diff options
Diffstat (limited to 'drivers/clk/mvebu/clk-cpu.c')
| -rw-r--r-- | drivers/clk/mvebu/clk-cpu.c | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/drivers/clk/mvebu/clk-cpu.c b/drivers/clk/mvebu/clk-cpu.c new file mode 100644 index 000000000..072aa3837 --- /dev/null +++ b/drivers/clk/mvebu/clk-cpu.c @@ -0,0 +1,255 @@ +/* + * 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/slab.h> +#include <linux/clk.h> +#include <linux/clk-provider.h> +#include <linux/of_address.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/delay.h> +#include <linux/mvebu-pmsu.h> +#include <asm/smp_plat.h> + +#define SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET 0x0 +#define SYS_CTRL_CLK_DIVIDER_CTRL_RESET_ALL 0xff +#define SYS_CTRL_CLK_DIVIDER_CTRL_RESET_SHIFT 8 +#define SYS_CTRL_CLK_DIVIDER_CTRL2_OFFSET 0x8 +#define SYS_CTRL_CLK_DIVIDER_CTRL2_NBCLK_RATIO_SHIFT 16 +#define SYS_CTRL_CLK_DIVIDER_VALUE_OFFSET 0xC +#define SYS_CTRL_CLK_DIVIDER_MASK 0x3F + +#define PMU_DFS_RATIO_SHIFT 16 +#define PMU_DFS_RATIO_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; + void __iomem *pmu_dfs; +}; + +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_off_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 int clk_cpu_on_set_rate(struct clk_hw *hwclk, unsigned long rate, + unsigned long parent_rate) +{ + u32 reg; + unsigned long fabric_div, target_div, cur_rate; + struct cpu_clk *cpuclk = to_cpu_clk(hwclk); + + /* + * PMU DFS registers are not mapped, Device Tree does not + * describes them. We cannot change the frequency dynamically. + */ + if (!cpuclk->pmu_dfs) + return -ENODEV; + + cur_rate = clk_hw_get_rate(hwclk); + + reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL2_OFFSET); + fabric_div = (reg >> SYS_CTRL_CLK_DIVIDER_CTRL2_NBCLK_RATIO_SHIFT) & + SYS_CTRL_CLK_DIVIDER_MASK; + + /* Frequency is going up */ + if (rate == 2 * cur_rate) + target_div = fabric_div / 2; + /* Frequency is going down */ + else + target_div = fabric_div; + + if (target_div == 0) + target_div = 1; + + reg = readl(cpuclk->pmu_dfs); + reg &= ~(PMU_DFS_RATIO_MASK << PMU_DFS_RATIO_SHIFT); + reg |= (target_div << PMU_DFS_RATIO_SHIFT); + writel(reg, cpuclk->pmu_dfs); + + reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET); + reg |= (SYS_CTRL_CLK_DIVIDER_CTRL_RESET_ALL << + SYS_CTRL_CLK_DIVIDER_CTRL_RESET_SHIFT); + writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET); + + return mvebu_pmsu_dfs_request(cpuclk->cpu); +} + +static int clk_cpu_set_rate(struct clk_hw *hwclk, unsigned long rate, + unsigned long parent_rate) +{ + if (__clk_is_enabled(hwclk->clk)) + return clk_cpu_on_set_rate(hwclk, rate, parent_rate); + else + return clk_cpu_off_set_rate(hwclk, rate, parent_rate); +} + +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, +}; + +static void __init of_cpu_clk_setup(struct device_node *node) +{ + struct cpu_clk *cpuclk; + void __iomem *clock_complex_base = of_iomap(node, 0); + void __iomem *pmu_dfs_base = of_iomap(node, 1); + int ncpus = 0; + struct device_node *dn; + + if (clock_complex_base == NULL) { + pr_err("%s: clock-complex base register not set\n", + __func__); + return; + } + + if (pmu_dfs_base == NULL) + pr_warn("%s: pmu-dfs base register not set, dynamic frequency scaling not available\n", + __func__); + + for_each_node_by_type(dn, "cpu") + ncpus++; + + cpuclk = kcalloc(ncpus, sizeof(*cpuclk), GFP_KERNEL); + if (WARN_ON(!cpuclk)) + goto cpuclk_out; + + clks = kcalloc(ncpus, sizeof(*clks), GFP_KERNEL); + if (WARN_ON(!clks)) + goto clks_out; + + for_each_node_by_type(dn, "cpu") { + struct clk_init_data init; + struct clk *clk; + char *clk_name = kzalloc(5, GFP_KERNEL); + int cpu, err; + + if (WARN_ON(!clk_name)) + goto bail_out; + + err = of_property_read_u32(dn, "reg", &cpu); + if (WARN_ON(err)) + goto bail_out; + + sprintf(clk_name, "cpu%d", cpu); + + cpuclk[cpu].parent_name = of_clk_get_parent_name(node, 0); + cpuclk[cpu].clk_name = clk_name; + cpuclk[cpu].cpu = cpu; + cpuclk[cpu].reg_base = clock_complex_base; + if (pmu_dfs_base) + cpuclk[cpu].pmu_dfs = pmu_dfs_base + 4 * cpu; + 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); + while(ncpus--) + kfree(cpuclk[ncpus].clk_name); +clks_out: + kfree(cpuclk); +cpuclk_out: + iounmap(clock_complex_base); +} + +CLK_OF_DECLARE(armada_xp_cpu_clock, "marvell,armada-xp-cpu-clock", + of_cpu_clk_setup); + +static void __init of_mv98dx3236_cpu_clk_setup(struct device_node *node) +{ + of_clk_add_provider(node, of_clk_src_simple_get, NULL); +} + +CLK_OF_DECLARE(mv98dx3236_cpu_clock, "marvell,mv98dx3236-cpu-clock", + of_mv98dx3236_cpu_clk_setup); |