diff options
| -rw-r--r-- | arch/powerpc/include/asm/scom.h | 156 | ||||
| -rw-r--r-- | arch/powerpc/sysdev/Kconfig | 7 | ||||
| -rw-r--r-- | arch/powerpc/sysdev/Makefile | 2 | ||||
| -rw-r--r-- | arch/powerpc/sysdev/scom.c | 192 |
4 files changed, 357 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/scom.h b/arch/powerpc/include/asm/scom.h new file mode 100644 index 00000000000..0cabfd7bc2d --- /dev/null +++ b/arch/powerpc/include/asm/scom.h @@ -0,0 +1,156 @@ +/* + * Copyright 2010 Benjamin Herrenschmidt, IBM Corp + * <benh@kernel.crashing.org> + * and David Gibson, IBM Corporation. + * + * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#ifndef _ASM_POWERPC_SCOM_H +#define _ASM_POWERPC_SCOM_H + +#ifdef __KERNEL__ +#ifndef __ASSEMBLY__ +#ifdef CONFIG_PPC_SCOM + +/* + * The SCOM bus is a sideband bus used for accessing various internal + * registers of the processor or the chipset. The implementation details + * differ between processors and platforms, and the access method as + * well. + * + * This API allows to "map" ranges of SCOM register numbers associated + * with a given SCOM controller. The later must be represented by a + * device node, though some implementations might support NULL if there + * is no possible ambiguity + * + * Then, scom_read/scom_write can be used to accesses registers inside + * that range. The argument passed is a register number relative to + * the beginning of the range mapped. + */ + +typedef void *scom_map_t; + +/* Value for an invalid SCOM map */ +#define SCOM_MAP_INVALID (NULL) + +/* The scom_controller data structure is what the platform passes + * to the core code in scom_init, it provides the actual implementation + * of all the SCOM functions + */ +struct scom_controller { + scom_map_t (*map)(struct device_node *ctrl_dev, u64 reg, u64 count); + void (*unmap)(scom_map_t map); + + u64 (*read)(scom_map_t map, u32 reg); + void (*write)(scom_map_t map, u32 reg, u64 value); +}; + +extern const struct scom_controller *scom_controller; + +/** + * scom_init - Initialize the SCOM backend, called by the platform + * @controller: The platform SCOM controller + */ +static inline void scom_init(const struct scom_controller *controller) +{ + scom_controller = controller; +} + +/** + * scom_map_ok - Test is a SCOM mapping is successful + * @map: The result of scom_map to test + */ +static inline int scom_map_ok(scom_map_t map) +{ + return map != SCOM_MAP_INVALID; +} + +/** + * scom_map - Map a block of SCOM registers + * @ctrl_dev: Device node of the SCOM controller + * some implementations allow NULL here + * @reg: first SCOM register to map + * @count: Number of SCOM registers to map + */ + +static inline scom_map_t scom_map(struct device_node *ctrl_dev, + u64 reg, u64 count) +{ + return scom_controller->map(ctrl_dev, reg, count); +} + +/** + * scom_find_parent - Find the SCOM controller for a device + * @dev: OF node of the device + * + * This is not meant for general usage, but in combination with + * scom_map() allows to map registers not represented by the + * device own scom-reg property. Useful for applying HW workarounds + * on things not properly represented in the device-tree for example. + */ +struct device_node *scom_find_parent(struct device_node *dev); + + +/** + * scom_map_device - Map a device's block of SCOM registers + * @dev: OF node of the device + * @index: Register bank index (index in "scom-reg" property) + * + * This function will use the device-tree binding for SCOM which + * is to follow "scom-parent" properties until it finds a node with + * a "scom-controller" property to find the controller. It will then + * use the "scom-reg" property which is made of reg/count pairs, + * each of them having a size defined by the controller's #scom-cells + * property + */ +extern scom_map_t scom_map_device(struct device_node *dev, int index); + + +/** + * scom_unmap - Unmap a block of SCOM registers + * @map: Result of scom_map is to be unmapped + */ +static inline void scom_unmap(scom_map_t map) +{ + if (scom_map_ok(map)) + scom_controller->unmap(map); +} + +/** + * scom_read - Read a SCOM register + * @map: Result of scom_map + * @reg: Register index within that map + */ +static inline u64 scom_read(scom_map_t map, u32 reg) +{ + return scom_controller->read(map, reg); +} + +/** + * scom_write - Write to a SCOM register + * @map: Result of scom_map + * @reg: Register index within that map + * @value: Value to write + */ +static inline void scom_write(scom_map_t map, u32 reg, u64 value) +{ + scom_controller->write(map, reg, value); +} + +#endif /* CONFIG_PPC_SCOM */ +#endif /* __ASSEMBLY__ */ +#endif /* __KERNEL__ */ +#endif /* _ASM_POWERPC_SCOM_H */ diff --git a/arch/powerpc/sysdev/Kconfig b/arch/powerpc/sysdev/Kconfig index cfc18770af7..d775fd148d1 100644 --- a/arch/powerpc/sysdev/Kconfig +++ b/arch/powerpc/sysdev/Kconfig @@ -15,3 +15,10 @@ config PPC_MSI_BITMAP source "arch/powerpc/sysdev/xics/Kconfig" +config PPC_SCOM + bool + +config SCOM_DEBUGFS + bool "Expose SCOM controllers via debugfs" + depends on PPC_SCOM + default n diff --git a/arch/powerpc/sysdev/Makefile b/arch/powerpc/sysdev/Makefile index 9516e759857..6076e0074a8 100644 --- a/arch/powerpc/sysdev/Makefile +++ b/arch/powerpc/sysdev/Makefile @@ -58,6 +58,8 @@ ifeq ($(CONFIG_SUSPEND),y) obj-$(CONFIG_6xx) += 6xx-suspend.o endif +obj-$(CONFIG_PPC_SCOM) += scom.o + subdir-ccflags-$(CONFIG_PPC_WERROR) := -Werror obj-$(CONFIG_PPC_XICS) += xics/ diff --git a/arch/powerpc/sysdev/scom.c b/arch/powerpc/sysdev/scom.c new file mode 100644 index 00000000000..b2593ce30c9 --- /dev/null +++ b/arch/powerpc/sysdev/scom.c @@ -0,0 +1,192 @@ +/* + * Copyright 2010 Benjamin Herrenschmidt, IBM Corp + * <benh@kernel.crashing.org> + * and David Gibson, IBM Corporation. + * + * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include <linux/kernel.h> +#include <linux/debugfs.h> +#include <linux/slab.h> +#include <asm/prom.h> +#include <asm/scom.h> + +const struct scom_controller *scom_controller; +EXPORT_SYMBOL_GPL(scom_controller); + +struct device_node *scom_find_parent(struct device_node *node) +{ + struct device_node *par, *tmp; + const u32 *p; + + for (par = of_node_get(node); par;) { + if (of_get_property(par, "scom-controller", NULL)) + break; + p = of_get_property(par, "scom-parent", NULL); + tmp = par; + if (p == NULL) + par = of_get_parent(par); + else + par = of_find_node_by_phandle(*p); + of_node_put(tmp); + } + return par; +} +EXPORT_SYMBOL_GPL(scom_find_parent); + +scom_map_t scom_map_device(struct device_node *dev, int index) +{ + struct device_node *parent; + unsigned int cells, size; + const u32 *prop; + u64 reg, cnt; + scom_map_t ret; + + parent = scom_find_parent(dev); + + if (parent == NULL) + return 0; + + prop = of_get_property(parent, "#scom-cells", NULL); + cells = prop ? *prop : 1; + + prop = of_get_property(dev, "scom-reg", &size); + if (!prop) + return 0; + size >>= 2; + + if (index >= (size / (2*cells))) + return 0; + + reg = of_read_number(&prop[index * cells * 2], cells); + cnt = of_read_number(&prop[index * cells * 2 + cells], cells); + + ret = scom_map(parent, reg, cnt); + of_node_put(parent); + + return ret; +} +EXPORT_SYMBOL_GPL(scom_map_device); + +#ifdef CONFIG_SCOM_DEBUGFS +struct scom_debug_entry { + struct device_node *dn; + unsigned long addr; + scom_map_t map; + spinlock_t lock; + char name[8]; + struct debugfs_blob_wrapper blob; +}; + +static int scom_addr_set(void *data, u64 val) +{ + struct scom_debug_entry *ent = data; + + ent->addr = 0; + scom_unmap(ent->map); + + ent->map = scom_map(ent->dn, val, 1); + if (scom_map_ok(ent->map)) + ent->addr = val; + else + return -EFAULT; + + return 0; +} + +static int scom_addr_get(void *data, u64 *val) +{ + struct scom_debug_entry *ent = data; + *val = ent->addr; + return 0; +} +DEFINE_SIMPLE_ATTRIBUTE(scom_addr_fops, scom_addr_get, scom_addr_set, + "0x%llx\n"); + +static int scom_val_set(void *data, u64 val) +{ + struct scom_debug_entry *ent = data; + + if (!scom_map_ok(ent->map)) + return -EFAULT; + + scom_write(ent->map, 0, val); + + return 0; +} + +static int scom_val_get(void *data, u64 *val) +{ + struct scom_debug_entry *ent = data; + + if (!scom_map_ok(ent->map)) + return -EFAULT; + + *val = scom_read(ent->map, 0); + return 0; +} +DEFINE_SIMPLE_ATTRIBUTE(scom_val_fops, scom_val_get, scom_val_set, + "0x%llx\n"); + +static int scom_debug_init_one(struct dentry *root, struct device_node *dn, + int i) +{ + struct scom_debug_entry *ent; + struct dentry *dir; + + ent = kzalloc(sizeof(*ent), GFP_KERNEL); + if (!ent) + return -ENOMEM; + + ent->dn = of_node_get(dn); + ent->map = SCOM_MAP_INVALID; + spin_lock_init(&ent->lock); + snprintf(ent->name, 8, "scom%d", i); + ent->blob.data = dn->full_name; + ent->blob.size = strlen(dn->full_name); + + dir = debugfs_create_dir(ent->name, root); + if (!dir) { + of_node_put(dn); + kfree(ent); + return -1; + } + + debugfs_create_file("addr", 0600, dir, ent, &scom_addr_fops); + debugfs_create_file("value", 0600, dir, ent, &scom_val_fops); + debugfs_create_blob("path", 0400, dir, &ent->blob); + + return 0; +} + +static int scom_debug_init(void) +{ + struct device_node *dn; + struct dentry *root; + int i, rc; + + root = debugfs_create_dir("scom", powerpc_debugfs_root); + if (!root) + return -1; + + i = rc = 0; + for_each_node_with_property(dn, "scom-controller") + rc |= scom_debug_init_one(root, dn, i++); + + return rc; +} +device_initcall(scom_debug_init); +#endif /* CONFIG_SCOM_DEBUGFS */ |