ARM: tegra: Implement clk_m

On currently supported SoCs, clk_m always runs at the same frequency as
the oscillator input. However newer SoC generations such as Tegra210 no
longer have that restriction. Prepare for that by separating clk_m from
the oscillator clock and allow SoC code to override the clk_m rate.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>

arch/arm/include/asm/arch-tegra/clock.h

@@ -44,6 +44,9 @@ enum {
 /* return the current oscillator clock frequency */
 enum clock_osc_freq clock_get_osc_freq(void);
 
+/* return the clk_m frequency */
+unsigned int clk_m_get_rate(unsigned int parent_rate);
+
 /**
  * Start PLL using the provided configuration parameters.
  *
@@ -338,8 +341,8 @@ void arch_timer_init(void);
 
 void tegra30_set_up_pllp(void);
 
-/* Number of PLL-based clocks (i.e. not OSC or 32KHz) */
+/* Number of PLL-based clocks (i.e. not OSC, MCLK or 32KHz) */
-#define CLOCK_ID_PLL_COUNT	(CLOCK_ID_COUNT - 2)
+#define CLOCK_ID_PLL_COUNT	(CLOCK_ID_COUNT - 3)
 
 struct clk_pll_info {
 	u32	m_shift:5;	/* DIVM_SHIFT */

arch/arm/include/asm/arch-tegra114/clock-tables.h

@@ -38,6 +38,7 @@ enum clock_id {
 	/* These are the base clocks (inputs to the Tegra SOC) */
 	CLOCK_ID_32KHZ,
 	CLOCK_ID_OSC,
+	CLOCK_ID_CLK_M,
 
 	CLOCK_ID_COUNT,	/* number of PLLs */
 	CLOCK_ID_DISPLAY2,	/* placeholder */

arch/arm/include/asm/arch-tegra124/clock-tables.h

@@ -30,6 +30,7 @@ enum clock_id {
 	/* These are the base clocks (inputs to the Tegra SoC) */
 	CLOCK_ID_32KHZ,
 	CLOCK_ID_OSC,
+	CLOCK_ID_CLK_M,
 
 	CLOCK_ID_COUNT,	/* number of PLLs */
 

arch/arm/include/asm/arch-tegra20/clock-tables.h

@@ -29,6 +29,7 @@ enum clock_id {
 	/* These are the base clocks (inputs to the Tegra SOC) */
 	CLOCK_ID_32KHZ,
 	CLOCK_ID_OSC,
+	CLOCK_ID_CLK_M,
 
 	CLOCK_ID_COUNT,	/* number of clocks */
 	CLOCK_ID_NONE = -1,

arch/arm/include/asm/arch-tegra210/clock-tables.h

@@ -30,6 +30,7 @@ enum clock_id {
 	/* These are the base clocks (inputs to the Tegra SoC) */
 	CLOCK_ID_32KHZ,
 	CLOCK_ID_OSC,
+	CLOCK_ID_CLK_M,
 
 	CLOCK_ID_COUNT,	/* number of PLLs */
 

arch/arm/include/asm/arch-tegra30/clock-tables.h

@@ -38,6 +38,7 @@ enum clock_id {
 	/* These are the base clocks (inputs to the Tegra SOC) */
 	CLOCK_ID_32KHZ,
 	CLOCK_ID_OSC,
+	CLOCK_ID_CLK_M,
 
 	CLOCK_ID_COUNT,	/* number of PLLs */
 	CLOCK_ID_DISPLAY2,	/* Tegra3, placeholder */

arch/arm/mach-tegra/clock.c

@@ -461,6 +461,11 @@ void reset_cmplx_set_enable(int cpu, int which, int reset)
 		writel(mask, &clkrst->crc_cpu_cmplx_clr);
 }
 
+unsigned int __weak clk_m_get_rate(unsigned int parent_rate)
+{
+	return parent_rate;
+}
+
 unsigned clock_get_rate(enum clock_id clkid)
 {
 	struct clk_pll *pll;
@@ -472,6 +477,9 @@ unsigned clock_get_rate(enum clock_id clkid)
 	if (clkid == CLOCK_ID_OSC)
 		return parent_rate;
 
+	if (clkid == CLOCK_ID_CLK_M)
+		return clk_m_get_rate(parent_rate);
+
 	pll = get_pll(clkid);
 	if (!pll)
 		return 0;
@@ -622,8 +630,10 @@ void clock_init(void)
 	pll_rate[CLOCK_ID_XCPU] = clock_get_rate(CLOCK_ID_XCPU);
 	pll_rate[CLOCK_ID_SFROM32KHZ] = 32768;
 	pll_rate[CLOCK_ID_OSC] = clock_get_rate(CLOCK_ID_OSC);
+	pll_rate[CLOCK_ID_CLK_M] = clock_get_rate(CLOCK_ID_CLK_M);
 
 	debug("Osc = %d\n", pll_rate[CLOCK_ID_OSC]);
+	debug("CLKM = %d\n", pll_rate[CLOCK_ID_CLK_M]);
 	debug("PLLC = %d\n", pll_rate[CLOCK_ID_CGENERAL]);
 	debug("PLLM = %d\n", pll_rate[CLOCK_ID_MEMORY]);
 	debug("PLLP = %d\n", pll_rate[CLOCK_ID_PERIPH]);

arch/arm/mach-tegra/tegra210/clock.c

@@ -998,6 +998,17 @@ void clock_early_init(void)
 	udelay(2);
 }
 
+unsigned int clk_m_get_rate(unsigned parent_rate)
+{
+	struct clk_rst_ctlr *clkrst = (struct clk_rst_ctlr *)NV_PA_CLK_RST_BASE;
+	u32 value, div;
+
+	value = readl(&clkrst->crc_spare_reg0);
+	div = ((value >> 2) & 0x3) + 1;
+
+	return parent_rate / div;
+}
+
 void arch_timer_init(void)
 {
 	struct sysctr_ctlr *sysctr = (struct sysctr_ctlr *)NV_PA_TSC_BASE;