1 files changed, 44 insertions, 21 deletions

diff --git a/arch/mips/alchemy/common/clocks.c b/arch/mips/alchemy/common/clocks.c
index 043429d17c5f..d8991854530e 100644
--- a/arch/mips/alchemy/common/clocks.c
+++ b/arch/mips/alchemy/common/clocks.c
@@ -27,12 +27,21 @@
  */
 
 #include <linux/module.h>
+#include <linux/spinlock.h>
+#include <asm/time.h>
 #include <asm/mach-au1x00/au1000.h>
 
+/*
+ * I haven't found anyone that doesn't use a 12 MHz source clock,
+ * but just in case.....
+ */
+#define AU1000_SRC_CLK	12000000
+
 static unsigned int au1x00_clock; /*  Hz */
-static unsigned int lcd_clock;    /* KHz */
 static unsigned long uart_baud_base;
 
+static DEFINE_SPINLOCK(time_lock);
+
 /*
  * Set the au1000_clock
  */
@@ -63,31 +72,45 @@ void set_au1x00_uart_baud_base(unsigned long new_baud_base)
 }
 
 /*
- * Calculate the Au1x00's LCD clock based on the current
- * cpu clock and the system bus clock, and try to keep it
- * below 40 MHz (the Pb1000 board can lock-up if the LCD
- * clock is over 40 MHz).
+ * We read the real processor speed from the PLL.  This is important
+ * because it is more accurate than computing it from the 32 KHz
+ * counter, if it exists.  If we don't have an accurate processor
+ * speed, all of the peripherals that derive their clocks based on
+ * this advertised speed will introduce error and sometimes not work
+ * properly.  This function is futher convoluted to still allow configurations
+ * to do that in case they have really, really old silicon with a
+ * write-only PLL register.			-- Dan
  */
-void set_au1x00_lcd_clock(void)
+unsigned long au1xxx_calc_clock(void)
 {
-	unsigned int static_cfg0;
-	unsigned int sys_busclk = (get_au1x00_speed() / 1000) /
-				  ((int)(au_readl(SYS_POWERCTRL) & 0x03) + 2);
+	unsigned long cpu_speed;
+	unsigned long flags;
 
-	static_cfg0 = au_readl(MEM_STCFG0);
+	spin_lock_irqsave(&time_lock, flags);
 
-	if (static_cfg0 & (1 << 11))
-		lcd_clock = sys_busclk / 5; /* note: BCLK switching fails with D5 */
+	/*
+	 * On early Au1000, sys_cpupll was write-only. Since these
+	 * silicon versions of Au1000 are not sold by AMD, we don't bend
+	 * over backwards trying to determine the frequency.
+	 */
+	if (au1xxx_cpu_has_pll_wo())
+#ifdef CONFIG_SOC_AU1000_FREQUENCY
+		cpu_speed = CONFIG_SOC_AU1000_FREQUENCY;
+#else
+		cpu_speed = 396000000;
+#endif
 	else
-		lcd_clock = sys_busclk / 4;
+		cpu_speed = (au_readl(SYS_CPUPLL) & 0x0000003f) * AU1000_SRC_CLK;
 
-	if (lcd_clock > 50000) /* Epson MAX */
-		printk(KERN_WARNING "warning: LCD clock too high (%u KHz)\n",
-				    lcd_clock);
-}
+	/* On Alchemy CPU:counter ratio is 1:1 */
+	mips_hpt_frequency = cpu_speed;
+	/* Equation: Baudrate = CPU / (SD * 2 * CLKDIV * 16) */
+	set_au1x00_uart_baud_base(cpu_speed / (2 * ((int)(au_readl(SYS_POWERCTRL)
+							  & 0x03) + 2) * 16));
 
-unsigned int get_au1x00_lcd_clock(void)
-{
-	return lcd_clock;
+	spin_unlock_irqrestore(&time_lock, flags);
+
+	set_au1x00_speed(cpu_speed);
+
+	return cpu_speed;
 }
-EXPORT_SYMBOL(get_au1x00_lcd_clock);