Signed-off-by: Finn Thain --- Tested on a PowerBook 520 and Quadra 650. --- arch/m68k/mac/misc.c | 35 +++++++++++++++++++++++++++++------ include/uapi/linux/pmu.h | 2 ++ 2 files changed, 31 insertions(+), 6 deletions(-) Index: linux/arch/m68k/mac/misc.c =================================================================== --- linux.orig/arch/m68k/mac/misc.c 2015-05-31 11:01:26.000000000 +1000 +++ linux/arch/m68k/mac/misc.c 2015-05-31 11:01:28.000000000 +1000 @@ -124,19 +124,22 @@ 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(); @@ -295,11 +298,31 @@ static void via_pram_command(int command #if IS_ENABLED(CONFIG_NVRAM) static unsigned char via_pram_read_byte(int offset) { - return 0; + unsigned char temp; + int addr = ((offset & 0xE0) << 3) | ((offset & 0x1F) << 2); + + /* Use RTC command 0x38 for XPRAM access, as per MESS source code */ + via_pram_command(addr | 0x3800 | 0x8001, &temp); + + return temp; } static void via_pram_write_byte(unsigned char data, int offset) { + unsigned char temp; + int addr = ((offset & 0xE0) << 3) | ((offset & 0x1F) << 2); + + /* Clear the write protect bit */ + temp = 0x55; + via_pram_command(0x34 | 0x01, &temp); + + /* Write the byte to XPRAM */ + temp = data; + via_pram_command(0x3800 | 0x0001 | addr, &temp); + + /* Set the write protect bit */ + temp = 0xD5; + via_pram_command(0x34 | 0x01, &temp); } #endif /* CONFIG_NVRAM */ Index: linux/include/uapi/linux/pmu.h =================================================================== --- linux.orig/include/uapi/linux/pmu.h 2015-05-31 11:00:59.000000000 +1000 +++ linux/include/uapi/linux/pmu.h 2015-05-31 11:01:28.000000000 +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 */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/