MIPS: ralink: mt7620: Improve clock frequency detection

The current code assumes that the peripheral clock always
runs at 40MHz which is not true in all configuration. The
peripheral clock can also use the reference clock instead
of the fixed 40MHz rate. If the reference clock runs at a
different rate, various peripheries are behaving incorrectly.

Additionally, the currectly calculated system clock is also
wrong. The actual value what the code computes is the rate
of the DRAM which can be different from the system clock.

Add new helper functions to get the rate of the different
clocks and use the correct values for the registered clock
devices.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5755/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 32 insertions, 8 deletions

diff --git a/arch/mips/include/asm/mach-ralink/mt7620.h b/arch/mips/include/asm/mach-ralink/mt7620.h
index 9809972ea88..6f9b24f5115 100644
--- a/arch/mips/include/asm/mach-ralink/mt7620.h
+++ b/arch/mips/include/asm/mach-ralink/mt7620.h
@@ -20,6 +20,8 @@
 #define SYSC_REG_CHIP_REV		0x0c
 #define SYSC_REG_SYSTEM_CONFIG0		0x10
 #define SYSC_REG_SYSTEM_CONFIG1		0x14
+#define SYSC_REG_CLKCFG0		0x2c
+#define SYSC_REG_CPU_SYS_CLKCFG		0x3c
 #define SYSC_REG_CPLL_CONFIG0		0x54
 #define SYSC_REG_CPLL_CONFIG1		0x58
 
@@ -29,20 +31,42 @@
 #define MT7620A_CHIP_NAME0		0x3637544d
 #define MT7620A_CHIP_NAME1		0x20203032
 
+#define SYSCFG0_XTAL_FREQ_SEL		BIT(6)
+
 #define CHIP_REV_PKG_MASK		0x1
 #define CHIP_REV_PKG_SHIFT		16
 #define CHIP_REV_VER_MASK		0xf
 #define CHIP_REV_VER_SHIFT		8
 #define CHIP_REV_ECO_MASK		0xf
 
-#define CPLL_SW_CONFIG_SHIFT		31
-#define CPLL_SW_CONFIG_MASK		0x1
-#define CPLL_CPU_CLK_SHIFT		24
-#define CPLL_CPU_CLK_MASK		0x1
-#define CPLL_MULT_RATIO_SHIFT           16
-#define CPLL_MULT_RATIO                 0x7
-#define CPLL_DIV_RATIO_SHIFT            10
-#define CPLL_DIV_RATIO                  0x3
+#define CLKCFG0_PERI_CLK_SEL		BIT(4)
+
+#define CPU_SYS_CLKCFG_OCP_RATIO_SHIFT	16
+#define CPU_SYS_CLKCFG_OCP_RATIO_MASK	0xf
+#define CPU_SYS_CLKCFG_OCP_RATIO_1	0	/* 1:1   (Reserved) */
+#define CPU_SYS_CLKCFG_OCP_RATIO_1_5	1	/* 1:1.5 (Reserved) */
+#define CPU_SYS_CLKCFG_OCP_RATIO_2	2	/* 1:2   */
+#define CPU_SYS_CLKCFG_OCP_RATIO_2_5	3       /* 1:2.5 (Reserved) */
+#define CPU_SYS_CLKCFG_OCP_RATIO_3	4	/* 1:3   */
+#define CPU_SYS_CLKCFG_OCP_RATIO_3_5	5	/* 1:3.5 (Reserved) */
+#define CPU_SYS_CLKCFG_OCP_RATIO_4	6	/* 1:4   */
+#define CPU_SYS_CLKCFG_OCP_RATIO_5	7	/* 1:5   */
+#define CPU_SYS_CLKCFG_OCP_RATIO_10	8	/* 1:10  */
+#define CPU_SYS_CLKCFG_CPU_FDIV_SHIFT	8
+#define CPU_SYS_CLKCFG_CPU_FDIV_MASK	0x1f
+#define CPU_SYS_CLKCFG_CPU_FFRAC_SHIFT	0
+#define CPU_SYS_CLKCFG_CPU_FFRAC_MASK	0x1f
+
+#define CPLL_CFG0_SW_CFG		BIT(31)
+#define CPLL_CFG0_PLL_MULT_RATIO_SHIFT	16
+#define CPLL_CFG0_PLL_MULT_RATIO_MASK   0x7
+#define CPLL_CFG0_LC_CURFCK		BIT(15)
+#define CPLL_CFG0_BYPASS_REF_CLK	BIT(14)
+#define CPLL_CFG0_PLL_DIV_RATIO_SHIFT	10
+#define CPLL_CFG0_PLL_DIV_RATIO_MASK	0x3
+
+#define CPLL_CFG1_CPU_AUX1		BIT(25)
+#define CPLL_CFG1_CPU_AUX0		BIT(24)
 
 #define SYSCFG0_DRAM_TYPE_MASK		0x3
 #define SYSCFG0_DRAM_TYPE_SHIFT		4