uio: uio_fsl_elbc_gpcm: new driver

This driver provides UIO access to memory of a peripheral connected
to the Freescale enhanced local bus controller (eLBC) interface
using the general purpose chip-select mode (GPCM).

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 499 insertions, 0 deletions

diff --git a/drivers/uio/uio_fsl_elbc_gpcm.c b/drivers/uio/uio_fsl_elbc_gpcm.c
new file mode 100644
index 000000000000..b6cac91c2ced
--- /dev/null
+++ b/drivers/uio/uio_fsl_elbc_gpcm.c
@@ -0,0 +1,499 @@
+/* uio_fsl_elbc_gpcm: UIO driver for eLBC/GPCM peripherals
+
+   Copyright (C) 2014 Linutronix GmbH
+     Author: John Ogness <john.ogness@linutronix.de>
+
+   This driver provides UIO access to memory of a peripheral connected
+   to the Freescale enhanced local bus controller (eLBC) interface
+   using the general purpose chip-select mode (GPCM).
+
+   Here is an example of the device tree entries:
+
+	localbus@ffe05000 {
+		ranges = <0x2 0x0 0x0 0xff810000 0x10000>;
+
+		dpm@2,0 {
+			compatible = "fsl,elbc-gpcm-uio";
+			reg = <0x2 0x0 0x10000>;
+			elbc-gpcm-br = <0xff810800>;
+			elbc-gpcm-or = <0xffff09f7>;
+			interrupt-parent = <&mpic>;
+			interrupts = <4 1>;
+			device_type = "netx5152";
+			uio_name = "netx_custom";
+			netx5152,init-win0-offset = <0x0>;
+		};
+	};
+
+   Only the entries reg (to identify bank) and elbc-gpcm-* (initial BR/OR
+   values) are required. The entries interrupt*, device_type, and uio_name
+   are optional (as well as any type-specific options such as
+   netx5152,init-win0-offset). As long as no interrupt handler is needed,
+   this driver can be used without any type-specific implementation.
+
+   The netx5152 type has been tested to work with the netX 51/52 hardware
+   from Hilscher using the Hilscher userspace netX stack.
+
+   The netx5152 type should serve as a model to add new type-specific
+   devices as needed.
+*/
+
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/uio_driver.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#include <asm/fsl_lbc.h>
+
+#define MAX_BANKS 8
+
+struct fsl_elbc_gpcm {
+	struct device *dev;
+	struct fsl_lbc_regs __iomem *lbc;
+	u32 bank;
+	const char *name;
+
+	void (*init)(struct uio_info *info);
+	void (*shutdown)(struct uio_info *info, bool init_err);
+	irqreturn_t (*irq_handler)(int irq, struct uio_info *info);
+};
+
+static ssize_t reg_show(struct device *dev, struct device_attribute *attr,
+			char *buf);
+static ssize_t reg_store(struct device *dev, struct device_attribute *attr,
+			 const char *buf, size_t count);
+
+DEVICE_ATTR(reg_br, S_IRUGO|S_IWUSR|S_IWGRP, reg_show, reg_store);
+DEVICE_ATTR(reg_or, S_IRUGO|S_IWUSR|S_IWGRP, reg_show, reg_store);
+
+static ssize_t reg_show(struct device *dev, struct device_attribute *attr,
+			char *buf)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct uio_info *info = platform_get_drvdata(pdev);
+	struct fsl_elbc_gpcm *priv = info->priv;
+	struct fsl_lbc_bank *bank = &priv->lbc->bank[priv->bank];
+
+	if (attr == &dev_attr_reg_br) {
+		return scnprintf(buf, PAGE_SIZE, "0x%08x\n",
+				 in_be32(&bank->br));
+
+	} else if (attr == &dev_attr_reg_or) {
+		return scnprintf(buf, PAGE_SIZE, "0x%08x\n",
+				 in_be32(&bank->or));
+	}
+
+	return 0;
+}
+
+static ssize_t reg_store(struct device *dev, struct device_attribute *attr,
+			 const char *buf, size_t count)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct uio_info *info = platform_get_drvdata(pdev);
+	struct fsl_elbc_gpcm *priv = info->priv;
+	struct fsl_lbc_bank *bank = &priv->lbc->bank[priv->bank];
+	unsigned long val;
+	u32 reg_br_cur;
+	u32 reg_or_cur;
+	u32 reg_new;
+
+	/* parse use input */
+	if (kstrtoul(buf, 0, &val) != 0)
+		return -EINVAL;
+	reg_new = (u32)val;
+
+	/* read current values */
+	reg_br_cur = in_be32(&bank->br);
+	reg_or_cur = in_be32(&bank->or);
+
+	if (attr == &dev_attr_reg_br) {
+		/* not allowed to change effective base address */
+		if ((reg_br_cur & reg_or_cur & BR_BA) !=
+		    (reg_new & reg_or_cur & BR_BA)) {
+			return -EINVAL;
+		}
+
+		/* not allowed to change mode */
+		if ((reg_new & BR_MSEL) != BR_MS_GPCM)
+			return -EINVAL;
+
+		/* write new value (force valid) */
+		out_be32(&bank->br, reg_new | BR_V);
+
+	} else if (attr == &dev_attr_reg_or) {
+		/* not allowed to change access mask */
+		if ((reg_or_cur & OR_GPCM_AM) != (reg_new & OR_GPCM_AM))
+			return -EINVAL;
+
+		/* write new value */
+		out_be32(&bank->or, reg_new);
+
+	} else {
+		return -EINVAL;
+	}
+
+	return count;
+}
+
+#ifdef CONFIG_UIO_FSL_ELBC_GPCM_NETX5152
+#define DPM_HOST_WIN0_OFFSET	0xff00
+#define DPM_HOST_INT_STAT0	0xe0
+#define DPM_HOST_INT_EN0	0xf0
+#define DPM_HOST_INT_MASK	0xe600ffff
+#define DPM_HOST_INT_GLOBAL_EN	0x80000000
+
+static irqreturn_t netx5152_irq_handler(int irq, struct uio_info *info)
+{
+	void __iomem *reg_int_en = info->mem[0].internal_addr +
+					DPM_HOST_WIN0_OFFSET +
+					DPM_HOST_INT_EN0;
+	void __iomem *reg_int_stat = info->mem[0].internal_addr +
+					DPM_HOST_WIN0_OFFSET +
+					DPM_HOST_INT_STAT0;
+
+	/* check if an interrupt is enabled and active */
+	if ((ioread32(reg_int_en) & ioread32(reg_int_stat) &
+	     DPM_HOST_INT_MASK) == 0) {
+		return IRQ_NONE;
+	}
+
+	/* disable interrupts */
+	iowrite32(ioread32(reg_int_en) & ~DPM_HOST_INT_GLOBAL_EN, reg_int_en);
+
+	return IRQ_HANDLED;
+}
+
+static void netx5152_init(struct uio_info *info)
+{
+	unsigned long win0_offset = DPM_HOST_WIN0_OFFSET;
+	struct fsl_elbc_gpcm *priv = info->priv;
+	const void *prop;
+
+	/* get an optional initial win0 offset */
+	prop = of_get_property(priv->dev->of_node,
+			       "netx5152,init-win0-offset", NULL);
+	if (prop)
+		win0_offset = of_read_ulong(prop, 1);
+
+	/* disable interrupts */
+	iowrite32(0, info->mem[0].internal_addr + win0_offset +
+		     DPM_HOST_INT_EN0);
+}
+
+static void netx5152_shutdown(struct uio_info *info, bool init_err)
+{
+	if (init_err)
+		return;
+
+	/* disable interrupts */
+	iowrite32(0, info->mem[0].internal_addr + DPM_HOST_WIN0_OFFSET +
+		     DPM_HOST_INT_EN0);
+}
+#endif
+
+static void setup_periph(struct fsl_elbc_gpcm *priv,
+				   const char *type)
+{
+#ifdef CONFIG_UIO_FSL_ELBC_GPCM_NETX5152
+	if (strcmp(type, "netx5152") == 0) {
+		priv->irq_handler = netx5152_irq_handler;
+		priv->init = netx5152_init;
+		priv->shutdown = netx5152_shutdown;
+		priv->name = "netX 51/52";
+		return;
+	}
+#endif
+}
+
+static int check_of_data(struct fsl_elbc_gpcm *priv,
+				   struct resource *res,
+				   u32 reg_br, u32 reg_or)
+{
+	/* check specified bank */
+	if (priv->bank >= MAX_BANKS) {
+		dev_err(priv->dev, "invalid bank\n");
+		return -ENODEV;
+	}
+
+	/* check specified mode (BR_MS_GPCM is 0) */
+	if ((reg_br & BR_MSEL) != BR_MS_GPCM) {
+		dev_err(priv->dev, "unsupported mode\n");
+		return -ENODEV;
+	}
+
+	/* check specified mask vs. resource size */
+	if ((~(reg_or & OR_GPCM_AM) + 1) != resource_size(res)) {
+		dev_err(priv->dev, "address mask / size mismatch\n");
+		return -ENODEV;
+	}
+
+	/* check specified address */
+	if ((reg_br & reg_or & BR_BA) != fsl_lbc_addr(res->start)) {
+		dev_err(priv->dev, "base address mismatch\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int get_of_data(struct fsl_elbc_gpcm *priv, struct device_node *node,
+		       struct resource *res, u32 *reg_br,
+		       u32 *reg_or, unsigned int *irq, char **name)
+{
+	const char *dt_name;
+	const char *type;
+	int ret;
+
+	/* get the memory resource */
+	ret = of_address_to_resource(node, 0, res);
+	if (ret) {
+		dev_err(priv->dev, "failed to get resource\n");
+		return ret;
+	}
+
+	/* get the bank number */
+	ret = of_property_read_u32(node, "reg", &priv->bank);
+	if (ret) {
+		dev_err(priv->dev, "failed to get bank number\n");
+		return ret;
+	}
+
+	/* get BR value to set */
+	ret = of_property_read_u32(node, "elbc-gpcm-br", reg_br);
+	if (ret) {
+		dev_err(priv->dev, "missing elbc-gpcm-br value\n");
+		return ret;
+	}
+
+	/* get OR value to set */
+	ret = of_property_read_u32(node, "elbc-gpcm-or", reg_or);
+	if (ret) {
+		dev_err(priv->dev, "missing elbc-gpcm-or value\n");
+		return ret;
+	}
+
+	/* get optional peripheral type */
+	priv->name = "generic";
+	if (of_property_read_string(node, "device_type", &type) == 0)
+		setup_periph(priv, type);
+
+	/* get optional irq value */
+	*irq = irq_of_parse_and_map(node, 0);
+
+	/* sanity check device tree data */
+	ret = check_of_data(priv, res, *reg_br, *reg_or);
+	if (ret)
+		return ret;
+
+	/* get optional uio name */
+	if (of_property_read_string(node, "uio_name", &dt_name) != 0)
+		dt_name = "eLBC_GPCM";
+	*name = kstrdup(dt_name, GFP_KERNEL);
+	if (!*name)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static int uio_fsl_elbc_gpcm_probe(struct platform_device *pdev)
+{
+	struct device_node *node = pdev->dev.of_node;
+	struct fsl_elbc_gpcm *priv;
+	struct uio_info *info;
+	char *uio_name = NULL;
+	struct resource res;
+	unsigned int irq;
+	u32 reg_br_cur;
+	u32 reg_or_cur;
+	u32 reg_br_new;
+	u32 reg_or_new;
+	int ret;
+
+	if (!fsl_lbc_ctrl_dev || !fsl_lbc_ctrl_dev->regs)
+		return -ENODEV;
+
+	/* allocate private data */
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+	priv->dev = &pdev->dev;
+	priv->lbc = fsl_lbc_ctrl_dev->regs;
+
+	/* get device tree data */
+	ret = get_of_data(priv, node, &res, &reg_br_new, &reg_or_new,
+			  &irq, &uio_name);
+	if (ret)
+		goto out_err0;
+
+	/* allocate UIO structure */
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info) {
+		ret = -ENOMEM;
+		goto out_err0;
+	}
+
+	/* get current BR/OR values */
+	reg_br_cur = in_be32(&priv->lbc->bank[priv->bank].br);
+	reg_or_cur = in_be32(&priv->lbc->bank[priv->bank].or);
+
+	/* if bank already configured, make sure it matches */
+	if ((reg_br_cur & BR_V)) {
+		if ((reg_br_cur & BR_MSEL) != BR_MS_GPCM ||
+		    (reg_br_cur & reg_or_cur & BR_BA)
+		     != fsl_lbc_addr(res.start)) {
+			dev_err(priv->dev,
+				"bank in use by another peripheral\n");
+			ret = -ENODEV;
+			goto out_err1;
+		}
+
+		/* warn if behavior settings changing */
+		if ((reg_br_cur & ~(BR_BA | BR_V)) !=
+		    (reg_br_new & ~(BR_BA | BR_V))) {
+			dev_warn(priv->dev,
+				 "modifying BR settings: 0x%08x -> 0x%08x",
+				 reg_br_cur, reg_br_new);
+		}
+		if ((reg_or_cur & ~OR_GPCM_AM) != (reg_or_new & ~OR_GPCM_AM)) {
+			dev_warn(priv->dev,
+				 "modifying OR settings: 0x%08x -> 0x%08x",
+				 reg_or_cur, reg_or_new);
+		}
+	}
+
+	/* configure the bank (force base address and GPCM) */
+	reg_br_new &= ~(BR_BA | BR_MSEL);
+	reg_br_new |= fsl_lbc_addr(res.start) | BR_MS_GPCM | BR_V;
+	out_be32(&priv->lbc->bank[priv->bank].or, reg_or_new);
+	out_be32(&priv->lbc->bank[priv->bank].br, reg_br_new);
+
+	/* map the memory resource */
+	info->mem[0].internal_addr = ioremap(res.start, resource_size(&res));
+	if (!info->mem[0].internal_addr) {
+		dev_err(priv->dev, "failed to map chip region\n");
+		ret = -ENODEV;
+		goto out_err1;
+	}
+
+	/* set all UIO data */
+	if (node->name)
+		info->mem[0].name = kstrdup(node->name, GFP_KERNEL);
+	info->mem[0].addr = res.start;
+	info->mem[0].size = resource_size(&res);
+	info->mem[0].memtype = UIO_MEM_PHYS;
+	info->priv = priv;
+	info->name = uio_name;
+	info->version = "0.0.1";
+	if (irq != NO_IRQ) {
+		if (priv->irq_handler) {
+			info->irq = irq;
+			info->irq_flags = IRQF_SHARED;
+			info->handler = priv->irq_handler;
+		} else {
+			irq = NO_IRQ;
+			dev_warn(priv->dev, "ignoring irq, no handler\n");
+		}
+	}
+
+	if (priv->init)
+		priv->init(info);
+
+	/* register UIO device */
+	if (uio_register_device(priv->dev, info) != 0) {
+		dev_err(priv->dev, "UIO registration failed\n");
+		ret = -ENODEV;
+		goto out_err2;
+	}
+
+	/* store private data */
+	platform_set_drvdata(pdev, info);
+
+	/* create sysfs files */
+	ret = device_create_file(priv->dev, &dev_attr_reg_br);
+	if (ret)
+		goto out_err3;
+	ret = device_create_file(priv->dev, &dev_attr_reg_or);
+	if (ret)
+		goto out_err4;
+
+	dev_info(priv->dev,
+		 "eLBC/GPCM device (%s) at 0x%llx, bank %d, irq=%d\n",
+		 priv->name, (unsigned long long)res.start, priv->bank,
+		 irq != NO_IRQ ? irq : -1);
+
+	return 0;
+out_err4:
+	device_remove_file(priv->dev, &dev_attr_reg_br);
+out_err3:
+	platform_set_drvdata(pdev, NULL);
+	uio_unregister_device(info);
+out_err2:
+	if (priv->shutdown)
+		priv->shutdown(info, true);
+	iounmap(info->mem[0].internal_addr);
+out_err1:
+	kfree(info->mem[0].name);
+	kfree(info);
+out_err0:
+	kfree(uio_name);
+	kfree(priv);
+	return ret;
+}
+
+static int uio_fsl_elbc_gpcm_remove(struct platform_device *pdev)
+{
+	struct uio_info *info = platform_get_drvdata(pdev);
+	struct fsl_elbc_gpcm *priv = info->priv;
+
+	device_remove_file(priv->dev, &dev_attr_reg_or);
+	device_remove_file(priv->dev, &dev_attr_reg_br);
+	platform_set_drvdata(pdev, NULL);
+	uio_unregister_device(info);
+	if (priv->shutdown)
+		priv->shutdown(info, false);
+	iounmap(info->mem[0].internal_addr);
+	kfree(info->mem[0].name);
+	kfree(info->name);
+	kfree(info);
+	kfree(priv);
+
+	return 0;
+
+}
+
+static const struct of_device_id uio_fsl_elbc_gpcm_match[] = {
+	{ .compatible = "fsl,elbc-gpcm-uio", },
+	{}
+};
+
+static struct platform_driver uio_fsl_elbc_gpcm_driver = {
+	.driver = {
+		.name = "fsl,elbc-gpcm-uio",
+		.owner = THIS_MODULE,
+		.of_match_table = uio_fsl_elbc_gpcm_match,
+	},
+	.probe = uio_fsl_elbc_gpcm_probe,
+	.remove = uio_fsl_elbc_gpcm_remove,
+};
+
+static int __init uio_fsl_elbc_gpcm_init(void)
+{
+	return platform_driver_register(&uio_fsl_elbc_gpcm_driver);
+}
+
+static void __exit uio_fsl_elbc_gpcm_exit(void)
+{
+	platform_driver_unregister(&uio_fsl_elbc_gpcm_driver);
+}
+
+module_init(uio_fsl_elbc_gpcm_init);
+module_exit(uio_fsl_elbc_gpcm_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("John Ogness <john.ogness@linutronix.de>");
+MODULE_DESCRIPTION("Freescale Enhanced Local Bus Controller GPCM driver");