[PATCH v7 01/26] scsi/atari_scsi: Dont select CONFIG_NVRAM

[PATCH v7 01/26] scsi/atari_scsi: Dont select CONFIG_NVRAM

[Finn Thain]

[-- Attachment #1: atari-nvram-disable --]
[-- Type: text/plain, Size: 4282 bytes --]

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	2015-11-01 21:41:24.000000000 +1100
+++ linux/drivers/char/Kconfig	2015-11-01 21:41:24.000000000 +1100
@@ -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	2015-11-01 21:41:24.000000000 +1100
+++ linux/drivers/scsi/Kconfig	2015-11-01 21:41:24.000000000 +1100
@@ -1610,14 +1610,14 @@ 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	2015-11-01 21:41:24.000000000 +1100
+++ linux/drivers/scsi/atari_scsi.c	2015-11-01 21:41:24.000000000 +1100
@@ -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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[PATCH v7 03/26] m68k/atari: Replace nvram_{read, write}_byte with arch_nvram_ops

[Finn Thain]

[-- Attachment #1: atari_scsi-convert-to-nvram_ops --]
[-- Type: text/plain, Size: 5518 bytes --]

By implementing an arch_nvram_ops struct, any platform can re-use the
drivers/char/nvram module without needing any arch-specific code
in that module. Atari does so here.

Atari has one user of nvram_check_checksum() whereas the other platforms
(i.e. x86 and ARM platforms) have none at all. Replace this
validate-checksum-and-read-byte sequence with the equivalent
rtc_nvram_ops.read() call and remove the now unused functions.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Christian T. Steigies <cts@debian.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>

---

The advantage of the new ops struct over the old global nvram_* functions
is that the misc device module can be shared by different platforms
without requiring every platform to implement every nvram_* function.
E.g. only RTC "CMOS" NVRAMs have a checksum for the entire NVRAM
and only PowerPC platforms have a "sync" ioctl.

---
 arch/m68k/atari/nvram.c   |   89 ++++++++++++++++++++++++++++------------------
 drivers/scsi/atari_scsi.c |    8 ++--
 include/linux/nvram.h     |    9 ++++
 3 files changed, 70 insertions(+), 36 deletions(-)

Index: linux/arch/m68k/atari/nvram.c
===================================================================
--- linux.orig/arch/m68k/atari/nvram.c	2015-11-01 21:41:25.000000000 +1100
+++ linux/arch/m68k/atari/nvram.c	2015-11-01 21:41:27.000000000 +1100
@@ -38,33 +38,12 @@ unsigned char __nvram_read_byte(int i)
 	return CMOS_READ(NVRAM_FIRST_BYTE + i);
 }
 
-unsigned char nvram_read_byte(int i)
-{
-	unsigned long flags;
-	unsigned char c;
-
-	spin_lock_irqsave(&rtc_lock, flags);
-	c = __nvram_read_byte(i);
-	spin_unlock_irqrestore(&rtc_lock, flags);
-	return c;
-}
-EXPORT_SYMBOL(nvram_read_byte);
-
 /* This races nicely with trying to read with checksum checking */
 void __nvram_write_byte(unsigned char c, int i)
 {
 	CMOS_WRITE(c, NVRAM_FIRST_BYTE + i);
 }
 
-void nvram_write_byte(unsigned char c, int i)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&rtc_lock, flags);
-	__nvram_write_byte(c, i);
-	spin_unlock_irqrestore(&rtc_lock, flags);
-}
-
 /* On Ataris, the checksum is over all bytes except the checksum bytes
  * themselves; these are at the very end.
  */
@@ -83,18 +62,6 @@ int __nvram_check_checksum(void)
 	       (__nvram_read_byte(ATARI_CKS_LOC + 1) == (sum & 0xff));
 }
 
-int nvram_check_checksum(void)
-{
-	unsigned long flags;
-	int rv;
-
-	spin_lock_irqsave(&rtc_lock, flags);
-	rv = __nvram_check_checksum();
-	spin_unlock_irqrestore(&rtc_lock, flags);
-	return rv;
-}
-EXPORT_SYMBOL(nvram_check_checksum);
-
 static void __nvram_set_checksum(void)
 {
 	int i;
@@ -106,6 +73,62 @@ static void __nvram_set_checksum(void)
 	__nvram_write_byte(sum, ATARI_CKS_LOC + 1);
 }
 
+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;
+}
+
+static ssize_t nvram_get_size(void)
+{
+	return NVRAM_BYTES;
+}
+
+const struct nvram_ops arch_nvram_ops = {
+	.read           = nvram_read,
+	.write          = nvram_write,
+	.get_size       = nvram_get_size,
+};
+EXPORT_SYMBOL(arch_nvram_ops);
+
 #ifdef CONFIG_PROC_FS
 static struct {
 	unsigned char val;
Index: linux/drivers/scsi/atari_scsi.c
===================================================================
--- linux.orig/drivers/scsi/atari_scsi.c	2015-11-01 21:41:24.000000000 +1100
+++ linux/drivers/scsi/atari_scsi.c	2015-11-01 21:41:27.000000000 +1100
@@ -880,13 +880,15 @@ static int __init atari_scsi_probe(struc
 #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);
+		if (ATARIHW_PRESENT(TT_CLK)) {
+			unsigned char b;
+			loff_t offset = 14;
+			ssize_t count = arch_nvram_ops.read(&b, 1, &offset);
 
 			/* Arbitration enabled? (for TOS)
 			 * If yes, use configured host ID
 			 */
-			if (b & 0x80)
+			if ((count == 1) && (b & 0x80))
 				atari_scsi_template.this_id = b & 7;
 		}
 #endif
Index: linux/include/linux/nvram.h
===================================================================
--- linux.orig/include/linux/nvram.h	2015-11-01 21:41:24.000000000 +1100
+++ linux/include/linux/nvram.h	2015-11-01 21:41:27.000000000 +1100
@@ -10,4 +10,13 @@ extern void __nvram_write_byte(unsigned
 extern void nvram_write_byte(unsigned char c, int i);
 extern int __nvram_check_checksum(void);
 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 *);
+	ssize_t         (*get_size)(void);
+};
+
+extern const struct nvram_ops arch_nvram_ops;
+
 #endif  /* _LINUX_NVRAM_H */


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