For a long time the mt7621 uses a fixed cpu clock which causes a problem
if the cpu frequency is not 880MHz.
This patch adds cpu/ahb/apb clock calculation code and binds clocks to
mt7621-pll node.
Adapted from OpenWrt:
c7ca224299 ramips: fix cpu clock of mt7621 and add dt clk devices
Signed-off-by: Weijie Gao <hackpascal@xxxxxxxxx>
Signed-off-by: Chuanhong Guo <gch981213@xxxxxxxxx>
Signed-off-by: Sergio Paracuellos <sergio.paracuellos@xxxxxxxxx>
---
arch/mips/include/asm/mach-ralink/mt7621.h | 20 +++++
arch/mips/ralink/mt7621.c | 87 ++++++++++++++++++++++
2 files changed, 107 insertions(+)
diff --git a/arch/mips/include/asm/mach-ralink/mt7621.h b/arch/mips/include/asm/mach-ralink/mt7621.h
index e1af1ba50bd8..a9f3febddf1c 100644
--- a/arch/mips/include/asm/mach-ralink/mt7621.h
+++ b/arch/mips/include/asm/mach-ralink/mt7621.h
@@ -17,6 +17,10 @@
#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_CUR_CLK_STS 0x44
+
+#define MEMC_REG_CPU_PLL 0x648
#define CHIP_REV_PKG_MASK 0x1
#define CHIP_REV_PKG_SHIFT 16
@@ -24,6 +28,22 @@
#define CHIP_REV_VER_SHIFT 8
#define CHIP_REV_ECO_MASK 0xf
+#define XTAL_MODE_SEL_MASK 0x7
+#define XTAL_MODE_SEL_SHIFT 6
+
+#define CPU_CLK_SEL_MASK 0x3
+#define CPU_CLK_SEL_SHIFT 30
+
+#define CUR_CPU_FDIV_MASK 0x1f
+#define CUR_CPU_FDIV_SHIFT 8
+#define CUR_CPU_FFRAC_MASK 0x1f
+#define CUR_CPU_FFRAC_SHIFT 0
+
+#define CPU_PLL_PREDIV_MASK 0x3
+#define CPU_PLL_PREDIV_SHIFT 12
+#define CPU_PLL_FBDIV_MASK 0x7f
+#define CPU_PLL_FBDIV_SHIFT 4
+
#define MT7621_DRAM_BASE 0x0
#define MT7621_DDR2_SIZE_MIN 32
#define MT7621_DDR2_SIZE_MAX 256
diff --git a/arch/mips/ralink/mt7621.c b/arch/mips/ralink/mt7621.c
index ca0ac607b0f3..4fce37e5ea7a 100644
--- a/arch/mips/ralink/mt7621.c
+++ b/arch/mips/ralink/mt7621.c
@@ -9,12 +9,17 @@
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/sys_soc.h>
+#include <linux/clk.h>
+#include <linux/clkdev.h>
+#include <linux/clk-provider.h>
+#include <dt-bindings/clock/mt7621-clk.h>
#include <asm/mipsregs.h>
#include <asm/smp-ops.h>
#include <asm/mips-cps.h>
#include <asm/mach-ralink/ralink_regs.h>
#include <asm/mach-ralink/mt7621.h>
+#include <asm/time.h>
#include <pinmux.h>
@@ -105,11 +110,93 @@ static struct rt2880_pmx_group mt7621_pinmux_data[] = {
{ 0 }
};
+static struct clk *clks[MT7621_CLK_MAX];
+static struct clk_onecell_data clk_data = {
+ .clks = clks,
+ .clk_num = ARRAY_SIZE(clks),
+};
+
phys_addr_t mips_cpc_default_phys_base(void)
{
panic("Cannot detect cpc address");
}
+static struct clk *__init mt7621_add_sys_clkdev(
+ const char *id, const char *parent_id, unsigned long rate)
+{
+ struct clk *clk;
+ int err;
+
+ clk = clk_register_fixed_rate(NULL, id, parent_id, 0, rate);
+ if (IS_ERR(clk))
+ panic("failed to allocate %s clock structure", id);
+
+ err = clk_register_clkdev(clk, id, NULL);
+ if (err)
+ panic("unable to register %s clock device", id);
+
+ return clk;
+}
+
+#define MHZ(x) ((x) * 1000 * 1000)
+
+void __init ralink_clk_init(void)
+{
+ u32 syscfg, xtal_sel, clkcfg, clk_sel, curclk, ffiv, ffrac;
+ u32 pll, prediv, fbdiv;
+ u32 xtal_clk, cpu_clk, ahb_clk, apb_clk;
+ static const u32 prediv_tbl[] = { 0, 1, 2, 2 };
+
+ syscfg = rt_sysc_r32(SYSC_REG_SYSTEM_CONFIG0);
+ xtal_sel = (syscfg >> XTAL_MODE_SEL_SHIFT) & XTAL_MODE_SEL_MASK;
+
+ clkcfg = rt_sysc_r32(SYSC_REG_CLKCFG0);
+ clk_sel = (clkcfg >> CPU_CLK_SEL_SHIFT) & CPU_CLK_SEL_MASK;
+
+ curclk = rt_sysc_r32(SYSC_REG_CUR_CLK_STS);
+ ffiv = (curclk >> CUR_CPU_FDIV_SHIFT) & CUR_CPU_FDIV_MASK;
+ ffrac = (curclk >> CUR_CPU_FFRAC_SHIFT) & CUR_CPU_FFRAC_MASK;
+
+ if (xtal_sel <= 2)
+ xtal_clk = MHZ(20);
+ else if (xtal_sel <= 5)
+ xtal_clk = MHZ(40);
+ else
+ xtal_clk = MHZ(25);
+
+ switch (clk_sel) {
+ case 0:
+ cpu_clk = MHZ(500);
+ break;
+ case 1:
+ pll = rt_memc_r32(MEMC_REG_CPU_PLL);
+ fbdiv = (pll >> CPU_PLL_FBDIV_SHIFT) & CPU_PLL_FBDIV_MASK;
+ prediv = (pll >> CPU_PLL_PREDIV_SHIFT) & CPU_PLL_PREDIV_MASK;
+ cpu_clk = ((fbdiv + 1) * xtal_clk) >> prediv_tbl[prediv];
+ break;
+ default:
+ cpu_clk = xtal_clk;
+ }
+
+ cpu_clk = cpu_clk / ffiv * ffrac;
+ ahb_clk = cpu_clk / 4;
+ apb_clk = MHZ(50);
+
+ clks[MT7621_CLK_CPU] = mt7621_add_sys_clkdev("cpu", NULL, cpu_clk);
+ clks[MT7621_CLK_AHB] = mt7621_add_sys_clkdev("ahb", NULL, ahb_clk);
+ clks[MT7621_CLK_APB] = mt7621_add_sys_clkdev("apb", NULL, apb_clk);
+
+ pr_info("CPU Clock: %dMHz\n", cpu_clk / 1000000);
+ mips_hpt_frequency = cpu_clk / 2;
+}
+
+static void __init mt7621_clocks_init_dt(struct device_node *np)
+{
+ of_clk_add_provider(np, of_clk_src_onecell_get, &clk_data);
+}
+
+CLK_OF_DECLARE(ar7100, "mediatek,mt7621-pll", mt7621_clocks_init_dt);
+
void __init ralink_of_remap(void)
{
rt_sysc_membase = plat_of_remap_node("mtk,mt7621-sysc");
--
2.25.1
