus); + if (!IS_ERR(dev->clk)) + clk_disable_unprepare(dev->clk); + + return 0; +} + +static const struct of_device_id orion_mdio_match[] = { + { .compatible = "marvell,orion-mdio" }, + { } +}; +MODULE_DEVICE_TABLE(of, orion_mdio_match); + +static struct platform_driver orion_mdio_driver = { + .probe = orion_mdio_probe, + .remove = orion_mdio_remove, + .driver = { + .name = "orion-mdio", + .of_match_table = orion_mdio_match, + }, +}; + +module_platform_driver(orion_mdio_driver); + +MODULE_DESCRIPTION("Marvell MDIO interface driver"); +MODULE_AUTHOR("Thomas Petazzoni <thomas.petazzoni@free-electrons.com>"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:orion-mdio"); |