disable cpu isolcpus

hc

2023-12-09 958e46acc8e900e8569dd467c1af9b8d2d019394

 kernel/arch/powerpc/platforms/powernv/opal-xscom.c
..
..
@@ -1,12 +1,11 @@
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+// SPDX-License-Identifier: GPL-2.0-or-later
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2
 /*
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- * PowerNV LPC bus handling.
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+ * PowerNV SCOM bus debugfs interface
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  *
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+ * Copyright 2010 Benjamin Herrenschmidt, IBM Corp
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+ *                <benh@kernel.crashing.org>
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+ *     and        David Gibson, IBM Corporation.
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  * Copyright 2013 IBM Corp.
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- *
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- * This program is free software; you can redistribute it and/or
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- * modify it under the terms of the GNU General Public License
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- * as published by the Free Software Foundation; either version
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- * 2 of the License, or (at your option) any later version.
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  */
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10
 
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 #include <linux/kernel.h>
..
..
@@ -14,62 +13,13 @@
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 #include <linux/bug.h>
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 #include <linux/gfp.h>
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 #include <linux/slab.h>
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+#include <linux/uaccess.h>
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17
 
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 #include <asm/machdep.h>
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 #include <asm/firmware.h>
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 #include <asm/opal.h>
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-#include <asm/scom.h>
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-
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-/*
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- * We could probably fit that inside the scom_map_t
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- * which is a void* after all but it's really too ugly
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- * so let's kmalloc it for now
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- */
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-struct opal_scom_map {
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-	uint32_t chip;
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-	uint64_t addr;
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-};
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-
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-static scom_map_t opal_scom_map(struct device_node *dev, u64 reg, u64 count)
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-{
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-	struct opal_scom_map *m;
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-	const __be32 *gcid;
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-
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-	if (!of_get_property(dev, "scom-controller", NULL)) {
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-		pr_err("%s: device %pOF is not a SCOM controller\n",
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-			__func__, dev);
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-		return SCOM_MAP_INVALID;
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-	}
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-	gcid = of_get_property(dev, "ibm,chip-id", NULL);
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-	if (!gcid) {
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-		pr_err("%s: device %pOF has no ibm,chip-id\n",
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-			__func__, dev);
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-		return SCOM_MAP_INVALID;
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-	}
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-	m = kmalloc(sizeof(*m), GFP_KERNEL);
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-	if (!m)
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-		return NULL;
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-	m->chip = be32_to_cpup(gcid);
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-	m->addr = reg;
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-
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-	return (scom_map_t)m;
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-}
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-
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-static void opal_scom_unmap(scom_map_t map)
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-{
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-	kfree(map);
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-}
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-
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-static int opal_xscom_err_xlate(int64_t rc)
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-{
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-	switch(rc) {
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-	case 0:
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-		return 0;
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-	/* Add more translations if necessary */
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-	default:
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-		return -EIO;
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-	}
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-}
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+#include <asm/debugfs.h>
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+#include <asm/prom.h>
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23
 
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 static u64 opal_scom_unmangle(u64 addr)
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 {
..
..
@@ -102,39 +52,154 @@
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 	return addr;
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 }
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54
 
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-static int opal_scom_read(scom_map_t map, u64 reg, u64 *value)
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+static int opal_scom_read(uint32_t chip, uint64_t addr, u64 reg, u64 *value)
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 {
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-	struct opal_scom_map *m = map;
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 	int64_t rc;
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 	__be64 v;
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-	reg = opal_scom_unmangle(m->addr + reg);
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-	rc = opal_xscom_read(m->chip, reg, (__be64 *)__pa(&v));
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+	reg = opal_scom_unmangle(addr + reg);
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+	rc = opal_xscom_read(chip, reg, (__be64 *)__pa(&v));
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+	if (rc) {
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+		*value = 0xfffffffffffffffful;
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+		return -EIO;
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+	}
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 	*value = be64_to_cpu(v);
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-	return opal_xscom_err_xlate(rc);
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-}
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-
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-static int opal_scom_write(scom_map_t map, u64 reg, u64 value)
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-{
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-	struct opal_scom_map *m = map;
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-	int64_t rc;
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-
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-	reg = opal_scom_unmangle(m->addr + reg);
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-	rc = opal_xscom_write(m->chip, reg, value);
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-	return opal_xscom_err_xlate(rc);
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-}
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-
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-static const struct scom_controller opal_scom_controller = {
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-	.map	= opal_scom_map,
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-	.unmap	= opal_scom_unmap,
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-	.read	= opal_scom_read,
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-	.write	= opal_scom_write
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-};
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-
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-static int opal_xscom_init(void)
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-{
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-	if (firmware_has_feature(FW_FEATURE_OPAL))
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-		scom_init(&opal_scom_controller);
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67
 	return 0;
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68
 }
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-machine_arch_initcall(powernv, opal_xscom_init);
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+
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+static int opal_scom_write(uint32_t chip, uint64_t addr, u64 reg, u64 value)
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+{
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+	int64_t rc;
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+
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+	reg = opal_scom_unmangle(addr + reg);
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+	rc = opal_xscom_write(chip, reg, value);
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+	if (rc)
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+		return -EIO;
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+	return 0;
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+}
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+
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+struct scom_debug_entry {
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+	u32 chip;
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+	struct debugfs_blob_wrapper path;
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+	char name[16];
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+};
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+
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+static ssize_t scom_debug_read(struct file *filp, char __user *ubuf,
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+			       size_t count, loff_t *ppos)
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+{
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+	struct scom_debug_entry *ent = filp->private_data;
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+	u64 __user *ubuf64 = (u64 __user *)ubuf;
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+	loff_t off = *ppos;
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+	ssize_t done = 0;
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+	u64 reg, reg_base, reg_cnt, val;
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+	int rc;
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+
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+	if (off < 0 || (off & 7) || (count & 7))
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+		return -EINVAL;
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+	reg_base = off >> 3;
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+	reg_cnt = count >> 3;
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+
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+	for (reg = 0; reg < reg_cnt; reg++) {
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+		rc = opal_scom_read(ent->chip, reg_base, reg, &val);
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+		if (!rc)
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+			rc = put_user(val, ubuf64);
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+		if (rc) {
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+			if (!done)
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+				done = rc;
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+			break;
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+		}
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+		ubuf64++;
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+		*ppos += 8;
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+		done += 8;
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+	}
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+	return done;
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+}
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+
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+static ssize_t scom_debug_write(struct file *filp, const char __user *ubuf,
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+				size_t count, loff_t *ppos)
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+{
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+	struct scom_debug_entry *ent = filp->private_data;
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+	u64 __user *ubuf64 = (u64 __user *)ubuf;
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+	loff_t off = *ppos;
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+	ssize_t done = 0;
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+	u64 reg, reg_base, reg_cnt, val;
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+	int rc;
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+
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+	if (off < 0 || (off & 7) || (count & 7))
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+		return -EINVAL;
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+	reg_base = off >> 3;
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+	reg_cnt = count >> 3;
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+
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+	for (reg = 0; reg < reg_cnt; reg++) {
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+		rc = get_user(val, ubuf64);
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+		if (!rc)
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+			rc = opal_scom_write(ent->chip, reg_base, reg,  val);
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+		if (rc) {
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+			if (!done)
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+				done = rc;
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+			break;
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+		}
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+		ubuf64++;
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+		done += 8;
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+	}
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+	return done;
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+}
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+
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+static const struct file_operations scom_debug_fops = {
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+	.read =		scom_debug_read,
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+	.write =	scom_debug_write,
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+	.open =		simple_open,
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+	.llseek =	default_llseek,
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+};
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+
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+static int scom_debug_init_one(struct dentry *root, struct device_node *dn,
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+			       int chip)
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+{
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+	struct scom_debug_entry *ent;
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+	struct dentry *dir;
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+
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+	ent = kzalloc(sizeof(*ent), GFP_KERNEL);
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+	if (!ent)
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+		return -ENOMEM;
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+
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+	ent->chip = chip;
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+	snprintf(ent->name, 16, "%08x", chip);
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+	ent->path.data = (void *)kasprintf(GFP_KERNEL, "%pOF", dn);
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+	ent->path.size = strlen((char *)ent->path.data);
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+
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+	dir = debugfs_create_dir(ent->name, root);
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+	if (!dir) {
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+		kfree(ent->path.data);
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+		kfree(ent);
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+		return -1;
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+	}
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+
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+	debugfs_create_blob("devspec", 0400, dir, &ent->path);
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+	debugfs_create_file("access", 0600, dir, ent, &scom_debug_fops);
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+
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+	return 0;
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+}
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+
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+static int scom_debug_init(void)
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+{
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+	struct device_node *dn;
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+	struct dentry *root;
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+	int chip, rc;
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+
189
+	if (!firmware_has_feature(FW_FEATURE_OPAL))
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+		return 0;
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+
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+	root = debugfs_create_dir("scom", powerpc_debugfs_root);
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+	if (!root)
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+		return -1;
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+
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+	rc = 0;
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+	for_each_node_with_property(dn, "scom-controller") {
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+		chip = of_get_ibm_chip_id(dn);
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+		WARN_ON(chip == -1);
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+		rc |= scom_debug_init_one(root, dn, chip);
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+	}
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+
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+	return rc;
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+}
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+device_initcall(scom_debug_init);