[PATCH 1/1] uio: uio_fsl_elbc_gpcm: new driver

[John Ogness]

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@xxxxxxxxxxxxx>
---
There are currently drivers that use FCM and UPM modes. But there
are no drivers using the very simple GPCM mode. If other drivers
from other subsystems should start using this mode (for example,
mtd, eeprom, char) then it may make sense to try to implement
generic GPCM support in arch/powerpc/sysdev/fsl_lbc.c. There
would not be much overlap, but there is no point in having
multiple drivers implement bank and OR/BR validation.

As for the device-specific netX support, I considered if a common
header file with the PCI variant drivers/uio/uio_netx.c should
exist. Merging the two drivers didn't seem to make sense since
this is actually a generic eLBC-GPCM driver (that optionally
supports netX) and the other is a PCI netX driver.

 .../devicetree/bindings/powerpc/fsl/lbc.txt        |   18 +-
 arch/powerpc/include/asm/fsl_lbc.h                 |    3 +
 drivers/uio/Kconfig                                |   20 +
 drivers/uio/Makefile                               |    1 +
 drivers/uio/uio_fsl_elbc_gpcm.c                    |  499 ++++++++++++++++++++
 5 files changed, 536 insertions(+), 5 deletions(-)
 create mode 100644 drivers/uio/uio_fsl_elbc_gpcm.c

diff --git a/Documentation/devicetree/bindings/powerpc/fsl/lbc.txt b/Documentation/devicetree/bindings/powerpc/fsl/lbc.txt
index 3300fec..1c80fce 100644
--- a/Documentation/devicetree/bindings/powerpc/fsl/lbc.txt
+++ b/Documentation/devicetree/bindings/powerpc/fsl/lbc.txt
@@ -16,20 +16,28 @@ Example:
 			   "fsl,pq2-localbus";
 		#address-cells = <2>;
 		#size-cells = <1>;
-		reg = <f0010100 40>;
+		reg = <0xf0010100 0x40>;
 
-		ranges = <0 0 fe000000 02000000
-			  1 0 f4500000 00008000>;
+		ranges = <0x0 0x0 0xfe000000 0x02000000
+			  0x1 0x0 0xf4500000 0x00008000
+			  0x2 0x0 0xfd810000 0x00010000>;
 
 		flash@0,0 {
 			compatible = "jedec-flash";
-			reg = <0 0 2000000>;
+			reg = <0x0 0x0 0x2000000>;
 			bank-width = <4>;
 			device-width = <1>;
 		};
 
 		board-control@1,0 {
-			reg = <1 0 20>;
+			reg = <0x1 0x0 0x20>;
 			compatible = "fsl,mpc8272ads-bcsr";
 		};
+
+		simple-periph@2,0 {
+			compatible = "fsl,elbc-gpcm-uio";
+			reg = <0x2 0x0 0x10000>;
+			elbc-gpcm-br = <0xfd810800>;
+			elbc-gpcm-or = <0xffff09f7>;
+		};
 	};
diff --git a/arch/powerpc/include/asm/fsl_lbc.h b/arch/powerpc/include/asm/fsl_lbc.h
index 067fb0d..c7240a0 100644
--- a/arch/powerpc/include/asm/fsl_lbc.h
+++ b/arch/powerpc/include/asm/fsl_lbc.h
@@ -95,6 +95,9 @@ struct fsl_lbc_bank {
 #define OR_FCM_TRLX_SHIFT                2
 #define OR_FCM_EHTR             0x00000002
 #define OR_FCM_EHTR_SHIFT                1
+
+#define OR_GPCM_AM		0xFFFF8000
+#define OR_GPCM_AM_SHIFT		15
 };
 
 struct fsl_lbc_regs {
diff --git a/drivers/uio/Kconfig b/drivers/uio/Kconfig
index 5a90914..8a15c32 100644
--- a/drivers/uio/Kconfig
+++ b/drivers/uio/Kconfig
@@ -104,6 +104,26 @@ config UIO_NETX
 	  To compile this driver as a module, choose M here; the module
 	  will be called uio_netx.
 
+config UIO_FSL_ELBC_GPCM
+	tristate "eLBC/GPCM driver"
+	depends on FSL_LBC
+	help
+	  Generic driver for accessing a peripheral connected to an eLBC port
+	  that is running in GPCM mode. GPCM is an interface for simple lower
+	  performance memories and memory-mapped devices. For devices using
+	  FCM or UPM eLBC modes, other device-specific drivers are available.
+
+config UIO_FSL_ELBC_GPCM_NETX5152
+	bool "eLBC/GPCM netX 51/52 support"
+	depends on UIO_FSL_ELBC_GPCM
+	help
+	  This will add support for netX 51/52 devices connected via eLBC/GPCM.
+	  In particular, it implements interrupt handling. This can be used
+	  together with the userspace netX stack from Hilscher.
+
+	  Information about this hardware can be found at:
+	  http://www.hilscher.com/netx
+
 config UIO_PRUSS
 	tristate "Texas Instruments PRUSS driver"
 	depends on ARCH_DAVINCI_DA850
diff --git a/drivers/uio/Makefile b/drivers/uio/Makefile
index d3218bd..8560dad 100644
--- a/drivers/uio/Makefile
+++ b/drivers/uio/Makefile
@@ -8,3 +8,4 @@ obj-$(CONFIG_UIO_PCI_GENERIC)	+= uio_pci_generic.o
 obj-$(CONFIG_UIO_NETX)	+= uio_netx.o
 obj-$(CONFIG_UIO_PRUSS)         += uio_pruss.o
 obj-$(CONFIG_UIO_MF624)         += uio_mf624.o
+obj-$(CONFIG_UIO_FSL_ELBC_GPCM)	+= uio_fsl_elbc_gpcm.o
diff --git a/drivers/uio/uio_fsl_elbc_gpcm.c b/drivers/uio/uio_fsl_elbc_gpcm.c
new file mode 100644
index 0000000..b6cac91
--- /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@xxxxxxxxxxxxx>
+
+   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@xxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Freescale Enhanced Local Bus Controller GPCM driver");
-- 
1.7.10.4
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