Support AT91CAP9 revC CPUs

The AT91CAP9 revC CPU has a few differences over the previous,
revB CPU which was distributed in small quantities only (revA was
an internal Atmel product only).

The revC silicon needs a special initialisation sequence to
switch from the internal (imprecise) RC oscillator to the
external 32k clock.

Signed-off-by: Stelian Pop <stelian@popies.net>
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

board/atmel/at91cap9adk/at91cap9adk.c

@@ -72,6 +72,33 @@ static void at91cap9_serial_hw_init(void)
 #endif
 }
 
+static void at91cap9_slowclock_hw_init(void)
+{
+	/*
+	 * On AT91CAP9 revC CPUs, the slow clock can be based on an
+	 * internal impreciseRC oscillator or an external 32kHz oscillator.
+	 * Switch to the latter.
+	 */
+#define ARCH_ID_AT91CAP9_REVB	0x399
+#define ARCH_ID_AT91CAP9_REVC	0x601
+	if (at91_sys_read(AT91_PMC_VER) == ARCH_ID_AT91CAP9_REVC) {
+		unsigned i, tmp = at91_sys_read(AT91_SCKCR);
+		if ((tmp & AT91CAP9_SCKCR_OSCSEL) == AT91CAP9_SCKCR_OSCSEL_RC) {
+			extern void timer_init(void);
+			timer_init();
+			tmp |= AT91CAP9_SCKCR_OSC32EN;
+			at91_sys_write(AT91_SCKCR, tmp);
+			for (i = 0; i < 1200; i++)
+				udelay(1000);
+			tmp |= AT91CAP9_SCKCR_OSCSEL_32;
+			at91_sys_write(AT91_SCKCR, tmp);
+			udelay(200);
+			tmp &= ~AT91CAP9_SCKCR_RCEN;
+			at91_sys_write(AT91_SCKCR, tmp);
+		}
+	}
+}
+
 static void at91cap9_nor_hw_init(void)
 {
 	unsigned long csa;
@@ -305,6 +332,7 @@ int board_init(void)
 	gd->bd->bi_boot_params = PHYS_SDRAM + 0x100;
 
 	at91cap9_serial_hw_init();
+	at91cap9_slowclock_hw_init();
 	at91cap9_nor_hw_init();
 #ifdef CONFIG_CMD_NAND
 	at91cap9_nand_hw_init();

include/asm-arm/arch-at91sam9/at91_pmc.h

@@ -96,4 +96,9 @@
 #define		AT91_PMC_PCK3RDY	(1 << 11)		/* Programmable Clock 3 */
 #define	AT91_PMC_IMR		(AT91_PMC + 0x6c)	/* Interrupt Mask Register */
 
+#define AT91_PMC_PROT		(AT91_PMC + 0xe4)	/* Protect Register [AT91CAP9 revC only] */
+#define		AT91_PMC_PROTKEY	0x504d4301		/* Activation Code */
+
+#define AT91_PMC_VER	(AT91_PMC + 0xfc)	/* PMC Module Version [AT91CAP9 only] */
+
 #endif

include/asm-arm/arch-at91sam9/at91cap9.h

@@ -101,12 +101,24 @@
 #define AT91_RTT	(0xfffffd20 - AT91_BASE_SYS)
 #define AT91_PIT	(0xfffffd30 - AT91_BASE_SYS)
 #define AT91_WDT	(0xfffffd40 - AT91_BASE_SYS)
-#define AT91_GPBR	(0xfffffd50 - AT91_BASE_SYS)
+#define AT91_SCKCR	(0xfffffd50 - AT91_BASE_SYS)
+#define AT91_GPBR_REVB	(0xfffffd50 - AT91_BASE_SYS)
+#define AT91_GPBR_REVC	(0xfffffd60 - AT91_BASE_SYS)
 
 #define AT91_USART0	AT91CAP9_BASE_US0
 #define AT91_USART1	AT91CAP9_BASE_US1
 #define AT91_USART2	AT91CAP9_BASE_US2
 
+/*
+ * SCKCR flags
+ */
+#define AT91CAP9_SCKCR_RCEN	(1 << 0)	/* RC Oscillator Enable */
+#define AT91CAP9_SCKCR_OSC32EN	(1 << 1)	/* 32kHz Oscillator Enable */
+#define AT91CAP9_SCKCR_OSC32BYP	(1 << 2)	/* 32kHz Oscillator Bypass */
+#define AT91CAP9_SCKCR_OSCSEL	(1 << 3)	/* Slow Clock Selector */
+#define		AT91CAP9_SCKCR_OSCSEL_RC	(0 << 3)
+#define		AT91CAP9_SCKCR_OSCSEL_32	(1 << 3)
+
 /*
  * Internal Memory.
  */