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[RFC v6 00/25] Re-use nvram module

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  [RFC v6 00/25] Re-use nvram module Finn Thain <fthain@telegraphics.com.au> - 2015-08-23 13:20 +0200
    [RFC v6 24/25] m68k/mac: Fix PRAM accessors Finn Thain <fthain@telegraphics.com.au> - 2015-08-23 13:20 +0200
    [RFC v6 04/25] char/nvram: Re-order functions to remove forward declarations and #ifdefs Finn Thain <fthain@telegraphics.com.au> - 2015-08-23 13:20 +0200
    [RFC v6 01/25] scsi/atari_scsi: Dont select CONFIG_NVRAM Finn Thain <fthain@telegraphics.com.au> - 2015-08-23 13:20 +0200
    [RFC v6 09/25] char/nvram: Use generic fixed_size_llseek() Finn Thain <fthain@telegraphics.com.au> - 2015-08-23 13:20 +0200
    [RFC v6 08/25] char/nvram: Implement NVRAM read/write methods Finn Thain <fthain@telegraphics.com.au> - 2015-08-23 13:30 +0200
    [RFC v6 05/25] char/nvram: Adopt arch_nvram_ops Finn Thain <fthain@telegraphics.com.au> - 2015-08-23 13:30 +0200
    [RFC v6 06/25] x86/thinkpad_acpi: Use arch_nvram_ops methods instead of nvram_read_byte() and nvram_write_byte() Finn Thain <fthain@telegraphics.com.au> - 2015-08-23 13:30 +0200

#1211598 — [RFC v6 00/25] Re-use nvram module

The generic NVRAM module, drivers/char/generic_nvram, implements a
/dev/nvram misc device. It is used only by 32-bit PowerPC platforms and
isn't generic enough to be more widely used.

The RTC NVRAM module, drivers/char/nvram, also implements a /dev/nvram
misc device. It is used by x86, ARM and m68k.

The former module cannot be used on x86, ARM or m68k because it
cannot co-exist with the latter module, partly due to the Kconfig logic.

It is possible to modify the modules so that one kernel binary could
have either, neither or both. However, automatically loading the
appropriate module is then impossible; if both provide the
char-major-10-144 alias then the wrong module will end up being loaded.
Hence a multi-platform kernel binary needs a single generic nvram module
with alias char-major-10-144.

Therefore, drivers/char/nvram.c should be made more generic and the
arch-specific code therein should be moved to a more appropriate
place under arch/. Also, drivers/char/generic_nvram.c should be removed
to reduce code duplication.

In this patch series, Atari-specific code is moved from the nvram module
to arch/m68k/atari. More arch-specific code in the nvram module could
be moved, probably to arch/x86, but it is difficult to determine just
what code is relevant to ARM platforms and what code is x86-only.

In addressing code duplication, v1 of this patch series removes three
inconsistent /dev/nvram misc device implementations. One of these,
drivers/macintosh/nvram.c is entirely unused already. The other two,
drivers/char/generic_nvram.c and the misc device implementation in
arch/powerpc/kernel/nvram_64.c, are replaced by drivers/char/nvram.c.

A benefit of this work is better consistency -- between PPC32 and PPC64
as well as between PPC_PMAC and MAC. This new uniformity does have
implications for userspace, that is, some error codes for some ioctl calls
become consistent on all PowerPC platforms.

The drivers/char/nvram module becomes sufficiently generic to be useful
to other platforms and architectures, besides those with "CMOS" RTC. At the
end of this patch series the module is adopted by the m68k Mac port, which
already has PRAM access functions but lacks the /dev/nvram misc device.

This patch series has been compile-tested for arm, m68k, powerpc and x86.
The nvram and thinkpad_acpi modules were regression tested on a ThinkPad
T43. The /dev/nvram functionality was also regression tested on a G3
PowerMac. The nvram module was also tested on a PowerBook 520, Quadra 650
and Atari Falcon. AFAIK, no testing has been done on PPC64 as yet.

Changes since v1:
- Minor changes to patches 7, 15 and 20 as described in commit logs.
- Revised patches 21 and 24 to address comments from Geert.

Changes since v2:
- Dropped patch 1, "macintosh/nvram: Remove as unused", because it has
since been merged.
- Inserted a new patch, "m68k/mac: Use macros for RTC accesses not
magic numbers".
- Revised patches 21 and 23 to address comments from Geert.

Changes since v3:
- Split the patch, "m68k/atari: Move Atari-specific code out of
drivers/char/nvram.c", as suggested by Geert.
- Revised patches 11 and 25 to address comments from Geert.
- Minor change to patch 21 as described in commit log.

Changes since v4:
- Split the patch, "powerpc, fbdev: Use arch_nvram_ops methods instead
of nvram_read_byte() and nvram_write_byte()", so as to separately address
inconsistent use of Kconfig symbols in PowerMac fbdev drivers.
- Fix possible git bisect build failure with CONFIG_PPC_PMAC=n.

Changes since v5:
- Dropped patch 2, "char/nvram: Use bitwise OR to obtain Atari video mode
data", since it has been added to Greg Kroah-Hartman's char-misc-next queue.
- In patch 15, error codes from the IOC_NVRAM_GET_OFFSET ioctl are now
consistent with the old generic_nvram module.

---
 arch/m68k/Kconfig                          |    3 
 arch/m68k/Kconfig.machine                  |    2 
 arch/m68k/atari/Makefile                   |    2 
 arch/m68k/atari/nvram.c                    |  291 +++++++++++
 arch/m68k/include/asm/atarihw.h            |    6 
 arch/m68k/include/asm/macintosh.h          |    4 
 arch/m68k/kernel/setup_mm.c                |  100 +++
 arch/m68k/mac/misc.c                       |  207 +++++---
 arch/powerpc/Kconfig                       |    5 
 arch/powerpc/include/asm/nvram.h           |    9 
 arch/powerpc/kernel/nvram_64.c             |  203 +------
 arch/powerpc/kernel/setup_32.c             |   27 -
 arch/powerpc/platforms/chrp/Makefile       |    2 
 arch/powerpc/platforms/chrp/nvram.c        |   14 
 arch/powerpc/platforms/chrp/setup.c        |    2 
 arch/powerpc/platforms/powermac/Makefile   |    5 
 arch/powerpc/platforms/powermac/nvram.c    |    9 
 arch/powerpc/platforms/powermac/setup.c    |    3 
 arch/powerpc/platforms/pseries/nvram.c     |    2 
 drivers/char/Kconfig                       |   13 
 drivers/char/Makefile                      |    6 
 drivers/char/generic_nvram.c               |  174 ------
 drivers/char/nvram.c                       |  742 ++++++++++++-----------------
 drivers/platform/x86/thinkpad_acpi.c       |   20 
 drivers/scsi/Kconfig                       |    6 
 drivers/scsi/atari_scsi.c                  |   16 
 drivers/video/fbdev/Kconfig                |    2 
 drivers/video/fbdev/controlfb.c            |    4 
 drivers/video/fbdev/imsttfb.c              |   17 
 drivers/video/fbdev/matrox/matroxfb_base.c |    6 
 drivers/video/fbdev/platinumfb.c           |    4 
 drivers/video/fbdev/valkyriefb.c           |   18 
 include/linux/nvram.h                      |   23 
 include/uapi/linux/pmu.h                   |    2 
 34 files changed, 998 insertions(+), 951 deletions(-)




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#1211599 — [RFC v6 24/25] m68k/mac: Fix PRAM accessors

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>

---

Tested on a PowerBook 520 and Quadra 650.

Changes since v2:
- Make use of the RTC_* macros from the previous patch and add a few more
besides.

---
 arch/m68k/mac/misc.c     |   39 +++++++++++++++++++++++++++++++++------
 include/uapi/linux/pmu.h |    2 ++
 2 files changed, 35 insertions(+), 6 deletions(-)

Index: linux/arch/m68k/mac/misc.c
===================================================================
--- linux.orig/arch/m68k/mac/misc.c	2015-08-23 20:41:23.000000000 +1000
+++ linux/arch/m68k/mac/misc.c	2015-08-23 20:41:25.000000000 +1000
@@ -119,19 +119,22 @@ static void pmu_write_time(long data)
 static unsigned char pmu_pram_read_byte(int offset)
 {
 	struct adb_request req;
-	if (pmu_request(&req, NULL, 3, PMU_READ_NVRAM,
-			(offset >> 8) & 0xFF, offset & 0xFF) < 0)
+
+	if (pmu_request(&req, NULL, 3, PMU_READ_XPRAM,
+	                offset & 0xFF, 1) < 0)
 		return 0;
 	while (!req.complete)
 		pmu_poll();
-	return req.reply[3];
+
+	return req.reply[1];
 }
 
 static void pmu_pram_write_byte(unsigned char data, int offset)
 {
 	struct adb_request req;
-	if (pmu_request(&req, NULL, 4, PMU_WRITE_NVRAM,
-			(offset >> 8) & 0xFF, offset & 0xFF, data) < 0)
+
+	if (pmu_request(&req, NULL, 4, PMU_WRITE_XPRAM,
+	                offset & 0xFF, 1, data) < 0)
 		return;
 	while (!req.complete)
 		pmu_poll();
@@ -257,6 +260,16 @@ static void via_rtc_send(__u8 data)
 #define RTC_REG_WRITE_PROTECT   13
 
 /*
+ * Inside Mac has no information about two-byte RTC commands but
+ * the MESS source code has the essentials.
+ */
+
+#define RTC_REG_XPRAM           14
+#define RTC_CMD_XPRAM_READ      (RTC_CMD_READ(RTC_REG_XPRAM) << 8)
+#define RTC_CMD_XPRAM_WRITE     (RTC_CMD_WRITE(RTC_REG_XPRAM) << 8)
+#define RTC_CMD_XPRAM_ARG(a)    (((a & 0xE0) << 3) | ((a & 0x1F) << 2))
+
+/*
  * Execute a VIA PRAM/RTC command. For read commands
  * data should point to a one-byte buffer for the
  * resulting data. For write commands it should point
@@ -303,11 +316,25 @@ static void via_rtc_command(int command,
 
 static unsigned char via_pram_read_byte(int offset)
 {
-	return 0;
+	unsigned char temp;
+
+	via_rtc_command(RTC_CMD_XPRAM_READ | RTC_CMD_XPRAM_ARG(offset), &temp);
+
+	return temp;
 }
 
 static void via_pram_write_byte(unsigned char data, int offset)
 {
+	unsigned char temp;
+
+	temp = 0x55;
+	via_rtc_command(RTC_CMD_WRITE(RTC_REG_WRITE_PROTECT), &temp);
+
+	temp = data;
+	via_rtc_command(RTC_CMD_XPRAM_WRITE | RTC_CMD_XPRAM_ARG(offset), &temp);
+
+	temp = 0x55 | RTC_FLG_WRITE_PROTECT;
+	via_rtc_command(RTC_CMD_WRITE(RTC_REG_WRITE_PROTECT), &temp);
 }
 
 /*
Index: linux/include/uapi/linux/pmu.h
===================================================================
--- linux.orig/include/uapi/linux/pmu.h	2015-08-23 20:40:53.000000000 +1000
+++ linux/include/uapi/linux/pmu.h	2015-08-23 20:41:25.000000000 +1000
@@ -18,7 +18,9 @@
 #define PMU_POWER_CTRL		0x11	/* control power of some devices */
 #define PMU_ADB_CMD		0x20	/* send ADB packet */
 #define PMU_ADB_POLL_OFF	0x21	/* disable ADB auto-poll */
+#define PMU_WRITE_XPRAM		0x32	/* write eXtended Parameter RAM */
 #define PMU_WRITE_NVRAM		0x33	/* write non-volatile RAM */
+#define PMU_READ_XPRAM		0x3a	/* read eXtended Parameter RAM */
 #define PMU_READ_NVRAM		0x3b	/* read non-volatile RAM */
 #define PMU_SET_RTC		0x30	/* set real-time clock */
 #define PMU_READ_RTC		0x38	/* read real-time clock */


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#1211600 — [RFC v6 04/25] char/nvram: Re-order functions to remove forward declarations and #ifdefs

Also give functions more sensible names: nvram_misc_* for misc device ops,
nvram_proc_* for proc file ops and nvram_module_* for init and exit
functions. This makes them distict from nvram_ops members.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>

---
 drivers/char/nvram.c |  194 ++++++++++++++++++++++-----------------------------
 1 file changed, 86 insertions(+), 108 deletions(-)

Index: linux/drivers/char/nvram.c
===================================================================
--- linux.orig/drivers/char/nvram.c	2015-08-23 20:40:55.000000000 +1000
+++ linux/drivers/char/nvram.c	2015-08-23 20:40:58.000000000 +1000
@@ -54,11 +54,6 @@ static int nvram_open_mode;	/* special o
 #define NVRAM_WRITE		1 /* opened for writing (exclusive) */
 #define NVRAM_EXCL		2 /* opened with O_EXCL */
 
-#ifdef CONFIG_PROC_FS
-static void pc_nvram_proc_read(unsigned char *contents, struct seq_file *seq,
-                               void *offset);
-#endif
-
 /*
  * These functions are provided to be called internally or by other parts of
  * the kernel. It's up to the caller to ensure correct checksum before reading
@@ -170,7 +165,7 @@ void nvram_set_checksum(void)
  * The are the file operation function for user access to /dev/nvram
  */
 
-static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
+static loff_t nvram_misc_llseek(struct file *file, loff_t offset, int origin)
 {
 	switch (origin) {
 	case 0:
@@ -189,8 +184,8 @@ static loff_t nvram_llseek(struct file *
 	return (offset >= 0) ? (file->f_pos = offset) : -EINVAL;
 }
 
-static ssize_t nvram_read(struct file *file, char __user *buf,
-						size_t count, loff_t *ppos)
+static ssize_t nvram_misc_read(struct file *file, char __user *buf,
+                               size_t count, loff_t *ppos)
 {
 	unsigned char contents[NVRAM_BYTES];
 	unsigned i = *ppos;
@@ -218,8 +213,8 @@ checksum_err:
 	return -EIO;
 }
 
-static ssize_t nvram_write(struct file *file, const char __user *buf,
-						size_t count, loff_t *ppos)
+static ssize_t nvram_misc_write(struct file *file, const char __user *buf,
+                                size_t count, loff_t *ppos)
 {
 	unsigned char contents[NVRAM_BYTES];
 	unsigned i = *ppos;
@@ -257,8 +252,8 @@ checksum_err:
 	return -EIO;
 }
 
-static long nvram_ioctl(struct file *file, unsigned int cmd,
-			unsigned long arg)
+static long nvram_misc_ioctl(struct file *file, unsigned int cmd,
+                             unsigned long arg)
 {
 	int i;
 
@@ -298,7 +293,7 @@ static long nvram_ioctl(struct file *fil
 	}
 }
 
-static int nvram_open(struct inode *inode, struct file *file)
+static int nvram_misc_open(struct inode *inode, struct file *file)
 {
 	spin_lock(&nvram_state_lock);
 
@@ -320,7 +315,7 @@ static int nvram_open(struct inode *inod
 	return 0;
 }
 
-static int nvram_release(struct inode *inode, struct file *file)
+static int nvram_misc_release(struct inode *inode, struct file *file)
 {
 	spin_lock(&nvram_state_lock);
 
@@ -337,100 +332,6 @@ static int nvram_release(struct inode *i
 	return 0;
 }
 
-#ifndef CONFIG_PROC_FS
-static int nvram_add_proc_fs(void)
-{
-	return 0;
-}
-
-#else
-
-static int nvram_proc_read(struct seq_file *seq, void *offset)
-{
-	unsigned char contents[NVRAM_BYTES];
-	int i = 0;
-
-	spin_lock_irq(&rtc_lock);
-	for (i = 0; i < NVRAM_BYTES; ++i)
-		contents[i] = __nvram_read_byte(i);
-	spin_unlock_irq(&rtc_lock);
-
-	pc_nvram_proc_read(contents, seq, offset);
-
-	return 0;
-}
-
-static int nvram_proc_open(struct inode *inode, struct file *file)
-{
-	return single_open(file, nvram_proc_read, NULL);
-}
-
-static const struct file_operations nvram_proc_fops = {
-	.owner		= THIS_MODULE,
-	.open		= nvram_proc_open,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= single_release,
-};
-
-static int nvram_add_proc_fs(void)
-{
-	if (!proc_create("driver/nvram", 0, NULL, &nvram_proc_fops))
-		return -ENOMEM;
-	return 0;
-}
-
-#endif /* CONFIG_PROC_FS */
-
-static const struct file_operations nvram_fops = {
-	.owner		= THIS_MODULE,
-	.llseek		= nvram_llseek,
-	.read		= nvram_read,
-	.write		= nvram_write,
-	.unlocked_ioctl	= nvram_ioctl,
-	.open		= nvram_open,
-	.release	= nvram_release,
-};
-
-static struct miscdevice nvram_dev = {
-	NVRAM_MINOR,
-	"nvram",
-	&nvram_fops
-};
-
-static int __init nvram_init(void)
-{
-	int ret;
-
-	ret = misc_register(&nvram_dev);
-	if (ret) {
-		printk(KERN_ERR "nvram: can't misc_register on minor=%d\n",
-		    NVRAM_MINOR);
-		goto out;
-	}
-	ret = nvram_add_proc_fs();
-	if (ret) {
-		printk(KERN_ERR "nvram: can't create /proc/driver/nvram\n");
-		goto outmisc;
-	}
-	ret = 0;
-	printk(KERN_INFO "Non-volatile memory driver v" NVRAM_VERSION "\n");
-out:
-	return ret;
-outmisc:
-	misc_deregister(&nvram_dev);
-	goto out;
-}
-
-static void __exit nvram_cleanup_module(void)
-{
-	remove_proc_entry("driver/nvram", NULL);
-	misc_deregister(&nvram_dev);
-}
-
-module_init(nvram_init);
-module_exit(nvram_cleanup_module);
-
 #ifdef CONFIG_PROC_FS
 
 static char *floppy_types[] = {
@@ -508,7 +409,84 @@ static void pc_nvram_proc_read(unsigned
 	return;
 }
 
+static int nvram_proc_read(struct seq_file *seq, void *offset)
+{
+	unsigned char contents[NVRAM_BYTES];
+	int i = 0;
+
+	spin_lock_irq(&rtc_lock);
+	for (i = 0; i < NVRAM_BYTES; ++i)
+		contents[i] = __nvram_read_byte(i);
+	spin_unlock_irq(&rtc_lock);
+
+	pc_nvram_proc_read(contents, seq, offset);
+
+	return 0;
+}
+
+static int nvram_proc_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, nvram_proc_read, NULL);
+}
+
+static const struct file_operations nvram_proc_fops = {
+	.owner		= THIS_MODULE,
+	.open		= nvram_proc_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
 #endif /* CONFIG_PROC_FS */
 
+static const struct file_operations nvram_misc_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= nvram_misc_llseek,
+	.read		= nvram_misc_read,
+	.write		= nvram_misc_write,
+	.unlocked_ioctl	= nvram_misc_ioctl,
+	.open		= nvram_misc_open,
+	.release	= nvram_misc_release,
+};
+
+static struct miscdevice nvram_misc = {
+	NVRAM_MINOR,
+	"nvram",
+	&nvram_misc_fops,
+};
+
+static int __init nvram_module_init(void)
+{
+	int ret;
+
+	ret = misc_register(&nvram_misc);
+	if (ret) {
+		pr_err("nvram: can't misc_register on minor=%d\n", NVRAM_MINOR);
+		return ret;
+	}
+
+#ifdef CONFIG_PROC_FS
+	if (!proc_create("driver/nvram", 0, NULL, &nvram_proc_fops)) {
+		pr_err("nvram: can't create /proc/driver/nvram\n");
+		misc_deregister(&nvram_misc);
+		return -ENOMEM;
+	}
+#endif
+
+	pr_info("Non-volatile memory driver v" NVRAM_VERSION "\n");
+	return 0;
+}
+
+static void __exit nvram_module_exit(void)
+{
+#ifdef CONFIG_PROC_FS
+	remove_proc_entry("driver/nvram", NULL);
+#endif
+	misc_deregister(&nvram_misc);
+}
+
+module_init(nvram_module_init);
+module_exit(nvram_module_exit);
+
 MODULE_LICENSE("GPL");
 MODULE_ALIAS_MISCDEV(NVRAM_MINOR);


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#1211601 — [RFC v6 01/25] scsi/atari_scsi: Dont select CONFIG_NVRAM

On powerpc, setting CONFIG_NVRAM=n builds a kernel with no NVRAM support.
Setting CONFIG_NVRAM=m enables the /dev/nvram misc device module without
enabling NVRAM support in drivers. Setting CONFIG_NVRAM=y enables the
misc device (built-in) and also enables NVRAM support in drivers.

m68k shares the valkyriefb driver with powerpc, and since that driver uses
NVRAM, it is affected by CONFIG_ATARI_SCSI, because of the use of
"select NVRAM".

Adopt the powerpc convention on m68k to avoid surprises.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Christian T. Steigies <cts@debian.org>

---

This patch temporarily disables CONFIG_NVRAM on Atari, to prevent build
failures when bisecting the rest of this patch series. It gets enabled
again with the introduction of CONFIG_HAVE_ARCH_NVRAM_OPS, once the
nvram_* global functions have been moved to an ops struct.

The removal of "select NVRAM" may mean that some kernel configs (such
as Debian/m68k) may need tweaking.

---
 drivers/char/Kconfig      |    5 +----
 drivers/scsi/Kconfig      |    6 +++---
 drivers/scsi/atari_scsi.c |    8 ++++----
 3 files changed, 8 insertions(+), 11 deletions(-)

Index: linux/drivers/char/Kconfig
===================================================================
--- linux.orig/drivers/char/Kconfig	2015-08-23 20:40:53.000000000 +1000
+++ linux/drivers/char/Kconfig	2015-08-23 20:40:53.000000000 +1000
@@ -247,7 +247,7 @@ source "drivers/char/hw_random/Kconfig"
 
 config NVRAM
 	tristate "/dev/nvram support"
-	depends on ATARI || X86 || (ARM && RTC_DRV_CMOS) || GENERIC_NVRAM
+	depends on X86 || (ARM && RTC_DRV_CMOS) || GENERIC_NVRAM
 	---help---
 	  If you say Y here and create a character special file /dev/nvram
 	  with major number 10 and minor number 144 using mknod ("man mknod"),
@@ -265,9 +265,6 @@ config NVRAM
 	  should NEVER idly tamper with it. See Ralf Brown's interrupt list
 	  for a guide to the use of CMOS bytes by your BIOS.
 
-	  On Atari machines, /dev/nvram is always configured and does not need
-	  to be selected.
-
 	  To compile this driver as a module, choose M here: the
 	  module will be called nvram.
 
Index: linux/drivers/scsi/Kconfig
===================================================================
--- linux.orig/drivers/scsi/Kconfig	2015-08-23 20:40:53.000000000 +1000
+++ linux/drivers/scsi/Kconfig	2015-08-23 20:40:53.000000000 +1000
@@ -1609,14 +1609,14 @@ config ATARI_SCSI
 	tristate "Atari native SCSI support"
 	depends on ATARI && SCSI
 	select SCSI_SPI_ATTRS
-	select NVRAM
 	---help---
 	  If you have an Atari with built-in NCR5380 SCSI controller (TT,
 	  Falcon, ...) say Y to get it supported. Of course also, if you have
 	  a compatible SCSI controller (e.g. for Medusa).
 
-	  To compile this driver as a module, choose M here: the
-	  module will be called atari_scsi.
+	  To compile this driver as a module, choose M here: the module will
+	  be called atari_scsi. If you also enable NVRAM support, the SCSI
+	  host's ID is taken from the setting in TT RTC NVRAM.
 
 	  This driver supports both styles of NCR integration into the
 	  system: the TT style (separate DMA), and the Falcon style (via
Index: linux/drivers/scsi/atari_scsi.c
===================================================================
--- linux.orig/drivers/scsi/atari_scsi.c	2015-08-23 20:40:53.000000000 +1000
+++ linux/drivers/scsi/atari_scsi.c	2015-08-23 20:40:53.000000000 +1000
@@ -875,9 +875,10 @@ static int __init atari_scsi_probe(struc
 	if (ATARIHW_PRESENT(TT_SCSI) && setup_sg_tablesize >= 0)
 		atari_scsi_template.sg_tablesize = setup_sg_tablesize;
 
-	if (setup_hostid >= 0) {
+	if (setup_hostid >= 0)
 		atari_scsi_template.this_id = setup_hostid & 7;
-	} else {
+#ifdef CONFIG_NVRAM
+	else
 		/* Test if a host id is set in the NVRam */
 		if (ATARIHW_PRESENT(TT_CLK) && nvram_check_checksum()) {
 			unsigned char b = nvram_read_byte(14);
@@ -888,8 +889,7 @@ static int __init atari_scsi_probe(struc
 			if (b & 0x80)
 				atari_scsi_template.this_id = b & 7;
 		}
-	}
-
+#endif
 
 #ifdef REAL_DMA
 	/* If running on a Falcon and if there's TT-Ram (i.e., more than one


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#1211602 — [RFC v6 09/25] char/nvram: Use generic fixed_size_llseek()

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>

---
 drivers/char/nvram.c |   16 +---------------
 1 file changed, 1 insertion(+), 15 deletions(-)

Index: linux/drivers/char/nvram.c
===================================================================
--- linux.orig/drivers/char/nvram.c	2015-08-23 20:41:03.000000000 +1000
+++ linux/drivers/char/nvram.c	2015-08-23 20:41:04.000000000 +1000
@@ -235,21 +235,7 @@ EXPORT_SYMBOL(arch_nvram_ops);
 
 static loff_t nvram_misc_llseek(struct file *file, loff_t offset, int origin)
 {
-	switch (origin) {
-	case 0:
-		/* nothing to do */
-		break;
-	case 1:
-		offset += file->f_pos;
-		break;
-	case 2:
-		offset += NVRAM_BYTES;
-		break;
-	default:
-		return -EINVAL;
-	}
-
-	return (offset >= 0) ? (file->f_pos = offset) : -EINVAL;
+	return fixed_size_llseek(file, offset, origin, nvram_size);
 }
 
 static ssize_t nvram_misc_read(struct file *file, char __user *buf,


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#1211603 — [RFC v6 08/25] char/nvram: Implement NVRAM read/write methods

Refactor the RTC "CMOS" NVRAM functions so that they can be used as
arch_nvram_ops methods. Checksumming logic is moved from the misc device
operations to the nvram read/write operations.

This makes the misc device implementation more generic. This also
preserves the locking semantics such that "read if checksum valid" and
"write and update checksum" remain atomic operations.

PPC64 implements byte-range read/write methods which are similar to
file_operations struct methods. Other platforms provide only
byte-at-a-time functions. So the misc device prefers the former but
will fall back on the latter.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>

---
 drivers/char/nvram.c |  162 +++++++++++++++++++++++++++++++++++----------------
 1 file changed, 114 insertions(+), 48 deletions(-)

Index: linux/drivers/char/nvram.c
===================================================================
--- linux.orig/drivers/char/nvram.c	2015-08-23 20:41:02.000000000 +1000
+++ linux/drivers/char/nvram.c	2015-08-23 20:41:03.000000000 +1000
@@ -41,6 +41,7 @@
 #include <linux/init.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
+#include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/io.h>
 #include <linux/uaccess.h>
@@ -178,9 +179,48 @@ static ssize_t nvram_get_size(void)
 	return NVRAM_BYTES;
 }
 
+static ssize_t nvram_read(char *buf, size_t count, loff_t *ppos)
+{
+	char *p = buf;
+	loff_t i;
+
+	spin_lock_irq(&rtc_lock);
+	if (!__nvram_check_checksum()) {
+		spin_unlock_irq(&rtc_lock);
+		return -EIO;
+	}
+	for (i = *ppos; count > 0 && i < NVRAM_BYTES; --count, ++i, ++p)
+		*p = __nvram_read_byte(i);
+	spin_unlock_irq(&rtc_lock);
+
+	*ppos = i;
+	return p - buf;
+}
+
+static ssize_t nvram_write(char *buf, size_t count, loff_t *ppos)
+{
+	char *p = buf;
+	loff_t i;
+
+	spin_lock_irq(&rtc_lock);
+	if (!__nvram_check_checksum()) {
+		spin_unlock_irq(&rtc_lock);
+		return -EIO;
+	}
+	for (i = *ppos; count > 0 && i < NVRAM_BYTES; --count, ++i, ++p)
+		__nvram_write_byte(*p, i);
+	__nvram_set_checksum();
+	spin_unlock_irq(&rtc_lock);
+
+	*ppos = i;
+	return p - buf;
+}
+
 const struct nvram_ops arch_nvram_ops = {
 	.read_byte      = nvram_read_byte,
 	.write_byte     = nvram_write_byte,
+	.read           = nvram_read,
+	.write          = nvram_write,
 	.get_size       = nvram_get_size,
 	.set_checksum   = nvram_set_checksum,
 	.initialize     = nvram_initialize,
@@ -215,69 +255,95 @@ static loff_t nvram_misc_llseek(struct f
 static ssize_t nvram_misc_read(struct file *file, char __user *buf,
                                size_t count, loff_t *ppos)
 {
-	unsigned char contents[NVRAM_BYTES];
-	unsigned i = *ppos;
-	unsigned char *tmp;
-
-	spin_lock_irq(&rtc_lock);
+	loff_t i;
+	char __user *p = buf;
 
-	if (!__nvram_check_checksum())
-		goto checksum_err;
-
-	for (tmp = contents; count-- > 0 && i < NVRAM_BYTES; ++i, ++tmp)
-		*tmp = __nvram_read_byte(i);
-
-	spin_unlock_irq(&rtc_lock);
-
-	if (copy_to_user(buf, contents, tmp - contents))
+	if (!access_ok(VERIFY_WRITE, buf, count))
 		return -EFAULT;
+	if (*ppos >= nvram_size)
+		return 0;
 
-	*ppos = i;
-
-	return tmp - contents;
+	/* If the arch provided a byte range read op, use it. Otherwise
+	 * fall back on the byte-at-a-time accessor.
+	 */
+	if (arch_nvram_ops.read != NULL) {
+		char *tmp;
+		ssize_t ret;
+
+		count = min_t(size_t, count, nvram_size - *ppos);
+		count = min_t(size_t, count, PAGE_SIZE);
+
+		tmp = kmalloc(count, GFP_KERNEL);
+		if (!tmp)
+			return -ENOMEM;
+
+		ret = arch_nvram_ops.read(tmp, count, ppos);
+		if (ret <= 0)
+			goto out;
+
+		if (copy_to_user(buf, tmp, ret)) {
+			*ppos -= ret;
+			ret = -EFAULT;
+		}
+
+out:
+		kfree(tmp);
+		return ret;
+	}
 
-checksum_err:
-	spin_unlock_irq(&rtc_lock);
-	return -EIO;
+	for (i = *ppos; count > 0 && i < nvram_size; ++i, ++p, --count)
+		if (__put_user(arch_nvram_ops.read_byte(i), p))
+			return -EFAULT;
+	*ppos = i;
+	return p - buf;
 }
 
 static ssize_t nvram_misc_write(struct file *file, const char __user *buf,
                                 size_t count, loff_t *ppos)
 {
-	unsigned char contents[NVRAM_BYTES];
-	unsigned i = *ppos;
-	unsigned char *tmp;
-
-	if (i >= NVRAM_BYTES)
-		return 0;	/* Past EOF */
-
-	if (count > NVRAM_BYTES - i)
-		count = NVRAM_BYTES - i;
-	if (count > NVRAM_BYTES)
-		return -EFAULT;	/* Can't happen, but prove it to gcc */
+	loff_t i;
+	const char __user *p = buf;
 
-	if (copy_from_user(contents, buf, count))
+	if (!access_ok(VERIFY_READ, buf, count))
 		return -EFAULT;
+	if (*ppos >= nvram_size)
+		return 0;
 
-	spin_lock_irq(&rtc_lock);
-
-	if (!__nvram_check_checksum())
-		goto checksum_err;
-
-	for (tmp = contents; count--; ++i, ++tmp)
-		__nvram_write_byte(*tmp, i);
-
-	__nvram_set_checksum();
+	/* If the arch provided a byte range write op, use it. Otherwise
+	 * fall back on the byte-at-a-time accessor.
+	 */
+	if (arch_nvram_ops.write != NULL) {
+		char *tmp;
+		ssize_t ret;
+
+		count = min_t(size_t, count, nvram_size - *ppos);
+		count = min_t(size_t, count, PAGE_SIZE);
+
+		tmp = kmalloc(count, GFP_KERNEL);
+		if (!tmp)
+			return -ENOMEM;
+
+		if (copy_from_user(tmp, buf, count)) {
+			ret = -EFAULT;
+			goto out;
+		}
+
+		ret = arch_nvram_ops.write(tmp, count, ppos);
+
+out:
+		kfree(tmp);
+		return ret;
+	}
 
-	spin_unlock_irq(&rtc_lock);
+	for (i = *ppos; count > 0 && i < nvram_size; ++i, ++p, --count) {
+		char c;
 
+		if (__get_user(c, p))
+			return -EFAULT;
+		arch_nvram_ops.write_byte(c, i);
+	}
 	*ppos = i;
-
-	return tmp - contents;
-
-checksum_err:
-	spin_unlock_irq(&rtc_lock);
-	return -EIO;
+	return p - buf;
 }
 
 static long nvram_misc_ioctl(struct file *file, unsigned int cmd,


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#1211605 — [RFC v6 05/25] char/nvram: Adopt arch_nvram_ops

Different platforms and architectures offer different NVRAM sizes and
access methods. E.g. PPC32 has byte-at-a-time read/write functions whereas
PPC64 has byte-range read/write functions. Adopt the nvram_ops struct so
the nvram module can call such functions as are defined by the various 
platforms and architectures.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>

---

The #ifdefs here restrict the procfs and checksumming code to those
architectures with PC-style RTC NVRAM. There may be a better place for
that code but it's an open question. See https://lkml.org/lkml/2015/2/3/22

The procfs code here, unless relevant to an ARM platform, could be moved to
arch/x86 (like the earlier patch does for m68k code) and the nvram ops
could be implemented and exported by the rtc-cmos driver instead. This
would eliminate these #ifdefs and almost eliminate the arch-specific code.

---
 drivers/char/nvram.c  |   30 +++++++++++++++++++++++++++---
 include/linux/nvram.h |    2 ++
 2 files changed, 29 insertions(+), 3 deletions(-)

Index: linux/drivers/char/nvram.c
===================================================================
--- linux.orig/drivers/char/nvram.c	2015-08-23 20:40:58.000000000 +1000
+++ linux/drivers/char/nvram.c	2015-08-23 20:40:59.000000000 +1000
@@ -51,9 +51,12 @@ static DEFINE_MUTEX(nvram_mutex);
 static DEFINE_SPINLOCK(nvram_state_lock);
 static int nvram_open_cnt;	/* #times opened */
 static int nvram_open_mode;	/* special open modes */
+static ssize_t nvram_size;
 #define NVRAM_WRITE		1 /* opened for writing (exclusive) */
 #define NVRAM_EXCL		2 /* opened with O_EXCL */
 
+#if defined(CONFIG_X86) || defined(CONFIG_ARM)
+
 /*
  * These functions are provided to be called internally or by other parts of
  * the kernel. It's up to the caller to ensure correct checksum before reading
@@ -161,6 +164,20 @@ void nvram_set_checksum(void)
 }
 #endif  /*  0  */
 
+static ssize_t nvram_get_size(void)
+{
+	return NVRAM_BYTES;
+}
+
+const struct nvram_ops arch_nvram_ops = {
+	.read_byte      = nvram_read_byte,
+	.write_byte     = nvram_write_byte,
+	.get_size       = nvram_get_size,
+};
+EXPORT_SYMBOL(arch_nvram_ops);
+
+#endif /* CONFIG_X86 || CONFIG_ARM */
+
 /*
  * The are the file operation function for user access to /dev/nvram
  */
@@ -332,7 +349,7 @@ static int nvram_misc_release(struct ino
 	return 0;
 }
 
-#ifdef CONFIG_PROC_FS
+#if defined(CONFIG_PROC_FS) && (defined(CONFIG_X86) || defined(CONFIG_ARM))
 
 static char *floppy_types[] = {
 	"none", "5.25'' 360k", "5.25'' 1.2M", "3.5'' 720k", "3.5'' 1.44M",
@@ -459,13 +476,20 @@ static int __init nvram_module_init(void
 {
 	int ret;
 
+	if (arch_nvram_ops.get_size == NULL)
+		return -ENODEV;
+
+	nvram_size = arch_nvram_ops.get_size();
+	if (nvram_size < 0)
+		return nvram_size;
+
 	ret = misc_register(&nvram_misc);
 	if (ret) {
 		pr_err("nvram: can't misc_register on minor=%d\n", NVRAM_MINOR);
 		return ret;
 	}
 
-#ifdef CONFIG_PROC_FS
+#if defined(CONFIG_PROC_FS) && (defined(CONFIG_X86) || defined(CONFIG_ARM))
 	if (!proc_create("driver/nvram", 0, NULL, &nvram_proc_fops)) {
 		pr_err("nvram: can't create /proc/driver/nvram\n");
 		misc_deregister(&nvram_misc);
@@ -479,7 +503,7 @@ static int __init nvram_module_init(void
 
 static void __exit nvram_module_exit(void)
 {
-#ifdef CONFIG_PROC_FS
+#if defined(CONFIG_PROC_FS) && (defined(CONFIG_X86) || defined(CONFIG_ARM))
 	remove_proc_entry("driver/nvram", NULL);
 #endif
 	misc_deregister(&nvram_misc);
Index: linux/include/linux/nvram.h
===================================================================
--- linux.orig/include/linux/nvram.h	2015-08-23 20:40:57.000000000 +1000
+++ linux/include/linux/nvram.h	2015-08-23 20:40:59.000000000 +1000
@@ -14,6 +14,8 @@ extern int nvram_check_checksum(void);
 struct nvram_ops {
 	ssize_t         (*read)(char *, size_t, loff_t *);
 	ssize_t         (*write)(char *, size_t, loff_t *);
+	unsigned char   (*read_byte)(int);
+	void            (*write_byte)(unsigned char, int);
 	ssize_t         (*get_size)(void);
 };
 


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#1211606 — [RFC v6 06/25] x86/thinkpad_acpi: Use arch_nvram_ops methods instead of nvram_read_byte() and nvram_write_byte()

Make use of arch_nvram_ops in the thinkpad_acpi driver so that the
nvram_* function exports can be removed.

This patch series was tested on a ThinkPad T43.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Acked-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Reviewed-by: Darren Hart <dvhart@linux.intel.com>

---
 drivers/platform/x86/thinkpad_acpi.c |   20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

Index: linux/drivers/platform/x86/thinkpad_acpi.c
===================================================================
--- linux.orig/drivers/platform/x86/thinkpad_acpi.c	2015-08-23 20:40:53.000000000 +1000
+++ linux/drivers/platform/x86/thinkpad_acpi.c	2015-08-23 20:41:01.000000000 +1000
@@ -2312,30 +2312,30 @@ static void hotkey_read_nvram(struct tp_
 	u8 d;
 
 	if (m & TP_NVRAM_HKEY_GROUP_HK2) {
-		d = nvram_read_byte(TP_NVRAM_ADDR_HK2);
+		d = arch_nvram_ops.read_byte(TP_NVRAM_ADDR_HK2);
 		n->thinkpad_toggle = !!(d & TP_NVRAM_MASK_HKT_THINKPAD);
 		n->zoom_toggle = !!(d & TP_NVRAM_MASK_HKT_ZOOM);
 		n->display_toggle = !!(d & TP_NVRAM_MASK_HKT_DISPLAY);
 		n->hibernate_toggle = !!(d & TP_NVRAM_MASK_HKT_HIBERNATE);
 	}
 	if (m & TP_ACPI_HKEY_THNKLGHT_MASK) {
-		d = nvram_read_byte(TP_NVRAM_ADDR_THINKLIGHT);
+		d = arch_nvram_ops.read_byte(TP_NVRAM_ADDR_THINKLIGHT);
 		n->thinklight_toggle = !!(d & TP_NVRAM_MASK_THINKLIGHT);
 	}
 	if (m & TP_ACPI_HKEY_DISPXPAND_MASK) {
-		d = nvram_read_byte(TP_NVRAM_ADDR_VIDEO);
+		d = arch_nvram_ops.read_byte(TP_NVRAM_ADDR_VIDEO);
 		n->displayexp_toggle =
 				!!(d & TP_NVRAM_MASK_HKT_DISPEXPND);
 	}
 	if (m & TP_NVRAM_HKEY_GROUP_BRIGHTNESS) {
-		d = nvram_read_byte(TP_NVRAM_ADDR_BRIGHTNESS);
+		d = arch_nvram_ops.read_byte(TP_NVRAM_ADDR_BRIGHTNESS);
 		n->brightness_level = (d & TP_NVRAM_MASK_LEVEL_BRIGHTNESS)
 				>> TP_NVRAM_POS_LEVEL_BRIGHTNESS;
 		n->brightness_toggle =
 				!!(d & TP_NVRAM_MASK_HKT_BRIGHTNESS);
 	}
 	if (m & TP_NVRAM_HKEY_GROUP_VOLUME) {
-		d = nvram_read_byte(TP_NVRAM_ADDR_MIXER);
+		d = arch_nvram_ops.read_byte(TP_NVRAM_ADDR_MIXER);
 		n->volume_level = (d & TP_NVRAM_MASK_LEVEL_VOLUME)
 				>> TP_NVRAM_POS_LEVEL_VOLUME;
 		n->mute = !!(d & TP_NVRAM_MASK_MUTE);
@@ -6156,7 +6156,7 @@ static unsigned int tpacpi_brightness_nv
 {
 	u8 lnvram;
 
-	lnvram = (nvram_read_byte(TP_NVRAM_ADDR_BRIGHTNESS)
+	lnvram = (arch_nvram_ops.read_byte(TP_NVRAM_ADDR_BRIGHTNESS)
 		  & TP_NVRAM_MASK_LEVEL_BRIGHTNESS)
 		  >> TP_NVRAM_POS_LEVEL_BRIGHTNESS;
 	lnvram &= bright_maxlvl;
@@ -6181,7 +6181,7 @@ static void tpacpi_brightness_checkpoint
 	if (unlikely(!acpi_ec_read(TP_EC_BACKLIGHT, &lec)))
 		goto unlock;
 	lec &= TP_EC_BACKLIGHT_LVLMSK;
-	b_nvram = nvram_read_byte(TP_NVRAM_ADDR_BRIGHTNESS);
+	b_nvram = arch_nvram_ops.read_byte(TP_NVRAM_ADDR_BRIGHTNESS);
 
 	if (lec != ((b_nvram & TP_NVRAM_MASK_LEVEL_BRIGHTNESS)
 			     >> TP_NVRAM_POS_LEVEL_BRIGHTNESS)) {
@@ -6189,7 +6189,7 @@ static void tpacpi_brightness_checkpoint
 		b_nvram &= ~(TP_NVRAM_MASK_LEVEL_BRIGHTNESS <<
 				TP_NVRAM_POS_LEVEL_BRIGHTNESS);
 		b_nvram |= lec;
-		nvram_write_byte(b_nvram, TP_NVRAM_ADDR_BRIGHTNESS);
+		arch_nvram_ops.write_byte(b_nvram, TP_NVRAM_ADDR_BRIGHTNESS);
 		dbg_printk(TPACPI_DBG_BRGHT,
 			   "updated NVRAM backlight level to %u (0x%02x)\n",
 			   (unsigned int) lec, (unsigned int) b_nvram);
@@ -6797,13 +6797,13 @@ static void tpacpi_volume_checkpoint_nvr
 	if (unlikely(!acpi_ec_read(TP_EC_AUDIO, &lec)))
 		goto unlock;
 	lec &= ec_mask;
-	b_nvram = nvram_read_byte(TP_NVRAM_ADDR_MIXER);
+	b_nvram = arch_nvram_ops.read_byte(TP_NVRAM_ADDR_MIXER);
 
 	if (lec != (b_nvram & ec_mask)) {
 		/* NVRAM needs update */
 		b_nvram &= ~ec_mask;
 		b_nvram |= lec;
-		nvram_write_byte(b_nvram, TP_NVRAM_ADDR_MIXER);
+		arch_nvram_ops.write_byte(b_nvram, TP_NVRAM_ADDR_MIXER);
 		dbg_printk(TPACPI_DBG_MIXER,
 			   "updated NVRAM mixer status to 0x%02x (0x%02x)\n",
 			   (unsigned int) lec, (unsigned int) b_nvram);


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