[PATCH 1/3] Introduce ARM AMBA bus
Jean-Christophe PLAGNIOL-VILLARD
plagnioj at jcrosoft.com
Sat Sep 1 08:36:28 EDT 2012
This will allow to detect the amba device and use the right driver for it at
runtime.
The code is base on linux 3.5.
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
---
drivers/Makefile | 1 +
drivers/amba/Makefile | 2 +
drivers/amba/bus.c | 212 ++++++++++++++++++++++++++++++++++++++++++++++
include/linux/amba/bus.h | 157 ++++++++++++++++++++++++++++++++++
4 files changed, 372 insertions(+)
create mode 100644 drivers/amba/Makefile
create mode 100644 drivers/amba/bus.c
create mode 100644 include/linux/amba/bus.h
diff --git a/drivers/Makefile b/drivers/Makefile
index 005ab24..ceb8f82 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -1,4 +1,5 @@
obj-y += base/
+obj-$(CONFIG_ARM_AMBA) += amba/
obj-y += net/
obj-y += serial/
obj-y += mtd/
diff --git a/drivers/amba/Makefile b/drivers/amba/Makefile
new file mode 100644
index 0000000..a4a511b
--- /dev/null
+++ b/drivers/amba/Makefile
@@ -0,0 +1,2 @@
+
+obj-y += bus.o
diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
new file mode 100644
index 0000000..6cde349
--- /dev/null
+++ b/drivers/amba/bus.c
@@ -0,0 +1,212 @@
+/*
+ * Copyright (C) 2003 Deep Blue Solutions Ltd, All Rights Reserved.
+ * Copyright (c) 2012 Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
+ *
+ * Under GPLv2.
+ */
+#include <common.h>
+#include <driver.h>
+#include <linux/clk.h>
+#include <linux/amba/bus.h>
+#include <io.h>
+
+#define to_amba_driver(d) container_of(d, struct amba_driver, drv)
+
+static const struct amba_id *
+amba_lookup(const struct amba_id *table, struct amba_device *dev)
+{
+ int ret = 0;
+
+ while (table->mask) {
+ ret = (dev->periphid & table->mask) == table->id;
+ if (ret)
+ break;
+ table++;
+ }
+
+ return ret ? table : NULL;
+}
+
+static int amba_match(struct device_d *dev, struct driver_d *drv)
+{
+ struct amba_device *pcdev = to_amba_device(dev);
+
+ struct amba_driver *pcdrv = to_amba_driver(drv);
+
+ return amba_lookup(pcdrv->id_table, pcdev) == NULL;
+}
+
+static int amba_get_enable_pclk(struct amba_device *pcdev)
+{
+ struct clk *pclk = clk_get(&pcdev->dev, "apb_pclk");
+ int ret;
+
+ pcdev->pclk = pclk;
+
+ if (IS_ERR(pclk))
+ return PTR_ERR(pclk);
+
+ ret = clk_enable(pclk);
+ if (ret) {
+ clk_put(pclk);
+ }
+
+ return ret;
+}
+
+static int amba_probe(struct device_d *dev)
+{
+ struct amba_device *pcdev = to_amba_device(dev);
+ struct amba_driver *pcdrv = to_amba_driver(dev->driver);
+ const struct amba_id *id = amba_lookup(pcdrv->id_table, pcdev);
+
+ return pcdrv->probe(pcdev, id);
+}
+
+static void amba_remove(struct device_d *dev)
+{
+ struct amba_device *pcdev = to_amba_device(dev);
+ struct amba_driver *drv = to_amba_driver(dev->driver);
+
+ drv->remove(pcdev);
+}
+
+struct bus_type amba_bustype = {
+ .name = "amba",
+ .match = amba_match,
+ .probe = amba_probe,
+ .remove = amba_remove,
+};
+
+int amba_driver_register(struct amba_driver *drv)
+{
+ drv->drv.bus = &amba_bustype;
+#define SETFN(fn) if (drv->fn) drv->drv.fn = amba_##fn
+ SETFN(probe);
+ SETFN(remove);
+
+ return register_driver(&drv->drv);
+}
+
+/**
+ * amba_device_add - add a previously allocated AMBA device structure
+ * @dev: AMBA device allocated by amba_device_alloc
+ * @parent: resource parent for this devices resources
+ *
+ * Claim the resource, and read the device cell ID if not already
+ * initialized. Register the AMBA device with the Linux device
+ * manager.
+ */
+int amba_device_add(struct amba_device *dev)
+{
+ u32 size;
+ void __iomem *tmp;
+ int i, ret;
+ struct resource *res = NULL;
+
+ dev->dev.bus = &amba_bustype;
+
+ /*
+ * Dynamically calculate the size of the resource
+ * and use this for iomap
+ */
+ size = resource_size(&dev->res);
+ res = request_iomem_region("amba", dev->res.start, dev->res.end);
+ if (!res)
+ return -ENOMEM;
+ dev->base = tmp = (void __force __iomem *)res->start;
+ if (!tmp) {
+ ret = -ENOMEM;
+ goto err_release;
+ }
+
+ /* Hard-coded primecell ID instead of plug-n-play */
+ if (dev->periphid != 0)
+ goto skip_probe;
+
+ ret = amba_get_enable_pclk(dev);
+ if (ret == 0) {
+ u32 pid, cid;
+
+ /*
+ * Read pid and cid based on size of resource
+ * they are located at end of region
+ */
+ for (pid = 0, i = 0; i < 4; i++)
+ pid |= (readl(tmp + size - 0x20 + 4 * i) & 255) <<
+ (i * 8);
+ for (cid = 0, i = 0; i < 4; i++)
+ cid |= (readl(tmp + size - 0x10 + 4 * i) & 255) <<
+ (i * 8);
+
+ if (cid == AMBA_CID)
+ dev->periphid = pid;
+
+ if (!dev->periphid)
+ ret = -ENODEV;
+ }
+
+ if (ret)
+ goto err_release;
+
+ skip_probe:
+ ret = register_device(&dev->dev);
+ if (ret)
+ goto err_release;
+
+ return ret;
+ err_release:
+ release_region(res);
+ return ret;
+}
+
+struct amba_device *
+amba_aphb_device_add(struct device_d *parent, const char *name, int id,
+ resource_size_t base, size_t size,
+ void *pdata, unsigned int periphid)
+{
+ struct amba_device *dev;
+ int ret;
+
+ dev = amba_device_alloc(name, id, base, size);
+ if (!dev)
+ return ERR_PTR(-ENOMEM);
+
+ dev->periphid = periphid;
+ dev->dev.platform_data = pdata;
+ dev->dev.parent = parent;
+
+ ret = amba_device_add(dev);
+ if (ret) {
+ return ERR_PTR(ret);
+ }
+
+ return dev;
+}
+
+/**
+ * amba_device_alloc - allocate an AMBA device
+ * @name: sysfs name of the AMBA device
+ * @base: base of AMBA device
+ * @size: size of AMBA device
+ *
+ * Allocate and initialize an AMBA device structure. Returns %NULL
+ * on failure.
+ */
+struct amba_device *amba_device_alloc(const char *name, int id, resource_size_t base,
+ size_t size)
+{
+ struct amba_device *dev;
+
+ dev = xzalloc(sizeof(*dev));
+ if (dev) {
+ strcpy(dev->dev.name, name);
+ dev->dev.id = id;
+ dev->res.start = base;
+ dev->res.end = base + size - 1;
+ dev->res.flags = IORESOURCE_MEM;
+ }
+
+ return dev;
+}
+
diff --git a/include/linux/amba/bus.h b/include/linux/amba/bus.h
new file mode 100644
index 0000000..34e6ace
--- /dev/null
+++ b/include/linux/amba/bus.h
@@ -0,0 +1,157 @@
+/*
+ * linux/include/amba/bus.h
+ *
+ * This device type deals with ARM PrimeCells and anything else that
+ * presents a proper CID (0xB105F00D) at the end of the I/O register
+ * region or that is derived from a PrimeCell.
+ *
+ * Copyright (C) 2003 Deep Blue Solutions Ltd, All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef ASMARM_AMBA_H
+#define ASMARM_AMBA_H
+
+#include <linux/clk.h>
+#include <driver.h>
+#include <linux/err.h>
+
+#define AMBA_CID 0xb105f00d
+
+/**
+ * struct amba_id - identifies a device on an AMBA bus
+ * @id: The significant bits if the hardware device ID
+ * @mask: Bitmask specifying which bits of the id field are significant when
+ * matching. A driver binds to a device when ((hardware device ID) & mask)
+ * == id.
+ * @data: Private data used by the driver.
+ */
+struct amba_id {
+ unsigned int id;
+ unsigned int mask;
+#ifndef __KERNEL__
+ kernel_ulong_t data;
+#else
+ void *data;
+#endif
+};
+
+struct clk;
+
+struct amba_device {
+ struct device_d dev;
+ struct resource res;
+ void __iomem *base;
+ struct clk *pclk;
+ unsigned int periphid;
+};
+
+struct amba_driver {
+ struct driver_d drv;
+ int (*probe)(struct amba_device *, const struct amba_id *);
+ int (*remove)(struct amba_device *);
+ const struct amba_id *id_table;
+};
+
+enum amba_vendor {
+ AMBA_VENDOR_ARM = 0x41,
+ AMBA_VENDOR_ST = 0x80,
+};
+
+extern struct bus_type amba_bustype;
+
+#define to_amba_device(d) container_of(d, struct amba_device, dev)
+
+#define amba_get_drvdata(d) dev_get_drvdata(&d->dev)
+#define amba_set_drvdata(d,p) dev_set_drvdata(&d->dev, p)
+
+int amba_driver_register(struct amba_driver *);
+void amba_driver_unregister(struct amba_driver *);
+struct amba_device *amba_device_alloc(const char *, int id, resource_size_t, size_t);
+void amba_device_put(struct amba_device *);
+int amba_device_add(struct amba_device *);
+int amba_device_register(struct amba_device *, struct resource *);
+
+struct amba_device *
+amba_aphb_device_add(struct device_d *parent, const char *name, int id,
+ resource_size_t base, size_t size,
+ void *pdata, unsigned int periphid);
+
+static inline struct amba_device *
+amba_apb_device_add(struct device_d *parent, const char *name, int id,
+ resource_size_t base, size_t size,
+ void *pdata, unsigned int periphid)
+{
+ return amba_aphb_device_add(parent, name, id, base, size, pdata,
+ periphid);
+}
+
+static inline struct amba_device *
+amba_ahb_device_add(struct device_d *parent, const char *name, int id,
+ resource_size_t base, size_t size,
+ void *pdata, unsigned int periphid)
+{
+ return amba_aphb_device_add(parent, name, id, base, size, pdata,
+ periphid);
+}
+
+
+void amba_device_unregister(struct amba_device *);
+struct amba_device *amba_find_device(const char *, struct device_d *, unsigned int, unsigned int);
+int amba_request_regions(struct amba_device *, const char *);
+void amba_release_regions(struct amba_device *);
+
+static inline void __iomem *amba_get_mem_region(struct amba_device *dev)
+{
+ return dev->base;
+}
+
+#define amba_pclk_enable(d) \
+ (IS_ERR((d)->pclk) ? 0 : clk_enable((d)->pclk))
+
+#define amba_pclk_disable(d) \
+ do { if (!IS_ERR((d)->pclk)) clk_disable((d)->pclk); } while (0)
+
+/* Some drivers don't use the struct amba_device */
+#define AMBA_CONFIG_BITS(a) (((a) >> 24) & 0xff)
+#define AMBA_REV_BITS(a) (((a) >> 20) & 0x0f)
+#define AMBA_MANF_BITS(a) (((a) >> 12) & 0xff)
+#define AMBA_PART_BITS(a) ((a) & 0xfff)
+
+#define amba_config(d) AMBA_CONFIG_BITS((d)->periphid)
+#define amba_rev(d) AMBA_REV_BITS((d)->periphid)
+#define amba_manf(d) AMBA_MANF_BITS((d)->periphid)
+#define amba_part(d) AMBA_PART_BITS((d)->periphid)
+
+#define __AMBA_DEV(busid, data) \
+ { \
+ .init_name = busid, \
+ .platform_data = data, \
+ }
+
+/*
+ * APB devices do not themselves have the ability to address memory,
+ * so DMA masks should be zero (much like USB peripheral devices.)
+ * The DMA controller DMA masks should be used instead (much like
+ * USB host controllers in conventional PCs.)
+ */
+#define AMBA_APB_DEVICE(name, busid, id, base, data) \
+struct amba_device name##_device = { \
+ .dev = __AMBA_DEV(busid, data), \
+ .res = DEFINE_RES_MEM(base, SZ_4K), \
+ .periphid = id, \
+}
+
+/*
+ * AHB devices are DMA capable, so set their DMA masks
+ */
+#define AMBA_AHB_DEVICE(name, busid, id, base, data) \
+struct amba_device name##_device = { \
+ .dev = __AMBA_DEV(busid, data), \
+ .res = DEFINE_RES_MEM(base, SZ_4K), \
+ .periphid = id, \
+}
+
+#endif
--
1.7.10.4
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