diff options
Diffstat (limited to 'drivers/clk/mvebu/clk-cpu.c')
| -rw-r--r-- | drivers/clk/mvebu/clk-cpu.c | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/drivers/clk/mvebu/clk-cpu.c b/drivers/clk/mvebu/clk-cpu.c new file mode 100644 index 0000000..ff004578 --- /dev/null +++ b/drivers/clk/mvebu/clk-cpu.c @@ -0,0 +1,186 @@ +/* + * Marvell MVEBU CPU clock handling. + * + * Copyright (C) 2012 Marvell + * + * Gregory CLEMENT <gregory.clement@free-electrons.com> + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ +#include <linux/kernel.h> +#include <linux/clkdev.h> +#include <linux/clk-provider.h> +#include <linux/of_address.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/delay.h> +#include "clk-cpu.h" + +#define SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET 0x0 +#define SYS_CTRL_CLK_DIVIDER_VALUE_OFFSET 0xC +#define SYS_CTRL_CLK_DIVIDER_MASK 0x3F + +#define MAX_CPU 4 +struct cpu_clk { + struct clk_hw hw; + int cpu; + const char *clk_name; + const char *parent_name; + void __iomem *reg_base; +}; + +static struct clk **clks; + +static struct clk_onecell_data clk_data; + +#define to_cpu_clk(p) container_of(p, struct cpu_clk, hw) + +static unsigned long clk_cpu_recalc_rate(struct clk_hw *hwclk, + unsigned long parent_rate) +{ + struct cpu_clk *cpuclk = to_cpu_clk(hwclk); + u32 reg, div; + + reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_VALUE_OFFSET); + div = (reg >> (cpuclk->cpu * 8)) & SYS_CTRL_CLK_DIVIDER_MASK; + return parent_rate / div; +} + +static long clk_cpu_round_rate(struct clk_hw *hwclk, unsigned long rate, + unsigned long *parent_rate) +{ + /* Valid ratio are 1:1, 1:2 and 1:3 */ + u32 div; + + div = *parent_rate / rate; + if (div == 0) + div = 1; + else if (div > 3) + div = 3; + + return *parent_rate / div; +} + +static int clk_cpu_set_rate(struct clk_hw *hwclk, unsigned long rate, + unsigned long parent_rate) +{ + struct cpu_clk *cpuclk = to_cpu_clk(hwclk); + u32 reg, div; + u32 reload_mask; + + div = parent_rate / rate; + reg = (readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_VALUE_OFFSET) + & (~(SYS_CTRL_CLK_DIVIDER_MASK << (cpuclk->cpu * 8)))) + | (div << (cpuclk->cpu * 8)); + writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_VALUE_OFFSET); + /* Set clock divider reload smooth bit mask */ + reload_mask = 1 << (20 + cpuclk->cpu); + + reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET) + | reload_mask; + writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET); + + /* Now trigger the clock update */ + reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET) + | 1 << 24; + writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET); + + /* Wait for clocks to settle down then clear reload request */ + udelay(1000); + reg &= ~(reload_mask | 1 << 24); + writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET); + udelay(1000); + + return 0; +} + +static const struct clk_ops cpu_ops = { + .recalc_rate = clk_cpu_recalc_rate, + .round_rate = clk_cpu_round_rate, + .set_rate = clk_cpu_set_rate, +}; + +void __init of_cpu_clk_setup(struct device_node *node) +{ + struct cpu_clk *cpuclk; + void __iomem *clock_complex_base = of_iomap(node, 0); + int ncpus = 0; + struct device_node *dn; + + if (clock_complex_base == NULL) { + pr_err("%s: clock-complex base register not set\n", + __func__); + return; + } + + for_each_node_by_type(dn, "cpu") + ncpus++; + + cpuclk = kzalloc(ncpus * sizeof(*cpuclk), GFP_KERNEL); + if (WARN_ON(!cpuclk)) + return; + + clks = kzalloc(ncpus * sizeof(*clks), GFP_KERNEL); + if (WARN_ON(!clks)) + return; + + for_each_node_by_type(dn, "cpu") { + struct clk_init_data init; + struct clk *clk; + struct clk *parent_clk; + char *clk_name = kzalloc(5, GFP_KERNEL); + int cpu, err; + + if (WARN_ON(!clk_name)) + return; + + err = of_property_read_u32(dn, "reg", &cpu); + if (WARN_ON(err)) + return; + + sprintf(clk_name, "cpu%d", cpu); + parent_clk = of_clk_get(node, 0); + + cpuclk[cpu].parent_name = __clk_get_name(parent_clk); + cpuclk[cpu].clk_name = clk_name; + cpuclk[cpu].cpu = cpu; + cpuclk[cpu].reg_base = clock_complex_base; + cpuclk[cpu].hw.init = &init; + + init.name = cpuclk[cpu].clk_name; + init.ops = &cpu_ops; + init.flags = 0; + init.parent_names = &cpuclk[cpu].parent_name; + init.num_parents = 1; + + clk = clk_register(NULL, &cpuclk[cpu].hw); + if (WARN_ON(IS_ERR(clk))) + goto bail_out; + clks[cpu] = clk; + } + clk_data.clk_num = MAX_CPU; + clk_data.clks = clks; + of_clk_add_provider(node, of_clk_src_onecell_get, &clk_data); + + return; +bail_out: + kfree(clks); + kfree(cpuclk); +} + +static const __initconst struct of_device_id clk_cpu_match[] = { + { + .compatible = "marvell,armada-xp-cpu-clock", + .data = of_cpu_clk_setup, + }, + { + /* sentinel */ + }, +}; + +void __init mvebu_cpu_clk_init(void) +{ + of_clk_init(clk_cpu_match); +} |