[PATCH v2 1/5] powerpc/powernv: Move SCOM access code into powernv platform

[PATCH v2 1/5] powerpc/powernv: Move SCOM access code into powernv platform

[Andrew Donnellan]

The powernv platform is the only one that directly accesses SCOMs. Move the
support code to platforms/powernv, and get rid of the PPC_SCOM Kconfig
option, as SCOM support is always selected when compiling for powernv.

This also means that the Kconfig item for CONFIG_SCOM_DEBUGFS will actually
show up in menuconfig, as previously it was the only labelled option in
sysdev/Kconfig and wasn't actually in a menu.

Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
---
v1->v2:
- move scom.h as well (mpe)
- add all the other patches in this series
---
 arch/powerpc/platforms/powernv/Kconfig              |  5 ++++-
 arch/powerpc/platforms/powernv/Makefile             |  2 +-
 arch/powerpc/platforms/powernv/opal-xscom.c         |  3 ++-
 arch/powerpc/{sysdev => platforms/powernv}/scom.c   |  3 ++-
 .../{include/asm => platforms/powernv}/scom.h       | 13 +++----------
 arch/powerpc/sysdev/Kconfig                         |  7 -------
 arch/powerpc/sysdev/Makefile                        |  2 --
 7 files changed, 12 insertions(+), 23 deletions(-)
 rename arch/powerpc/{sysdev => platforms/powernv}/scom.c (99%)
 rename arch/powerpc/{include/asm => platforms/powernv}/scom.h (95%)

diff --git a/arch/powerpc/platforms/powernv/Kconfig b/arch/powerpc/platforms/powernv/Kconfig
index 850eee860cf2..938803eab0ad 100644
--- a/arch/powerpc/platforms/powernv/Kconfig
+++ b/arch/powerpc/platforms/powernv/Kconfig
@@ -12,7 +12,6 @@ config PPC_POWERNV
 	select EPAPR_BOOT
 	select PPC_INDIRECT_PIO
 	select PPC_UDBG_16550
-	select PPC_SCOM
 	select ARCH_RANDOM
 	select CPU_FREQ
 	select PPC_DOORBELL
@@ -47,3 +46,7 @@ config PPC_VAS
 	  VAS adapters are found in POWER9 based systems.
 
 	  If unsure, say N.
+
+config SCOM_DEBUGFS
+	bool "Expose SCOM controllers via debugfs"
+	depends on DEBUG_FS
diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile
index da2e99efbd04..4b1644150135 100644
--- a/arch/powerpc/platforms/powernv/Makefile
+++ b/arch/powerpc/platforms/powernv/Makefile
@@ -4,12 +4,12 @@ obj-y			+= idle.o opal-rtc.o opal-nvram.o opal-lpc.o opal-flash.o
 obj-y			+= rng.o opal-elog.o opal-dump.o opal-sysparam.o opal-sensor.o
 obj-y			+= opal-msglog.o opal-hmi.o opal-power.o opal-irqchip.o
 obj-y			+= opal-kmsg.o opal-powercap.o opal-psr.o opal-sensor-groups.o
+obj-y			+= opal-xscom.o scom.o
 
 obj-$(CONFIG_SMP)	+= smp.o subcore.o subcore-asm.o
 obj-$(CONFIG_PCI)	+= pci.o pci-ioda.o npu-dma.o pci-ioda-tce.o
 obj-$(CONFIG_CXL_BASE)	+= pci-cxl.o
 obj-$(CONFIG_EEH)	+= eeh-powernv.o
-obj-$(CONFIG_PPC_SCOM)	+= opal-xscom.o
 obj-$(CONFIG_MEMORY_FAILURE)	+= opal-memory-errors.o
 obj-$(CONFIG_OPAL_PRD)	+= opal-prd.o
 obj-$(CONFIG_PERF_EVENTS) += opal-imc.o
diff --git a/arch/powerpc/platforms/powernv/opal-xscom.c b/arch/powerpc/platforms/powernv/opal-xscom.c
index 22d5e1110dbb..66337d92cb63 100644
--- a/arch/powerpc/platforms/powernv/opal-xscom.c
+++ b/arch/powerpc/platforms/powernv/opal-xscom.c
@@ -18,7 +18,8 @@
 #include <asm/machdep.h>
 #include <asm/firmware.h>
 #include <asm/opal.h>
-#include <asm/scom.h>
+
+#include "scom.h"
 
 /*
  * We could probably fit that inside the scom_map_t
diff --git a/arch/powerpc/sysdev/scom.c b/arch/powerpc/platforms/powernv/scom.c
similarity index 99%
rename from arch/powerpc/sysdev/scom.c
rename to arch/powerpc/platforms/powernv/scom.c
index a707b24a7ddb..50c019d2ef45 100644
--- a/arch/powerpc/sysdev/scom.c
+++ b/arch/powerpc/platforms/powernv/scom.c
@@ -23,9 +23,10 @@
 #include <linux/export.h>
 #include <asm/debugfs.h>
 #include <asm/prom.h>
-#include <asm/scom.h>
 #include <linux/uaccess.h>
 
+#include "scom.h"
+
 const struct scom_controller *scom_controller;
 EXPORT_SYMBOL_GPL(scom_controller);
 
diff --git a/arch/powerpc/include/asm/scom.h b/arch/powerpc/platforms/powernv/scom.h
similarity index 95%
rename from arch/powerpc/include/asm/scom.h
rename to arch/powerpc/platforms/powernv/scom.h
index f5cde45b1161..b14fe0edf95b 100644
--- a/arch/powerpc/include/asm/scom.h
+++ b/arch/powerpc/platforms/powernv/scom.h
@@ -18,12 +18,8 @@
  *   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
+#ifndef _SCOM_H
+#define _SCOM_H
 
 /*
  * The SCOM bus is a sideband bus used for accessing various internal
@@ -161,7 +157,4 @@ static inline int scom_write(scom_map_t map, u64 reg, u64 value)
 }
 
 
-#endif /* CONFIG_PPC_SCOM */
-#endif /* __ASSEMBLY__ */
-#endif /* __KERNEL__ */
-#endif /* _ASM_POWERPC_SCOM_H */
+#endif /* _SCOM_H */
diff --git a/arch/powerpc/sysdev/Kconfig b/arch/powerpc/sysdev/Kconfig
index e0dbec780fe9..7808d279ff1d 100644
--- a/arch/powerpc/sysdev/Kconfig
+++ b/arch/powerpc/sysdev/Kconfig
@@ -28,13 +28,6 @@ config PPC_MSI_BITMAP
 source "arch/powerpc/sysdev/xics/Kconfig"
 source "arch/powerpc/sysdev/xive/Kconfig"
 
-config PPC_SCOM
-	bool
-
-config SCOM_DEBUGFS
-	bool "Expose SCOM controllers via debugfs"
-	depends on PPC_SCOM && DEBUG_FS
-
 config GE_FPGA
 	bool
 
diff --git a/arch/powerpc/sysdev/Makefile b/arch/powerpc/sysdev/Makefile
index aaf23283ba0c..35d52d1d2fc0 100644
--- a/arch/powerpc/sysdev/Makefile
+++ b/arch/powerpc/sysdev/Makefile
@@ -51,8 +51,6 @@ ifdef CONFIG_SUSPEND
 obj-$(CONFIG_PPC_BOOK3S_32)	+= 6xx-suspend.o
 endif
 
-obj-$(CONFIG_PPC_SCOM)		+= scom.o
-
 obj-$(CONFIG_PPC_EARLY_DEBUG_MEMCONS)	+= udbg_memcons.o
 
 obj-$(CONFIG_PPC_XICS)		+= xics/
-- 
2.20.1

[PATCH v2 2/5] powerpc/powernv: Remove dead SCOM access code

[Andrew Donnellan]

Nothing is using scom_map_device() or scom_find_parent(). Remove them.

Also don't export scom_controller, there are no other users of it.

Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
---
v1->v2:
- new patch
---
 arch/powerpc/platforms/powernv/scom.c | 67 ---------------------------
 arch/powerpc/platforms/powernv/scom.h | 27 -----------
 2 files changed, 94 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/scom.c b/arch/powerpc/platforms/powernv/scom.c
index 50c019d2ef45..288580e5fdfe 100644
--- a/arch/powerpc/platforms/powernv/scom.c
+++ b/arch/powerpc/platforms/powernv/scom.c
@@ -28,73 +28,6 @@
 #include "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 __be32 *prop, *sprop;
-	u64 reg, cnt;
-	scom_map_t ret;
-
-	parent = scom_find_parent(dev);
-
-	if (parent == NULL)
-		return NULL;
-
-	/*
-	 * We support "scom-reg" properties for adding scom registers
-	 * to a random device-tree node with an explicit scom-parent
-	 *
-	 * We also support the simple "reg" property if the device is
-	 * a direct child of a scom controller.
-	 *
-	 * In case both exist, "scom-reg" takes precedence.
-	 */
-	prop = of_get_property(dev, "scom-reg", &size);
-	sprop = of_get_property(parent, "#scom-cells", NULL);
-	if (!prop && parent == dev->parent) {
-		prop = of_get_property(dev, "reg", &size);
-		sprop = of_get_property(parent, "#address-cells", NULL);
-	}
-	if (!prop)
-		return NULL;
-	cells = sprop ? be32_to_cpup(sprop) : 1;
-	size >>= 2;
-
-	if (index >= (size / (2*cells)))
-		return NULL;
-
-	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 {
diff --git a/arch/powerpc/platforms/powernv/scom.h b/arch/powerpc/platforms/powernv/scom.h
index b14fe0edf95b..2c72f7fc8726 100644
--- a/arch/powerpc/platforms/powernv/scom.h
+++ b/arch/powerpc/platforms/powernv/scom.h
@@ -88,33 +88,6 @@ static inline scom_map_t scom_map(struct device_node *ctrl_dev,
 	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
-- 
2.20.1

[PATCH v2 3/5] powerpc/powernv: Get rid of old scom_controller abstraction

[Andrew Donnellan]

Once upon a time, the SCOM access code was used by the WSP platform as well
as powernv. Thus it made sense to have a generic SCOM access interface to
abstract between different platforms.

Now that it's just powernv, with no other platforms currently on the
horizon, let's rip out scom_controller and make everything much simpler and
more direct.

While we're here, fix up the comment block at the top and add a SPDX
header.

Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
---
v1->v2:
- new patch
---
 arch/powerpc/platforms/powernv/Makefile     |   2 +-
 arch/powerpc/platforms/powernv/opal-xscom.c | 215 +++++++++++++-------
 arch/powerpc/platforms/powernv/scom.c       | 170 ----------------
 arch/powerpc/platforms/powernv/scom.h       | 133 ------------
 4 files changed, 143 insertions(+), 377 deletions(-)
 delete mode 100644 arch/powerpc/platforms/powernv/scom.c
 delete mode 100644 arch/powerpc/platforms/powernv/scom.h

diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile
index 4b1644150135..69a3aefa905b 100644
--- a/arch/powerpc/platforms/powernv/Makefile
+++ b/arch/powerpc/platforms/powernv/Makefile
@@ -4,7 +4,6 @@ obj-y			+= idle.o opal-rtc.o opal-nvram.o opal-lpc.o opal-flash.o
 obj-y			+= rng.o opal-elog.o opal-dump.o opal-sysparam.o opal-sensor.o
 obj-y			+= opal-msglog.o opal-hmi.o opal-power.o opal-irqchip.o
 obj-y			+= opal-kmsg.o opal-powercap.o opal-psr.o opal-sensor-groups.o
-obj-y			+= opal-xscom.o scom.o
 
 obj-$(CONFIG_SMP)	+= smp.o subcore.o subcore-asm.o
 obj-$(CONFIG_PCI)	+= pci.o pci-ioda.o npu-dma.o pci-ioda-tce.o
@@ -16,3 +15,4 @@ obj-$(CONFIG_PERF_EVENTS) += opal-imc.o
 obj-$(CONFIG_PPC_MEMTRACE)	+= memtrace.o
 obj-$(CONFIG_PPC_VAS)	+= vas.o vas-window.o vas-debug.o
 obj-$(CONFIG_OCXL_BASE)	+= ocxl.o
+obj-$(CONFIG_SCOM_DEBUGFS) += opal-xscom.o
diff --git a/arch/powerpc/platforms/powernv/opal-xscom.c b/arch/powerpc/platforms/powernv/opal-xscom.c
index 66337d92cb63..e16b0e346d7e 100644
--- a/arch/powerpc/platforms/powernv/opal-xscom.c
+++ b/arch/powerpc/platforms/powernv/opal-xscom.c
@@ -1,6 +1,10 @@
+// SPDX-License-Identifier:  GPL-2.0+
 /*
- * PowerNV LPC bus handling.
+ * PowerNV SCOM bus debugfs interface
  *
+ * Copyright 2010 Benjamin Herrenschmidt, IBM Corp
+ *                <benh@kernel.crashing.org>
+ *     and        David Gibson, IBM Corporation.
  * Copyright 2013 IBM Corp.
  *
  * This program is free software; you can redistribute it and/or
@@ -14,63 +18,13 @@
 #include <linux/bug.h>
 #include <linux/gfp.h>
 #include <linux/slab.h>
+#include <linux/uaccess.h>
 
 #include <asm/machdep.h>
 #include <asm/firmware.h>
 #include <asm/opal.h>
-
-#include "scom.h"
-
-/*
- * We could probably fit that inside the scom_map_t
- * which is a void* after all but it's really too ugly
- * so let's kmalloc it for now
- */
-struct opal_scom_map {
-	uint32_t chip;
-	uint64_t addr;
-};
-
-static scom_map_t opal_scom_map(struct device_node *dev, u64 reg, u64 count)
-{
-	struct opal_scom_map *m;
-	const __be32 *gcid;
-
-	if (!of_get_property(dev, "scom-controller", NULL)) {
-		pr_err("%s: device %pOF is not a SCOM controller\n",
-			__func__, dev);
-		return SCOM_MAP_INVALID;
-	}
-	gcid = of_get_property(dev, "ibm,chip-id", NULL);
-	if (!gcid) {
-		pr_err("%s: device %pOF has no ibm,chip-id\n",
-			__func__, dev);
-		return SCOM_MAP_INVALID;
-	}
-	m = kmalloc(sizeof(*m), GFP_KERNEL);
-	if (!m)
-		return NULL;
-	m->chip = be32_to_cpup(gcid);
-	m->addr = reg;
-
-	return (scom_map_t)m;
-}
-
-static void opal_scom_unmap(scom_map_t map)
-{
-	kfree(map);
-}
-
-static int opal_xscom_err_xlate(int64_t rc)
-{
-	switch(rc) {
-	case 0:
-		return 0;
-	/* Add more translations if necessary */
-	default:
-		return -EIO;
-	}
-}
+#include <asm/debugfs.h>
+#include <asm/prom.h>
 
 static u64 opal_scom_unmangle(u64 addr)
 {
@@ -103,39 +57,154 @@ static u64 opal_scom_unmangle(u64 addr)
 	return addr;
 }
 
-static int opal_scom_read(scom_map_t map, u64 reg, u64 *value)
+static int opal_scom_read(uint32_t chip, uint64_t addr, u64 reg, u64 *value)
 {
-	struct opal_scom_map *m = map;
 	int64_t rc;
 	__be64 v;
 
-	reg = opal_scom_unmangle(m->addr + reg);
-	rc = opal_xscom_read(m->chip, reg, (__be64 *)__pa(&v));
+	reg = opal_scom_unmangle(addr + reg);
+	rc = opal_xscom_read(chip, reg, (__be64 *)__pa(&v));
+	if (rc) {
+		*value = 0xfffffffffffffffful;
+		return -EIO;
+	}
 	*value = be64_to_cpu(v);
-	return opal_xscom_err_xlate(rc);
+	return 0;
 }
 
-static int opal_scom_write(scom_map_t map, u64 reg, u64 value)
+static int opal_scom_write(uint32_t chip, uint64_t addr, u64 reg, u64 value)
 {
-	struct opal_scom_map *m = map;
 	int64_t rc;
 
-	reg = opal_scom_unmangle(m->addr + reg);
-	rc = opal_xscom_write(m->chip, reg, value);
-	return opal_xscom_err_xlate(rc);
+	reg = opal_scom_unmangle(addr + reg);
+	rc = opal_xscom_write(chip, reg, value);
+	if (rc)
+		return -EIO;
+	return 0;
+}
+
+struct scom_debug_entry {
+	u32 chip;
+	struct debugfs_blob_wrapper path;
+	char name[16];
+};
+
+static ssize_t scom_debug_read(struct file *filp, char __user *ubuf,
+			       size_t count, loff_t *ppos)
+{
+	struct scom_debug_entry *ent = filp->private_data;
+	u64 __user *ubuf64 = (u64 __user *)ubuf;
+	loff_t off = *ppos;
+	ssize_t done = 0; 
+	u64 reg, reg_base, reg_cnt, val;
+	int rc;
+
+	if (off < 0 || (off & 7) || (count & 7))
+		return -EINVAL;
+	reg_base = off >> 3;
+	reg_cnt = count >> 3;
+
+	for (reg = 0; reg < reg_cnt; reg++) {
+		rc = opal_scom_read(ent->chip, reg_base, reg, &val);
+		if (!rc)
+			rc = put_user(val, ubuf64);
+		if (rc) {
+			if (!done)
+				done = rc;
+			break;
+		}
+		ubuf64++;
+		*ppos += 8;
+		done += 8;
+	}
+	return done;
+}
+
+static ssize_t scom_debug_write(struct file* filp, const char __user *ubuf,
+				size_t count, loff_t *ppos)
+{
+	struct scom_debug_entry *ent = filp->private_data;
+	u64 __user *ubuf64 = (u64 __user *)ubuf;
+	loff_t off = *ppos;
+	ssize_t done = 0; 
+	u64 reg, reg_base, reg_cnt, val;
+	int rc;
+
+	if (off < 0 || (off & 7) || (count & 7))
+		return -EINVAL;
+	reg_base = off >> 3;
+	reg_cnt = count >> 3;
+
+	for (reg = 0; reg < reg_cnt; reg++) {
+		rc = get_user(val, ubuf64);
+		if (!rc)
+			rc = opal_scom_write(ent->chip, reg_base, reg,  val);
+		if (rc) {
+			if (!done)
+				done = rc;
+			break;
+		}
+		ubuf64++;
+		done += 8;
+	}
+	return done;
 }
 
-static const struct scom_controller opal_scom_controller = {
-	.map	= opal_scom_map,
-	.unmap	= opal_scom_unmap,
-	.read	= opal_scom_read,
-	.write	= opal_scom_write
+static const struct file_operations scom_debug_fops = {
+	.read =		scom_debug_read,
+	.write =	scom_debug_write,
+	.open =		simple_open,
+	.llseek =	default_llseek,
 };
 
-static int opal_xscom_init(void)
+static int scom_debug_init_one(struct dentry *root, struct device_node *dn,
+			       int chip)
 {
-	if (firmware_has_feature(FW_FEATURE_OPAL))
-		scom_init(&opal_scom_controller);
+	struct scom_debug_entry *ent;
+	struct dentry *dir;
+
+	ent = kzalloc(sizeof(*ent), GFP_KERNEL);
+	if (!ent)
+		return -ENOMEM;
+
+	ent->chip = chip;
+	snprintf(ent->name, 16, "%08x", chip);
+	ent->path.data = (void*)kasprintf(GFP_KERNEL, "%pOF", dn);
+	ent->path.size = strlen((char *)ent->path.data);
+
+	dir = debugfs_create_dir(ent->name, root);
+	if (!dir) {
+		kfree(ent->path.data);
+		kfree(ent);
+		return -1;
+	}
+
+	debugfs_create_blob("devspec", 0400, dir, &ent->path);
+	debugfs_create_file("access", 0600, dir, ent, &scom_debug_fops);
+
 	return 0;
 }
-machine_arch_initcall(powernv, opal_xscom_init);
+
+static int scom_debug_init(void)
+{
+	struct device_node *dn;
+	struct dentry *root;
+	int chip, rc;
+
+	if (!firmware_has_feature(FW_FEATURE_OPAL))
+		return 0;
+
+	root = debugfs_create_dir("scom", powerpc_debugfs_root);
+	if (!root)
+		return -1;
+
+	rc = 0;
+	for_each_node_with_property(dn, "scom-controller") {
+		chip = of_get_ibm_chip_id(dn);
+		WARN_ON(chip == -1);
+		rc |= scom_debug_init_one(root, dn, chip);
+	}
+
+	return rc;
+}
+device_initcall(scom_debug_init);
diff --git a/arch/powerpc/platforms/powernv/scom.c b/arch/powerpc/platforms/powernv/scom.c
deleted file mode 100644
index 288580e5fdfe..000000000000
--- a/arch/powerpc/platforms/powernv/scom.c
+++ /dev/null
@@ -1,170 +0,0 @@
-/*
- * 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/slab.h>
-#include <linux/export.h>
-#include <asm/debugfs.h>
-#include <asm/prom.h>
-#include <linux/uaccess.h>
-
-#include "scom.h"
-
-const struct scom_controller *scom_controller;
-
-#ifdef CONFIG_SCOM_DEBUGFS
-struct scom_debug_entry {
-	struct device_node *dn;
-	struct debugfs_blob_wrapper path;
-	char name[16];
-};
-
-static ssize_t scom_debug_read(struct file *filp, char __user *ubuf,
-			       size_t count, loff_t *ppos)
-{
-	struct scom_debug_entry *ent = filp->private_data;
-	u64 __user *ubuf64 = (u64 __user *)ubuf;
-	loff_t off = *ppos;
-	ssize_t done = 0; 
-	u64 reg, reg_cnt, val;
-	scom_map_t map;
-	int rc;
-
-	if (off < 0 || (off & 7) || (count & 7))
-		return -EINVAL;
-	reg = off >> 3;
-	reg_cnt = count >> 3;
-
-	map = scom_map(ent->dn, reg, reg_cnt);
-	if (!scom_map_ok(map))
-		return -ENXIO;
-
-	for (reg = 0; reg < reg_cnt; reg++) {
-		rc = scom_read(map, reg, &val);
-		if (!rc)
-			rc = put_user(val, ubuf64);
-		if (rc) {
-			if (!done)
-				done = rc;
-			break;
-		}
-		ubuf64++;
-		*ppos += 8;
-		done += 8;
-	}
-	scom_unmap(map);
-	return done;
-}
-
-static ssize_t scom_debug_write(struct file* filp, const char __user *ubuf,
-				size_t count, loff_t *ppos)
-{
-	struct scom_debug_entry *ent = filp->private_data;
-	u64 __user *ubuf64 = (u64 __user *)ubuf;
-	loff_t off = *ppos;
-	ssize_t done = 0; 
-	u64 reg, reg_cnt, val;
-	scom_map_t map;
-	int rc;
-
-	if (off < 0 || (off & 7) || (count & 7))
-		return -EINVAL;
-	reg = off >> 3;
-	reg_cnt = count >> 3;
-
-	map = scom_map(ent->dn, reg, reg_cnt);
-	if (!scom_map_ok(map))
-		return -ENXIO;
-
-	for (reg = 0; reg < reg_cnt; reg++) {
-		rc = get_user(val, ubuf64);
-		if (!rc)
-			rc = scom_write(map, reg,  val);
-		if (rc) {
-			if (!done)
-				done = rc;
-			break;
-		}
-		ubuf64++;
-		done += 8;
-	}
-	scom_unmap(map);
-	return done;
-}
-
-static const struct file_operations scom_debug_fops = {
-	.read =		scom_debug_read,
-	.write =	scom_debug_write,
-	.open =		simple_open,
-	.llseek =	default_llseek,
-};
-
-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);
-	snprintf(ent->name, 16, "%08x", i);
-	ent->path.data = (void*)kasprintf(GFP_KERNEL, "%pOF", dn);
-	ent->path.size = strlen((char *)ent->path.data);
-
-	dir = debugfs_create_dir(ent->name, root);
-	if (!dir) {
-		of_node_put(dn);
-		kfree(ent->path.data);
-		kfree(ent);
-		return -1;
-	}
-
-	debugfs_create_blob("devspec", 0400, dir, &ent->path);
-	debugfs_create_file("access", 0600, dir, ent, &scom_debug_fops);
-
-	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") {
-		int id = of_get_ibm_chip_id(dn);
-		if (id == -1)
-			id = i;
-		rc |= scom_debug_init_one(root, dn, id);
-		i++;
-	}
-
-	return rc;
-}
-device_initcall(scom_debug_init);
-#endif /* CONFIG_SCOM_DEBUGFS */
diff --git a/arch/powerpc/platforms/powernv/scom.h b/arch/powerpc/platforms/powernv/scom.h
deleted file mode 100644
index 2c72f7fc8726..000000000000
--- a/arch/powerpc/platforms/powernv/scom.h
+++ /dev/null
@@ -1,133 +0,0 @@
-/*
- * 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 _SCOM_H
-#define _SCOM_H
-
-/*
- * 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);
-
-	int (*read)(scom_map_t map, u64 reg, u64 *value);
-	int (*write)(scom_map_t map, u64 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_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
- * @value: Updated with the value read
- *
- * Returns 0 (success) or a negative error code
- */
-static inline int scom_read(scom_map_t map, u64 reg, u64 *value)
-{
-	int rc;
-
-	rc = scom_controller->read(map, reg, value);
-	if (rc)
-		*value = 0xfffffffffffffffful;
-	return rc;
-}
-
-/**
- * scom_write - Write to a SCOM register
- * @map: Result of scom_map
- * @reg: Register index within that map
- * @value: Value to write
- *
- * Returns 0 (success) or a negative error code
- */
-static inline int scom_write(scom_map_t map, u64 reg, u64 value)
-{
-	return scom_controller->write(map, reg, value);
-}
-
-
-#endif /* _SCOM_H */
-- 
2.20.1

[PATCH v2 4/5] powerpc/powernv: Fix checkpatch warnings in opal-xscom.c

[Andrew Donnellan]

Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
---
v1->v2:
- new patch
---
 arch/powerpc/platforms/powernv/opal-xscom.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/opal-xscom.c b/arch/powerpc/platforms/powernv/opal-xscom.c
index e16b0e346d7e..d9607376822c 100644
--- a/arch/powerpc/platforms/powernv/opal-xscom.c
+++ b/arch/powerpc/platforms/powernv/opal-xscom.c
@@ -95,7 +95,7 @@ static ssize_t scom_debug_read(struct file *filp, char __user *ubuf,
 	struct scom_debug_entry *ent = filp->private_data;
 	u64 __user *ubuf64 = (u64 __user *)ubuf;
 	loff_t off = *ppos;
-	ssize_t done = 0; 
+	ssize_t done = 0;
 	u64 reg, reg_base, reg_cnt, val;
 	int rc;
 
@@ -120,13 +120,13 @@ static ssize_t scom_debug_read(struct file *filp, char __user *ubuf,
 	return done;
 }
 
-static ssize_t scom_debug_write(struct file* filp, const char __user *ubuf,
+static ssize_t scom_debug_write(struct file *filp, const char __user *ubuf,
 				size_t count, loff_t *ppos)
 {
 	struct scom_debug_entry *ent = filp->private_data;
 	u64 __user *ubuf64 = (u64 __user *)ubuf;
 	loff_t off = *ppos;
-	ssize_t done = 0; 
+	ssize_t done = 0;
 	u64 reg, reg_base, reg_cnt, val;
 	int rc;
 
@@ -169,7 +169,7 @@ static int scom_debug_init_one(struct dentry *root, struct device_node *dn,
 
 	ent->chip = chip;
 	snprintf(ent->name, 16, "%08x", chip);
-	ent->path.data = (void*)kasprintf(GFP_KERNEL, "%pOF", dn);
+	ent->path.data = (void *)kasprintf(GFP_KERNEL, "%pOF", dn);
 	ent->path.size = strlen((char *)ent->path.data);
 
 	dir = debugfs_create_dir(ent->name, root);
-- 
2.20.1

[PATCH v2 5/5] powerpc/configs: Disable SCOM_DEBUGFS in powernv_defconfig

[Andrew Donnellan]

SCOM_DEBUGFS is really not needed for anything other than low-level
hardware debugging.

opal-prd uses its own interface (/dev/prd) for SCOM access, so it doesn't
need SCOM_DEBUGFS.

At some point in the future we'll introduce a debug config fragment where
this can go instead.

Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
---
v1->v2:
- new patch
---
 arch/powerpc/configs/powernv_defconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/configs/powernv_defconfig b/arch/powerpc/configs/powernv_defconfig
index ef2ef98d3f28..d5a6608cb2e0 100644
--- a/arch/powerpc/configs/powernv_defconfig
+++ b/arch/powerpc/configs/powernv_defconfig
@@ -38,7 +38,7 @@ CONFIG_MODULE_UNLOAD=y
 CONFIG_MODVERSIONS=y
 CONFIG_MODULE_SRCVERSION_ALL=y
 CONFIG_PARTITION_ADVANCED=y
-CONFIG_SCOM_DEBUGFS=y
+# CONFIG_SCOM_DEBUGFS is not set
 CONFIG_OPAL_PRD=y
 CONFIG_PPC_MEMTRACE=y
 # CONFIG_PPC_PSERIES is not set
-- 
2.20.1

Re: [PATCH v2 5/5] powerpc/configs: Disable SCOM_DEBUGFS in powernv_defconfig

[Nicholas Piggin]

Andrew Donnellan's on May 9, 2019 3:11 pm:
> SCOM_DEBUGFS is really not needed for anything other than low-level
> hardware debugging.
> 
> opal-prd uses its own interface (/dev/prd) for SCOM access, so it doesn't
> need SCOM_DEBUGFS.
> 
> At some point in the future we'll introduce a debug config fragment where
> this can go instead.

That doesn't really explain why you want to disable it. It is useful
for low level hardware debugging, I added it.

obscurity^Wsecurity?

> 
> Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
> ---
> v1->v2:
> - new patch
> ---
>  arch/powerpc/configs/powernv_defconfig | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/configs/powernv_defconfig b/arch/powerpc/configs/powernv_defconfig
> index ef2ef98d3f28..d5a6608cb2e0 100644
> --- a/arch/powerpc/configs/powernv_defconfig
> +++ b/arch/powerpc/configs/powernv_defconfig
> @@ -38,7 +38,7 @@ CONFIG_MODULE_UNLOAD=y
>  CONFIG_MODVERSIONS=y
>  CONFIG_MODULE_SRCVERSION_ALL=y
>  CONFIG_PARTITION_ADVANCED=y
> -CONFIG_SCOM_DEBUGFS=y
> +# CONFIG_SCOM_DEBUGFS is not set
>  CONFIG_OPAL_PRD=y
>  CONFIG_PPC_MEMTRACE=y
>  # CONFIG_PPC_PSERIES is not set
> -- 
> 2.20.1
> 
> 

Re: [PATCH v2 5/5] powerpc/configs: Disable SCOM_DEBUGFS in powernv_defconfig

[Oliver]

On Thu, May 9, 2019 at 3:38 PM Nicholas Piggin <npiggin@gmail.com> wrote:
>
> Andrew Donnellan's on May 9, 2019 3:11 pm:
> > SCOM_DEBUGFS is really not needed for anything other than low-level
> > hardware debugging.
> >
> > opal-prd uses its own interface (/dev/prd) for SCOM access, so it doesn't
> > need SCOM_DEBUGFS.
> >
> > At some point in the future we'll introduce a debug config fragment where
> > this can go instead.
>
> That doesn't really explain why you want to disable it. It is useful
> for low level hardware debugging, I added it.
>
> obscurity^Wsecurity?

Yeah... If you're building powernv_defconfig then the odds are pretty
high that you'll want scom access.

>
> >
> > Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
> > ---
> > v1->v2:
> > - new patch
> > ---
> >  arch/powerpc/configs/powernv_defconfig | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/powerpc/configs/powernv_defconfig b/arch/powerpc/configs/powernv_defconfig
> > index ef2ef98d3f28..d5a6608cb2e0 100644
> > --- a/arch/powerpc/configs/powernv_defconfig
> > +++ b/arch/powerpc/configs/powernv_defconfig
> > @@ -38,7 +38,7 @@ CONFIG_MODULE_UNLOAD=y
> >  CONFIG_MODVERSIONS=y
> >  CONFIG_MODULE_SRCVERSION_ALL=y
> >  CONFIG_PARTITION_ADVANCED=y
> > -CONFIG_SCOM_DEBUGFS=y
> > +# CONFIG_SCOM_DEBUGFS is not set
> >  CONFIG_OPAL_PRD=y
> >  CONFIG_PPC_MEMTRACE=y
> >  # CONFIG_PPC_PSERIES is not set
> > --
> > 2.20.1
> >
> >

Re: [PATCH v2 5/5] powerpc/configs: Disable SCOM_DEBUGFS in powernv_defconfig

[Andrew Donnellan]

On 9/5/19 3:37 pm, Nicholas Piggin wrote:
> Andrew Donnellan's on May 9, 2019 3:11 pm:
>> SCOM_DEBUGFS is really not needed for anything other than low-level
>> hardware debugging.
>>
>> opal-prd uses its own interface (/dev/prd) for SCOM access, so it doesn't
>> need SCOM_DEBUGFS.
>>
>> At some point in the future we'll introduce a debug config fragment where
>> this can go instead.
> 
> That doesn't really explain why you want to disable it. It is useful
> for low level hardware debugging, I added it.
> 
> obscurity^Wsecurity?

Mostly just a general feeling that it's not something we need to have by 
default. Security-wise, PRD still provides SCOM access, though we are 
going to look at how we can further lock that down. Shrinks the build by 
only a few kilobytes...

mpe said he's planning on adding a debug.config where we can shift stuff 
like this, and if/when we do that I would like to see this moved there, 
but perhaps this patch can wait until then. I'll let mpe decide.


Andrew


> 
>>
>> Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
>> ---
>> v1->v2:
>> - new patch
>> ---
>>   arch/powerpc/configs/powernv_defconfig | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/configs/powernv_defconfig b/arch/powerpc/configs/powernv_defconfig
>> index ef2ef98d3f28..d5a6608cb2e0 100644
>> --- a/arch/powerpc/configs/powernv_defconfig
>> +++ b/arch/powerpc/configs/powernv_defconfig
>> @@ -38,7 +38,7 @@ CONFIG_MODULE_UNLOAD=y
>>   CONFIG_MODVERSIONS=y
>>   CONFIG_MODULE_SRCVERSION_ALL=y
>>   CONFIG_PARTITION_ADVANCED=y
>> -CONFIG_SCOM_DEBUGFS=y
>> +# CONFIG_SCOM_DEBUGFS is not set
>>   CONFIG_OPAL_PRD=y
>>   CONFIG_PPC_MEMTRACE=y
>>   # CONFIG_PPC_PSERIES is not set
>> -- 
>> 2.20.1
>>
>>
> 

-- 
Andrew Donnellan              OzLabs, ADL Canberra
ajd@linux.ibm.com             IBM Australia Limited

Re: [PATCH v2 1/5] powerpc/powernv: Move SCOM access code into powernv platform

[Andrew Donnellan]

On 9/5/19 3:11 pm, Andrew Donnellan wrote:
> The powernv platform is the only one that directly accesses SCOMs. Move the
> support code to platforms/powernv, and get rid of the PPC_SCOM Kconfig
> option, as SCOM support is always selected when compiling for powernv.
> 
> This also means that the Kconfig item for CONFIG_SCOM_DEBUGFS will actually
> show up in menuconfig, as previously it was the only labelled option in
> sysdev/Kconfig and wasn't actually in a menu.

As I've just realised, this isn't actually correct - the option does 
indeed show up... in the root menu, where I've just been trained to 
ignore it, and where you won't get a menu location if you try to search 
for it using / in menuconfig.

I think moving it to the platform menu is obviously a better location. 
mpe would you be able to fix up the commit message in merge?


Andrew


> 
> Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
> ---
> v1->v2:
> - move scom.h as well (mpe)
> - add all the other patches in this series
> ---
>   arch/powerpc/platforms/powernv/Kconfig              |  5 ++++-
>   arch/powerpc/platforms/powernv/Makefile             |  2 +-
>   arch/powerpc/platforms/powernv/opal-xscom.c         |  3 ++-
>   arch/powerpc/{sysdev => platforms/powernv}/scom.c   |  3 ++-
>   .../{include/asm => platforms/powernv}/scom.h       | 13 +++----------
>   arch/powerpc/sysdev/Kconfig                         |  7 -------
>   arch/powerpc/sysdev/Makefile                        |  2 --
>   7 files changed, 12 insertions(+), 23 deletions(-)
>   rename arch/powerpc/{sysdev => platforms/powernv}/scom.c (99%)
>   rename arch/powerpc/{include/asm => platforms/powernv}/scom.h (95%)
> 
> diff --git a/arch/powerpc/platforms/powernv/Kconfig b/arch/powerpc/platforms/powernv/Kconfig
> index 850eee860cf2..938803eab0ad 100644
> --- a/arch/powerpc/platforms/powernv/Kconfig
> +++ b/arch/powerpc/platforms/powernv/Kconfig
> @@ -12,7 +12,6 @@ config PPC_POWERNV
>   	select EPAPR_BOOT
>   	select PPC_INDIRECT_PIO
>   	select PPC_UDBG_16550
> -	select PPC_SCOM
>   	select ARCH_RANDOM
>   	select CPU_FREQ
>   	select PPC_DOORBELL
> @@ -47,3 +46,7 @@ config PPC_VAS
>   	  VAS adapters are found in POWER9 based systems.
>   
>   	  If unsure, say N.
> +
> +config SCOM_DEBUGFS
> +	bool "Expose SCOM controllers via debugfs"
> +	depends on DEBUG_FS
> diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile
> index da2e99efbd04..4b1644150135 100644
> --- a/arch/powerpc/platforms/powernv/Makefile
> +++ b/arch/powerpc/platforms/powernv/Makefile
> @@ -4,12 +4,12 @@ obj-y			+= idle.o opal-rtc.o opal-nvram.o opal-lpc.o opal-flash.o
>   obj-y			+= rng.o opal-elog.o opal-dump.o opal-sysparam.o opal-sensor.o
>   obj-y			+= opal-msglog.o opal-hmi.o opal-power.o opal-irqchip.o
>   obj-y			+= opal-kmsg.o opal-powercap.o opal-psr.o opal-sensor-groups.o
> +obj-y			+= opal-xscom.o scom.o
>   
>   obj-$(CONFIG_SMP)	+= smp.o subcore.o subcore-asm.o
>   obj-$(CONFIG_PCI)	+= pci.o pci-ioda.o npu-dma.o pci-ioda-tce.o
>   obj-$(CONFIG_CXL_BASE)	+= pci-cxl.o
>   obj-$(CONFIG_EEH)	+= eeh-powernv.o
> -obj-$(CONFIG_PPC_SCOM)	+= opal-xscom.o
>   obj-$(CONFIG_MEMORY_FAILURE)	+= opal-memory-errors.o
>   obj-$(CONFIG_OPAL_PRD)	+= opal-prd.o
>   obj-$(CONFIG_PERF_EVENTS) += opal-imc.o
> diff --git a/arch/powerpc/platforms/powernv/opal-xscom.c b/arch/powerpc/platforms/powernv/opal-xscom.c
> index 22d5e1110dbb..66337d92cb63 100644
> --- a/arch/powerpc/platforms/powernv/opal-xscom.c
> +++ b/arch/powerpc/platforms/powernv/opal-xscom.c
> @@ -18,7 +18,8 @@
>   #include <asm/machdep.h>
>   #include <asm/firmware.h>
>   #include <asm/opal.h>
> -#include <asm/scom.h>
> +
> +#include "scom.h"
>   
>   /*
>    * We could probably fit that inside the scom_map_t
> diff --git a/arch/powerpc/sysdev/scom.c b/arch/powerpc/platforms/powernv/scom.c
> similarity index 99%
> rename from arch/powerpc/sysdev/scom.c
> rename to arch/powerpc/platforms/powernv/scom.c
> index a707b24a7ddb..50c019d2ef45 100644
> --- a/arch/powerpc/sysdev/scom.c
> +++ b/arch/powerpc/platforms/powernv/scom.c
> @@ -23,9 +23,10 @@
>   #include <linux/export.h>
>   #include <asm/debugfs.h>
>   #include <asm/prom.h>
> -#include <asm/scom.h>
>   #include <linux/uaccess.h>
>   
> +#include "scom.h"
> +
>   const struct scom_controller *scom_controller;
>   EXPORT_SYMBOL_GPL(scom_controller);
>   
> diff --git a/arch/powerpc/include/asm/scom.h b/arch/powerpc/platforms/powernv/scom.h
> similarity index 95%
> rename from arch/powerpc/include/asm/scom.h
> rename to arch/powerpc/platforms/powernv/scom.h
> index f5cde45b1161..b14fe0edf95b 100644
> --- a/arch/powerpc/include/asm/scom.h
> +++ b/arch/powerpc/platforms/powernv/scom.h
> @@ -18,12 +18,8 @@
>    *   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
> +#ifndef _SCOM_H
> +#define _SCOM_H
>   
>   /*
>    * The SCOM bus is a sideband bus used for accessing various internal
> @@ -161,7 +157,4 @@ static inline int scom_write(scom_map_t map, u64 reg, u64 value)
>   }
>   
>   
> -#endif /* CONFIG_PPC_SCOM */
> -#endif /* __ASSEMBLY__ */
> -#endif /* __KERNEL__ */
> -#endif /* _ASM_POWERPC_SCOM_H */
> +#endif /* _SCOM_H */
> diff --git a/arch/powerpc/sysdev/Kconfig b/arch/powerpc/sysdev/Kconfig
> index e0dbec780fe9..7808d279ff1d 100644
> --- a/arch/powerpc/sysdev/Kconfig
> +++ b/arch/powerpc/sysdev/Kconfig
> @@ -28,13 +28,6 @@ config PPC_MSI_BITMAP
>   source "arch/powerpc/sysdev/xics/Kconfig"
>   source "arch/powerpc/sysdev/xive/Kconfig"
>   
> -config PPC_SCOM
> -	bool
> -
> -config SCOM_DEBUGFS
> -	bool "Expose SCOM controllers via debugfs"
> -	depends on PPC_SCOM && DEBUG_FS
> -
>   config GE_FPGA
>   	bool
>   
> diff --git a/arch/powerpc/sysdev/Makefile b/arch/powerpc/sysdev/Makefile
> index aaf23283ba0c..35d52d1d2fc0 100644
> --- a/arch/powerpc/sysdev/Makefile
> +++ b/arch/powerpc/sysdev/Makefile
> @@ -51,8 +51,6 @@ ifdef CONFIG_SUSPEND
>   obj-$(CONFIG_PPC_BOOK3S_32)	+= 6xx-suspend.o
>   endif
>   
> -obj-$(CONFIG_PPC_SCOM)		+= scom.o
> -
>   obj-$(CONFIG_PPC_EARLY_DEBUG_MEMCONS)	+= udbg_memcons.o
>   
>   obj-$(CONFIG_PPC_XICS)		+= xics/
> 

-- 
Andrew Donnellan              OzLabs, ADL Canberra
ajd@linux.ibm.com             IBM Australia Limited

Re: [PATCH v2 5/5] powerpc/configs: Disable SCOM_DEBUGFS in powernv_defconfig

[Andrew Donnellan]

On 9/5/19 3:54 pm, Andrew Donnellan wrote:
> On 9/5/19 3:37 pm, Nicholas Piggin wrote:
>> Andrew Donnellan's on May 9, 2019 3:11 pm:
>>> SCOM_DEBUGFS is really not needed for anything other than low-level
>>> hardware debugging.
>>>
>>> opal-prd uses its own interface (/dev/prd) for SCOM access, so it 
>>> doesn't
>>> need SCOM_DEBUGFS.
>>>
>>> At some point in the future we'll introduce a debug config fragment 
>>> where
>>> this can go instead.
>>
>> That doesn't really explain why you want to disable it. It is useful
>> for low level hardware debugging, I added it.
>>
>> obscurity^Wsecurity?
> 
> Mostly just a general feeling that it's not something we need to have by 
> default. Security-wise, PRD still provides SCOM access, though we are 
> going to look at how we can further lock that down. Shrinks the build by 
> only a few kilobytes...
> 
> mpe said he's planning on adding a debug.config where we can shift stuff 
> like this, and if/when we do that I would like to see this moved there, 
> but perhaps this patch can wait until then. I'll let mpe decide.
> 

mpe do you have thoughts on this? I would like to see at least the rest 
of this series merged.


Andrew


> 
> Andrew
> 
> 
>>
>>>
>>> Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
>>> ---
>>> v1->v2:
>>> - new patch
>>> ---
>>>   arch/powerpc/configs/powernv_defconfig | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/arch/powerpc/configs/powernv_defconfig 
>>> b/arch/powerpc/configs/powernv_defconfig
>>> index ef2ef98d3f28..d5a6608cb2e0 100644
>>> --- a/arch/powerpc/configs/powernv_defconfig
>>> +++ b/arch/powerpc/configs/powernv_defconfig
>>> @@ -38,7 +38,7 @@ CONFIG_MODULE_UNLOAD=y
>>>   CONFIG_MODVERSIONS=y
>>>   CONFIG_MODULE_SRCVERSION_ALL=y
>>>   CONFIG_PARTITION_ADVANCED=y
>>> -CONFIG_SCOM_DEBUGFS=y
>>> +# CONFIG_SCOM_DEBUGFS is not set
>>>   CONFIG_OPAL_PRD=y
>>>   CONFIG_PPC_MEMTRACE=y
>>>   # CONFIG_PPC_PSERIES is not set
>>> -- 
>>> 2.20.1
>>>
>>>
>>
> 

-- 
Andrew Donnellan              OzLabs, ADL Canberra
ajd@linux.ibm.com             IBM Australia Limited

Re: [PATCH v2 1/5] powerpc/powernv: Move SCOM access code into powernv platform

[Michael Ellerman]

Andrew Donnellan <ajd@linux.ibm.com> writes:
> On 9/5/19 3:11 pm, Andrew Donnellan wrote:
>> The powernv platform is the only one that directly accesses SCOMs. Move the
>> support code to platforms/powernv, and get rid of the PPC_SCOM Kconfig
>> option, as SCOM support is always selected when compiling for powernv.
>> 
>> This also means that the Kconfig item for CONFIG_SCOM_DEBUGFS will actually
>> show up in menuconfig, as previously it was the only labelled option in
>> sysdev/Kconfig and wasn't actually in a menu.
>
> As I've just realised, this isn't actually correct - the option does 
> indeed show up... in the root menu, where I've just been trained to 
> ignore it, and where you won't get a menu location if you try to search 
> for it using / in menuconfig.
>
> I think moving it to the platform menu is obviously a better location. 
> mpe would you be able to fix up the commit message in merge?

Yes, done.

cheers

Re: [PATCH v2 5/5] powerpc/configs: Disable SCOM_DEBUGFS in powernv_defconfig

[Michael Ellerman]

Andrew Donnellan <ajd@linux.ibm.com> writes:
> On 9/5/19 3:54 pm, Andrew Donnellan wrote:
>> On 9/5/19 3:37 pm, Nicholas Piggin wrote:
>>> Andrew Donnellan's on May 9, 2019 3:11 pm:
>>>> SCOM_DEBUGFS is really not needed for anything other than low-level
>>>> hardware debugging.
>>>>
>>>> opal-prd uses its own interface (/dev/prd) for SCOM access, so it 
>>>> doesn't
>>>> need SCOM_DEBUGFS.
>>>>
>>>> At some point in the future we'll introduce a debug config fragment 
>>>> where
>>>> this can go instead.
>>>
>>> That doesn't really explain why you want to disable it. It is useful
>>> for low level hardware debugging, I added it.
>>>
>>> obscurity^Wsecurity?
>> 
>> Mostly just a general feeling that it's not something we need to have by 
>> default. Security-wise, PRD still provides SCOM access, though we are 
>> going to look at how we can further lock that down. Shrinks the build by 
>> only a few kilobytes...
>> 
>> mpe said he's planning on adding a debug.config where we can shift stuff 
>> like this, and if/when we do that I would like to see this moved there, 
>> but perhaps this patch can wait until then. I'll let mpe decide.
>
> mpe do you have thoughts on this? I would like to see at least the rest 
> of this series merged.

I think it should be off by default, it may be true that root can
attack/break the system in many other ways, but providing unrestricted
SCOM access is a pretty big opening.

This is similar to strict /dev/mem IMO, which "everyone" agrees is a
good idea these days.

It's pretty trivial for folks doing development to turn it on in their
local trees, and I would also welcome a debug.config fragment that
enables it.

So I'll take the whole series.

cheers

Re: [PATCH v2 1/5] powerpc/powernv: Move SCOM access code into powernv platform

[Michael Ellerman]

On Thu, 2019-05-09 at 05:11:15 UTC, Andrew Donnellan wrote:
> The powernv platform is the only one that directly accesses SCOMs. Move the
> support code to platforms/powernv, and get rid of the PPC_SCOM Kconfig
> option, as SCOM support is always selected when compiling for powernv.
> 
> This also means that the Kconfig item for CONFIG_SCOM_DEBUGFS will actually
> show up in menuconfig, as previously it was the only labelled option in
> sysdev/Kconfig and wasn't actually in a menu.
> 
> Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>

Series applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/08a456aa643776757e07adfdebe7f7681117d144

cheers