The debugfs interface was essentially unused, and racy for anything
other than manual use by a developer. This provides a more useful
sysfs based one which can be used by programs without racing with
each other essentially by providing a file to read/write with an
offset being the scom address << 8.
It requires 8 bytes aligned and multiple of 8 bytes sized accesses
Signed-off-by: Benjamin Herrenschmidt <b...@kernel.crashing.org>
---
arch/powerpc/configs/chroma_defconfig | 2 +-
arch/powerpc/sysdev/Kconfig | 6 +-
arch/powerpc/sysdev/scom.c | 210 +++++++++++++++++++++-------------
3 files changed, 135 insertions(+), 83 deletions(-)
diff --git a/arch/powerpc/configs/chroma_defconfig
b/arch/powerpc/configs/chroma_defconfig
index 4f35fc4..2891464 100644
--- a/arch/powerpc/configs/chroma_defconfig
+++ b/arch/powerpc/configs/chroma_defconfig
@@ -42,7 +42,7 @@ CONFIG_MODULE_UNLOAD=y
CONFIG_MODULE_FORCE_UNLOAD=y
CONFIG_MODVERSIONS=y
CONFIG_MODULE_SRCVERSION_ALL=y
-CONFIG_SCOM_DEBUGFS=y
+CONFIG_SCOM_SYSFS=y
CONFIG_PPC_A2_DD2=y
CONFIG_KVM_GUEST=y
CONFIG_NO_HZ=y
diff --git a/arch/powerpc/sysdev/Kconfig b/arch/powerpc/sysdev/Kconfig
index 13ec968..30c26bb 100644
--- a/arch/powerpc/sysdev/Kconfig
+++ b/arch/powerpc/sysdev/Kconfig
@@ -26,9 +26,9 @@ source "arch/powerpc/sysdev/xics/Kconfig"
config PPC_SCOM
bool
-config SCOM_DEBUGFS
- bool "Expose SCOM controllers via debugfs"
- depends on PPC_SCOM && DEBUG_FS
+config SCOM_SYSFS
+ bool "Expose SCOM controllers via sysfs"
+ depends on PPC_SCOM
default n
config GE_FPGA
diff --git a/arch/powerpc/sysdev/scom.c b/arch/powerpc/sysdev/scom.c
index 3963d99..72eda2d 100644
--- a/arch/powerpc/sysdev/scom.c
+++ b/arch/powerpc/sysdev/scom.c
@@ -19,9 +19,10 @@
*/
#include <linux/kernel.h>
-#include <linux/debugfs.h>
#include <linux/slab.h>
#include <linux/export.h>
+#include <linux/kobject.h>
+#include <linux/sysfs.h>
#include <asm/debug.h>
#include <asm/prom.h>
#include <asm/scom.h>
@@ -95,116 +96,167 @@ scom_map_t scom_map_device(struct device_node *dev, int
index)
}
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;
+#ifdef CONFIG_SCOM_SYSFS
+
+struct scom_chip_dir {
+ struct kobject kobj;
+ struct device_node *devnode;
};
-static int scom_addr_set(void *data, u64 val)
+static struct scom_chip_dir *kobj_to_scom_chip_dir(struct kobject *k)
{
- 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;
+ return container_of(k, struct scom_chip_dir, kobj);
}
-static int scom_addr_get(void *data, u64 *val)
+static ssize_t scom_devspec_show(struct kobject *k, struct kobj_attribute
*attr,
+ char *buf)
{
- 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");
+ struct scom_chip_dir *dir = kobj_to_scom_chip_dir(k);
-static int scom_val_set(void *data, u64 val)
-{
- struct scom_debug_entry *ent = data;
+ return sprintf(buf, "%s", dir->devnode->full_name);
+}
- if (!scom_map_ok(ent->map))
- return -EFAULT;
+static struct kobj_attribute scom_devspec_attr =
+ __ATTR(devspec, S_IRUGO, scom_devspec_show, NULL);
- scom_write(ent->map, 0, val);
+static struct attribute *scom_dir_default_attrs[] = {
+ &scom_devspec_attr.attr,
+ NULL,
+};
- return 0;
+static void scom_dir_release(struct kobject *kobj)
+{
+ struct scom_chip_dir *dir = kobj_to_scom_chip_dir(kobj);
+ kfree(dir);
}
-static int scom_val_get(void *data, u64 *val)
-{
- struct scom_debug_entry *ent = data;
+static struct kobj_type scom_dir_type = {
+ .release = scom_dir_release,
+ .sysfs_ops = &kobj_sysfs_ops,
+ .default_attrs = scom_dir_default_attrs,
+};
- if (!scom_map_ok(ent->map))
- return -EFAULT;
+static ssize_t scom_sysfs_read(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr,
+ char *buf, loff_t off, size_t count)
+{
+ struct scom_chip_dir *dir = kobj_to_scom_chip_dir(kobj);
+ u64 reg, reg_cnt, *buf64;
+ scom_map_t map;
+ int rc;
+
+ if (off & 7 || count & 7)
+ return -EINVAL;
+ reg = off >> 3;
+ reg_cnt = count >> 3;
+
+ map = scom_map(dir->devnode, reg, reg_cnt);
+ if (!scom_map_ok(map))
+ return -EINVAL;
+
+ buf64 = (u64 *)buf;
+ for (reg = 0; reg < reg_cnt; reg++) {
+ rc = scom_read(map, reg, buf64++);
+ if (rc) {
+ count = rc;
+ break;
+ }
+ }
+ scom_unmap(map);
+ return count;
+}
- return scom_read(ent->map, 0, val);
+static ssize_t scom_sysfs_write(struct file* filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr,
+ char *buf, loff_t off, size_t count)
+{
+ struct scom_chip_dir *dir = kobj_to_scom_chip_dir(kobj);
+ u64 reg, reg_cnt, *buf64;
+ scom_map_t map;
+ int rc;
+
+ if (off & 7 || count & 7)
+ return -EINVAL;
+ reg = off >> 3;
+ reg_cnt = count >> 3;
+
+ map = scom_map(dir->devnode, reg, reg_cnt);
+ if (!scom_map_ok(map))
+ return -EINVAL;
+
+ buf64 = (u64 *)buf;
+ for (reg = 0; reg < reg_cnt; reg++) {
+ rc = scom_write(map, reg, *(buf64++));
+ if (rc) {
+ count = rc;
+ break;
+ }
+ }
+ scom_unmap(map);
+ return count;
}
-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)
+static struct bin_attribute scom_access_attr = {
+ .attr = {
+ .name = "access",
+ .mode = S_IRUSR | S_IWUSR,
+ },
+ .size = 0,
+ .read = scom_sysfs_read,
+ .write = scom_sysfs_write,
+};
+
+static int scom_sysfs_init_chip(struct kobject *root, struct device_node *dn,
+ int index)
{
- struct scom_debug_entry *ent;
- struct dentry *dir;
+ struct scom_chip_dir *dir;
+ int rc;
- ent = kzalloc(sizeof(*ent), GFP_KERNEL);
- if (!ent)
+ dir = kzalloc(sizeof(*dir), GFP_KERNEL);
+ if (!dir)
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 = (void*) 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;
+ dir->devnode = of_node_get(dn);
+
+ rc = kobject_init_and_add(&dir->kobj, &scom_dir_type,
+ root, "%08x", index);
+ if (rc) {
+ pr_err("scom: Failed to create kobj for %s, err %d\n",
+ dn->full_name, rc);
+ return rc;
}
- debugfs_create_file("addr", 0600, dir, ent, &scom_addr_fops);
- debugfs_create_file("value", 0600, dir, ent, &scom_val_fops);
- debugfs_create_blob("devspec", 0400, dir, &ent->blob);
+ rc = sysfs_create_bin_file(&dir->kobj, &scom_access_attr);
+ if (rc) {
+ pr_err("scom: Failed to create access file for %s, err %d\n",
+ dn->full_name, rc);
+ return rc;
+ }
return 0;
}
-static int scom_debug_init(void)
+static int scom_sysfs_init(void)
{
struct device_node *dn;
- struct dentry *root;
- int i, rc;
+ struct kobject *root = NULL;
+ int i;
- root = debugfs_create_dir("scom", powerpc_debugfs_root);
- if (!root)
- return -1;
-
- i = rc = 0;
+ i = 0;
for_each_node_with_property(dn, "scom-controller") {
int id = of_get_ibm_chip_id(dn);
if (id == -1)
id = i;
- rc |= scom_debug_init_one(root, dn, id);
+ if (!root)
+ root = kobject_create_and_add("scom", firmware_kobj);
+ if (!root) {
+ pr_err("scom: Failed to create sysfs root\n");
+ return -ENOMEM;
+ }
+ scom_sysfs_init_chip(root, dn, id);
i++;
}
-
- return rc;
+ return 0;
}
-device_initcall(scom_debug_init);
-#endif /* CONFIG_SCOM_DEBUGFS */
+subsys_initcall(scom_sysfs_init);
+
+#endif /* CONFIG_SCOM_SYSFS */
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