m68k: Dispatch nvram_ops calls to Atari or Mac functions

This change “m68k: Dispatch nvram_ops calls to Atari or Mac functions” in Linux kernel is authored by Finn Thain <fthain [at] telegraphics.com.au> on Tue Jan 15 15:18:56 2019 +1100.

m68k: Dispatch nvram_ops calls to Atari or Mac functions

A multi-platform kernel binary has to decide at run-time how to dispatch
the arch_nvram_ops calls. Add a platform-independent arch_nvram_ops
struct for this, to replace the atari-specific one.

Enable CONFIG_HAVE_ARCH_NVRAM_OPS for Macs.

Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This Linux change may have been applied to various maintained Linux releases and you can find Linux releases including commit d3b41b6.

There are 125 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 arch/m68k/Kconfig.machine         |  1 +
 arch/m68k/atari/nvram.c           | 21 +++-------
 arch/m68k/include/asm/atarihw.h   |  6 +++
 arch/m68k/include/asm/macintosh.h |  4 ++
 arch/m68k/kernel/setup_mm.c       | 82 ++++++++++++++++++++++++++++++++++++++-
 arch/m68k/mac/misc.c              | 11 ++++++
 6 files changed, 108 insertions(+), 17 deletions(-)

diff --git a/arch/m68k/Kconfig.machine b/arch/m68k/Kconfig.machine
index ad584e3..c01e103 100644
--- a/arch/m68k/Kconfig.machine
+++ b/arch/m68k/Kconfig.machine
@@ -27,6 +27,7 @@ config MAC
 	bool "Macintosh support"
 	depends on MMU
 	select MMU_MOTOROLA if MMU
+	select HAVE_ARCH_NVRAM_OPS
 	help
 	  This option enables support for the Apple Macintosh series of
 	  computers (yes, there is experimental support now, at least for part
diff --git a/arch/m68k/atari/nvram.c b/arch/m68k/atari/nvram.c
index c347fd2..7000d24 100644
--- a/arch/m68k/atari/nvram.c
+++ b/arch/m68k/atari/nvram.c
@@ -74,7 +74,7 @@ static void __nvram_set_checksum(void)
 	__nvram_write_byte(sum, ATARI_CKS_LOC + 1);
 }
 
-static long atari_nvram_set_checksum(void)
+long atari_nvram_set_checksum(void)
 {
 	spin_lock_irq(&rtc_lock);
 	__nvram_set_checksum();
@@ -82,7 +82,7 @@ static long atari_nvram_set_checksum(void)
 	return 0;
 }
 
-static long atari_nvram_initialize(void)
+long atari_nvram_initialize(void)
 {
 	loff_t i;
 
@@ -94,7 +94,7 @@ static long atari_nvram_initialize(void)
 	return 0;
 }
 
-static ssize_t atari_nvram_read(char *buf, size_t count, loff_t *ppos)
+ssize_t atari_nvram_read(char *buf, size_t count, loff_t *ppos)
 {
 	char *p = buf;
 	loff_t i;
@@ -112,7 +112,7 @@ static ssize_t atari_nvram_read(char *buf, size_t count, loff_t *ppos)
 	return p - buf;
 }
 
-static ssize_t atari_nvram_write(char *buf, size_t count, loff_t *ppos)
+ssize_t atari_nvram_write(char *buf, size_t count, loff_t *ppos)
 {
 	char *p = buf;
 	loff_t i;
@@ -131,22 +131,11 @@ static ssize_t atari_nvram_write(char *buf, size_t count, loff_t *ppos)
 	return p - buf;
 }
 
-static ssize_t atari_nvram_get_size(void)
+ssize_t atari_nvram_get_size(void)
 {
-	if (!MACH_IS_ATARI)
-		return -ENODEV;
 	return NVRAM_BYTES;
 }
 
-const struct nvram_ops arch_nvram_ops = {
-	.read           = atari_nvram_read,
-	.write          = atari_nvram_write,
-	.get_size       = atari_nvram_get_size,
-	.set_checksum   = atari_nvram_set_checksum,
-	.initialize     = atari_nvram_initialize,
-};
-EXPORT_SYMBOL(arch_nvram_ops);
-
 #ifdef CONFIG_PROC_FS
 static struct {
 	unsigned char val;
diff --git a/arch/m68k/include/asm/atarihw.h b/arch/m68k/include/asm/atarihw.h
index 9000b24..5330082 100644
--- a/arch/m68k/include/asm/atarihw.h
+++ b/arch/m68k/include/asm/atarihw.h
@@ -33,6 +33,12 @@
 
 extern int atari_SCC_reset_done;
 
+extern ssize_t atari_nvram_read(char *, size_t, loff_t *);
+extern ssize_t atari_nvram_write(char *, size_t, loff_t *);
+extern ssize_t atari_nvram_get_size(void);
+extern long atari_nvram_set_checksum(void);
+extern long atari_nvram_initialize(void);
+
 /* convenience macros for testing machine type */
 #define MACH_IS_ST	((atari_mch_cookie >> 16) == ATARI_MCH_ST)
 #define MACH_IS_STE	((atari_mch_cookie >> 16) == ATARI_MCH_STE && 
diff --git a/arch/m68k/include/asm/macintosh.h b/arch/m68k/include/asm/macintosh.h
index 08cee11..d9a08be 100644
--- a/arch/m68k/include/asm/macintosh.h
+++ b/arch/m68k/include/asm/macintosh.h
@@ -19,6 +19,10 @@
 extern void mac_irq_enable(struct irq_data *data);
 extern void mac_irq_disable(struct irq_data *data);
 
+extern unsigned char mac_pram_read_byte(int);
+extern void mac_pram_write_byte(unsigned char, int);
+extern ssize_t mac_pram_get_size(void);
+
 /*
  *	Macintosh Table
  */
diff --git a/arch/m68k/kernel/setup_mm.c b/arch/m68k/kernel/setup_mm.c
index ad0195c..528484f 100644
--- a/arch/m68k/kernel/setup_mm.c
+++ b/arch/m68k/kernel/setup_mm.c
@@ -24,6 +24,7 @@
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 #include <linux/module.h>
+#include <linux/nvram.h>
 #include <linux/initrd.h>
 
 #include <asm/bootinfo.h>
@@ -37,13 +38,14 @@
 #ifdef CONFIG_AMIGA
 #include <asm/amigahw.h>
 #endif
-#ifdef CONFIG_ATARI
 #include <asm/atarihw.h>
+#ifdef CONFIG_ATARI
 #include <asm/atari_stram.h>
 #endif
 #ifdef CONFIG_SUN3X
 #include <asm/dvma.h>
 #endif
+#include <asm/macintosh.h>
 #include <asm/natfeat.h>
 
 #if !FPSTATESIZE || !NR_IRQS
@@ -547,3 +549,81 @@ static int __init adb_probe_sync_enable (char *str) {
 
 __setup("adb_sync", adb_probe_sync_enable);
 #endif /* CONFIG_ADB */
+
+#if IS_ENABLED(CONFIG_NVRAM)
+#ifdef CONFIG_MAC
+static unsigned char m68k_nvram_read_byte(int addr)
+{
+	if (MACH_IS_MAC)
+		return mac_pram_read_byte(addr);
+	return 0xff;
+}
+
+static void m68k_nvram_write_byte(unsigned char val, int addr)
+{
+	if (MACH_IS_MAC)
+		mac_pram_write_byte(val, addr);
+}
+#endif /* CONFIG_MAC */
+
+#ifdef CONFIG_ATARI
+static ssize_t m68k_nvram_read(char *buf, size_t count, loff_t *ppos)
+{
+	if (MACH_IS_ATARI)
+		return atari_nvram_read(buf, count, ppos);
+	else if (MACH_IS_MAC)
+		return nvram_read_bytes(buf, count, ppos);
+	return -EINVAL;
+}
+
+static ssize_t m68k_nvram_write(char *buf, size_t count, loff_t *ppos)
+{
+	if (MACH_IS_ATARI)
+		return atari_nvram_write(buf, count, ppos);
+	else if (MACH_IS_MAC)
+		return nvram_write_bytes(buf, count, ppos);
+	return -EINVAL;
+}
+
+static long m68k_nvram_set_checksum(void)
+{
+	if (MACH_IS_ATARI)
+		return atari_nvram_set_checksum();
+	return -EINVAL;
+}
+
+static long m68k_nvram_initialize(void)
+{
+	if (MACH_IS_ATARI)
+		return atari_nvram_initialize();
+	return -EINVAL;
+}
+#endif /* CONFIG_ATARI */
+
+static ssize_t m68k_nvram_get_size(void)
+{
+	if (MACH_IS_ATARI)
+		return atari_nvram_get_size();
+	else if (MACH_IS_MAC)
+		return mac_pram_get_size();
+	return -ENODEV;
+}
+
+/* Atari device drivers call .read (to get checksum validation) whereas
+ * Mac and PowerMac device drivers just use .read_byte.
+ */
+const struct nvram_ops arch_nvram_ops = {
+#ifdef CONFIG_MAC
+	.read_byte      = m68k_nvram_read_byte,
+	.write_byte     = m68k_nvram_write_byte,
+#endif
+#ifdef CONFIG_ATARI
+	.read           = m68k_nvram_read,
+	.write          = m68k_nvram_write,
+	.set_checksum   = m68k_nvram_set_checksum,
+	.initialize     = m68k_nvram_initialize,
+#endif
+	.get_size       = m68k_nvram_get_size,
+};
+EXPORT_SYMBOL(arch_nvram_ops);
+#endif /* CONFIG_NVRAM */
diff --git a/arch/m68k/mac/misc.c b/arch/m68k/mac/misc.c
index d016ca2..5dc8d1e 100644
--- a/arch/m68k/mac/misc.c
+++ b/arch/m68k/mac/misc.c
@@ -36,6 +36,7 @@
 
 static void (*rom_reset)(void);
 
+#if IS_ENABLED(CONFIG_NVRAM)
 #ifdef CONFIG_ADB_CUDA
 static unsigned char cuda_pram_read_byte(int offset)
 {
@@ -84,6 +85,7 @@ static void pmu_pram_write_byte(unsigned char data, int offset)
 	pmu_wait_complete(&req);
 }
 #endif /* CONFIG_ADB_PMU */
+#endif /* CONFIG_NVRAM */
 
 /*
  * VIA PRAM/RTC access routines
@@ -205,6 +207,7 @@ static void via_rtc_command(int command, __u8 *data)
 	local_irq_restore(flags);
 }
 
+#if IS_ENABLED(CONFIG_NVRAM)
 static unsigned char via_pram_read_byte(int offset)
 {
 	unsigned char temp;
@@ -227,6 +230,7 @@ static void via_pram_write_byte(unsigned char data, int offset)
 	temp = 0x55 | RTC_FLG_WRITE_PROTECT;
 	via_rtc_command(RTC_CMD_WRITE(RTC_REG_WRITE_PROTECT), &temp);
 }
+#endif /* CONFIG_NVRAM */
 
 /*
  * Return the current time in seconds since January 1, 1904.
@@ -372,6 +376,7 @@ static void cuda_shutdown(void)
  *-------------------------------------------------------------------
  */
 
+#if IS_ENABLED(CONFIG_NVRAM)
 unsigned char mac_pram_read_byte(int addr)
 {
 	switch (macintosh_config->adb_type) {
@@ -417,6 +422,12 @@ void mac_pram_write_byte(unsigned char val, int addr)
 	}
 }
 
+ssize_t mac_pram_get_size(void)
+{
+	return 256;
+}
+#endif /* CONFIG_NVRAM */
+
 void mac_poweroff(void)
 {
 	if (oss_present) {

The commit for this change in Linux stable tree is d3b41b6 (patch).

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