diff options
Diffstat (limited to 'kernel/drivers/clk/clk-stm32f4.c')
| -rw-r--r-- | kernel/drivers/clk/clk-stm32f4.c | 379 |
1 files changed, 379 insertions, 0 deletions
diff --git a/kernel/drivers/clk/clk-stm32f4.c b/kernel/drivers/clk/clk-stm32f4.c new file mode 100644 index 000000000..fd89e7711 --- /dev/null +++ b/kernel/drivers/clk/clk-stm32f4.c @@ -0,0 +1,379 @@ +/* + * Author: Daniel Thompson <daniel.thompson@linaro.org> + * + * Inspired by clk-asm9260.c . + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/clk-provider.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/of.h> +#include <linux/of_address.h> + +#define STM32F4_RCC_PLLCFGR 0x04 +#define STM32F4_RCC_CFGR 0x08 +#define STM32F4_RCC_AHB1ENR 0x30 +#define STM32F4_RCC_AHB2ENR 0x34 +#define STM32F4_RCC_AHB3ENR 0x38 +#define STM32F4_RCC_APB1ENR 0x40 +#define STM32F4_RCC_APB2ENR 0x44 + +struct stm32f4_gate_data { + u8 offset; + u8 bit_idx; + const char *name; + const char *parent_name; + unsigned long flags; +}; + +static const struct stm32f4_gate_data stm32f4_gates[] __initconst = { + { STM32F4_RCC_AHB1ENR, 0, "gpioa", "ahb_div" }, + { STM32F4_RCC_AHB1ENR, 1, "gpiob", "ahb_div" }, + { STM32F4_RCC_AHB1ENR, 2, "gpioc", "ahb_div" }, + { STM32F4_RCC_AHB1ENR, 3, "gpiod", "ahb_div" }, + { STM32F4_RCC_AHB1ENR, 4, "gpioe", "ahb_div" }, + { STM32F4_RCC_AHB1ENR, 5, "gpiof", "ahb_div" }, + { STM32F4_RCC_AHB1ENR, 6, "gpiog", "ahb_div" }, + { STM32F4_RCC_AHB1ENR, 7, "gpioh", "ahb_div" }, + { STM32F4_RCC_AHB1ENR, 8, "gpioi", "ahb_div" }, + { STM32F4_RCC_AHB1ENR, 9, "gpioj", "ahb_div" }, + { STM32F4_RCC_AHB1ENR, 10, "gpiok", "ahb_div" }, + { STM32F4_RCC_AHB1ENR, 12, "crc", "ahb_div" }, + { STM32F4_RCC_AHB1ENR, 18, "bkpsra", "ahb_div" }, + { STM32F4_RCC_AHB1ENR, 20, "ccmdatam", "ahb_div" }, + { STM32F4_RCC_AHB1ENR, 21, "dma1", "ahb_div" }, + { STM32F4_RCC_AHB1ENR, 22, "dma2", "ahb_div" }, + { STM32F4_RCC_AHB1ENR, 23, "dma2d", "ahb_div" }, + { STM32F4_RCC_AHB1ENR, 25, "ethmac", "ahb_div" }, + { STM32F4_RCC_AHB1ENR, 26, "ethmactx", "ahb_div" }, + { STM32F4_RCC_AHB1ENR, 27, "ethmacrx", "ahb_div" }, + { STM32F4_RCC_AHB1ENR, 28, "ethmacptp", "ahb_div" }, + { STM32F4_RCC_AHB1ENR, 29, "otghs", "ahb_div" }, + { STM32F4_RCC_AHB1ENR, 30, "otghsulpi", "ahb_div" }, + + { STM32F4_RCC_AHB2ENR, 0, "dcmi", "ahb_div" }, + { STM32F4_RCC_AHB2ENR, 4, "cryp", "ahb_div" }, + { STM32F4_RCC_AHB2ENR, 5, "hash", "ahb_div" }, + { STM32F4_RCC_AHB2ENR, 6, "rng", "pll48" }, + { STM32F4_RCC_AHB2ENR, 7, "otgfs", "pll48" }, + + { STM32F4_RCC_AHB3ENR, 0, "fmc", "ahb_div", + CLK_IGNORE_UNUSED }, + + { STM32F4_RCC_APB1ENR, 0, "tim2", "apb1_mul" }, + { STM32F4_RCC_APB1ENR, 1, "tim3", "apb1_mul" }, + { STM32F4_RCC_APB1ENR, 2, "tim4", "apb1_mul" }, + { STM32F4_RCC_APB1ENR, 3, "tim5", "apb1_mul" }, + { STM32F4_RCC_APB1ENR, 4, "tim6", "apb1_mul" }, + { STM32F4_RCC_APB1ENR, 5, "tim7", "apb1_mul" }, + { STM32F4_RCC_APB1ENR, 6, "tim12", "apb1_mul" }, + { STM32F4_RCC_APB1ENR, 7, "tim13", "apb1_mul" }, + { STM32F4_RCC_APB1ENR, 8, "tim14", "apb1_mul" }, + { STM32F4_RCC_APB1ENR, 11, "wwdg", "apb1_div" }, + { STM32F4_RCC_APB1ENR, 14, "spi2", "apb1_div" }, + { STM32F4_RCC_APB1ENR, 15, "spi3", "apb1_div" }, + { STM32F4_RCC_APB1ENR, 17, "uart2", "apb1_div" }, + { STM32F4_RCC_APB1ENR, 18, "uart3", "apb1_div" }, + { STM32F4_RCC_APB1ENR, 19, "uart4", "apb1_div" }, + { STM32F4_RCC_APB1ENR, 20, "uart5", "apb1_div" }, + { STM32F4_RCC_APB1ENR, 21, "i2c1", "apb1_div" }, + { STM32F4_RCC_APB1ENR, 22, "i2c2", "apb1_div" }, + { STM32F4_RCC_APB1ENR, 23, "i2c3", "apb1_div" }, + { STM32F4_RCC_APB1ENR, 25, "can1", "apb1_div" }, + { STM32F4_RCC_APB1ENR, 26, "can2", "apb1_div" }, + { STM32F4_RCC_APB1ENR, 28, "pwr", "apb1_div" }, + { STM32F4_RCC_APB1ENR, 29, "dac", "apb1_div" }, + { STM32F4_RCC_APB1ENR, 30, "uart7", "apb1_div" }, + { STM32F4_RCC_APB1ENR, 31, "uart8", "apb1_div" }, + + { STM32F4_RCC_APB2ENR, 0, "tim1", "apb2_mul" }, + { STM32F4_RCC_APB2ENR, 1, "tim8", "apb2_mul" }, + { STM32F4_RCC_APB2ENR, 4, "usart1", "apb2_div" }, + { STM32F4_RCC_APB2ENR, 5, "usart6", "apb2_div" }, + { STM32F4_RCC_APB2ENR, 8, "adc1", "apb2_div" }, + { STM32F4_RCC_APB2ENR, 9, "adc2", "apb2_div" }, + { STM32F4_RCC_APB2ENR, 10, "adc3", "apb2_div" }, + { STM32F4_RCC_APB2ENR, 11, "sdio", "pll48" }, + { STM32F4_RCC_APB2ENR, 12, "spi1", "apb2_div" }, + { STM32F4_RCC_APB2ENR, 13, "spi4", "apb2_div" }, + { STM32F4_RCC_APB2ENR, 14, "syscfg", "apb2_div" }, + { STM32F4_RCC_APB2ENR, 16, "tim9", "apb2_mul" }, + { STM32F4_RCC_APB2ENR, 17, "tim10", "apb2_mul" }, + { STM32F4_RCC_APB2ENR, 18, "tim11", "apb2_mul" }, + { STM32F4_RCC_APB2ENR, 20, "spi5", "apb2_div" }, + { STM32F4_RCC_APB2ENR, 21, "spi6", "apb2_div" }, + { STM32F4_RCC_APB2ENR, 22, "sai1", "apb2_div" }, + { STM32F4_RCC_APB2ENR, 26, "ltdc", "apb2_div" }, +}; + +/* + * MAX_CLKS is the maximum value in the enumeration below plus the combined + * hweight of stm32f42xx_gate_map (plus one). + */ +#define MAX_CLKS 74 + +enum { SYSTICK, FCLK }; + +/* + * This bitmask tells us which bit offsets (0..192) on STM32F4[23]xxx + * have gate bits associated with them. Its combined hweight is 71. + */ +static const u64 stm32f42xx_gate_map[] = { 0x000000f17ef417ffull, + 0x0000000000000001ull, + 0x04777f33f6fec9ffull }; + +static struct clk *clks[MAX_CLKS]; +static DEFINE_SPINLOCK(stm32f4_clk_lock); +static void __iomem *base; + +/* + * "Multiplier" device for APBx clocks. + * + * The APBx dividers are power-of-two dividers and, if *not* running in 1:1 + * mode, they also tap out the one of the low order state bits to run the + * timers. ST datasheets represent this feature as a (conditional) clock + * multiplier. + */ +struct clk_apb_mul { + struct clk_hw hw; + u8 bit_idx; +}; + +#define to_clk_apb_mul(_hw) container_of(_hw, struct clk_apb_mul, hw) + +static unsigned long clk_apb_mul_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct clk_apb_mul *am = to_clk_apb_mul(hw); + + if (readl(base + STM32F4_RCC_CFGR) & BIT(am->bit_idx)) + return parent_rate * 2; + + return parent_rate; +} + +static long clk_apb_mul_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *prate) +{ + struct clk_apb_mul *am = to_clk_apb_mul(hw); + unsigned long mult = 1; + + if (readl(base + STM32F4_RCC_CFGR) & BIT(am->bit_idx)) + mult = 2; + + if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) { + unsigned long best_parent = rate / mult; + + *prate = clk_hw_round_rate(clk_hw_get_parent(hw), best_parent); + } + + return *prate * mult; +} + +static int clk_apb_mul_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + /* + * We must report success but we can do so unconditionally because + * clk_apb_mul_round_rate returns values that ensure this call is a + * nop. + */ + + return 0; +} + +static const struct clk_ops clk_apb_mul_factor_ops = { + .round_rate = clk_apb_mul_round_rate, + .set_rate = clk_apb_mul_set_rate, + .recalc_rate = clk_apb_mul_recalc_rate, +}; + +static struct clk *clk_register_apb_mul(struct device *dev, const char *name, + const char *parent_name, + unsigned long flags, u8 bit_idx) +{ + struct clk_apb_mul *am; + struct clk_init_data init; + struct clk *clk; + + am = kzalloc(sizeof(*am), GFP_KERNEL); + if (!am) + return ERR_PTR(-ENOMEM); + + am->bit_idx = bit_idx; + am->hw.init = &init; + + init.name = name; + init.ops = &clk_apb_mul_factor_ops; + init.flags = flags; + init.parent_names = &parent_name; + init.num_parents = 1; + + clk = clk_register(dev, &am->hw); + + if (IS_ERR(clk)) + kfree(am); + + return clk; +} + +/* + * Decode current PLL state and (statically) model the state we inherit from + * the bootloader. + */ +static void stm32f4_rcc_register_pll(const char *hse_clk, const char *hsi_clk) +{ + unsigned long pllcfgr = readl(base + STM32F4_RCC_PLLCFGR); + + unsigned long pllm = pllcfgr & 0x3f; + unsigned long plln = (pllcfgr >> 6) & 0x1ff; + unsigned long pllp = BIT(((pllcfgr >> 16) & 3) + 1); + const char *pllsrc = pllcfgr & BIT(22) ? hse_clk : hsi_clk; + unsigned long pllq = (pllcfgr >> 24) & 0xf; + + clk_register_fixed_factor(NULL, "vco", pllsrc, 0, plln, pllm); + clk_register_fixed_factor(NULL, "pll", "vco", 0, 1, pllp); + clk_register_fixed_factor(NULL, "pll48", "vco", 0, 1, pllq); +} + +/* + * Converts the primary and secondary indices (as they appear in DT) to an + * offset into our struct clock array. + */ +static int stm32f4_rcc_lookup_clk_idx(u8 primary, u8 secondary) +{ + u64 table[ARRAY_SIZE(stm32f42xx_gate_map)]; + + if (primary == 1) { + if (WARN_ON(secondary > FCLK)) + return -EINVAL; + return secondary; + } + + memcpy(table, stm32f42xx_gate_map, sizeof(table)); + + /* only bits set in table can be used as indices */ + if (WARN_ON(secondary >= BITS_PER_BYTE * sizeof(table) || + 0 == (table[BIT_ULL_WORD(secondary)] & + BIT_ULL_MASK(secondary)))) + return -EINVAL; + + /* mask out bits above our current index */ + table[BIT_ULL_WORD(secondary)] &= + GENMASK_ULL(secondary % BITS_PER_LONG_LONG, 0); + + return FCLK + hweight64(table[0]) + + (BIT_ULL_WORD(secondary) >= 1 ? hweight64(table[1]) : 0) + + (BIT_ULL_WORD(secondary) >= 2 ? hweight64(table[2]) : 0); +} + +static struct clk * +stm32f4_rcc_lookup_clk(struct of_phandle_args *clkspec, void *data) +{ + int i = stm32f4_rcc_lookup_clk_idx(clkspec->args[0], clkspec->args[1]); + + if (i < 0) + return ERR_PTR(-EINVAL); + + return clks[i]; +} + +static const char *sys_parents[] __initdata = { "hsi", NULL, "pll" }; + +static const struct clk_div_table ahb_div_table[] = { + { 0x0, 1 }, { 0x1, 1 }, { 0x2, 1 }, { 0x3, 1 }, + { 0x4, 1 }, { 0x5, 1 }, { 0x6, 1 }, { 0x7, 1 }, + { 0x8, 2 }, { 0x9, 4 }, { 0xa, 8 }, { 0xb, 16 }, + { 0xc, 64 }, { 0xd, 128 }, { 0xe, 256 }, { 0xf, 512 }, + { 0 }, +}; + +static const struct clk_div_table apb_div_table[] = { + { 0, 1 }, { 0, 1 }, { 0, 1 }, { 0, 1 }, + { 4, 2 }, { 5, 4 }, { 6, 8 }, { 7, 16 }, + { 0 }, +}; + +static void __init stm32f4_rcc_init(struct device_node *np) +{ + const char *hse_clk; + int n; + + base = of_iomap(np, 0); + if (!base) { + pr_err("%s: unable to map resource", np->name); + return; + } + + hse_clk = of_clk_get_parent_name(np, 0); + + clk_register_fixed_rate_with_accuracy(NULL, "hsi", NULL, 0, + 16000000, 160000); + stm32f4_rcc_register_pll(hse_clk, "hsi"); + + sys_parents[1] = hse_clk; + clk_register_mux_table( + NULL, "sys", sys_parents, ARRAY_SIZE(sys_parents), 0, + base + STM32F4_RCC_CFGR, 0, 3, 0, NULL, &stm32f4_clk_lock); + + clk_register_divider_table(NULL, "ahb_div", "sys", + CLK_SET_RATE_PARENT, base + STM32F4_RCC_CFGR, + 4, 4, 0, ahb_div_table, &stm32f4_clk_lock); + + clk_register_divider_table(NULL, "apb1_div", "ahb_div", + CLK_SET_RATE_PARENT, base + STM32F4_RCC_CFGR, + 10, 3, 0, apb_div_table, &stm32f4_clk_lock); + clk_register_apb_mul(NULL, "apb1_mul", "apb1_div", + CLK_SET_RATE_PARENT, 12); + + clk_register_divider_table(NULL, "apb2_div", "ahb_div", + CLK_SET_RATE_PARENT, base + STM32F4_RCC_CFGR, + 13, 3, 0, apb_div_table, &stm32f4_clk_lock); + clk_register_apb_mul(NULL, "apb2_mul", "apb2_div", + CLK_SET_RATE_PARENT, 15); + + clks[SYSTICK] = clk_register_fixed_factor(NULL, "systick", "ahb_div", + 0, 1, 8); + clks[FCLK] = clk_register_fixed_factor(NULL, "fclk", "ahb_div", + 0, 1, 1); + + for (n = 0; n < ARRAY_SIZE(stm32f4_gates); n++) { + const struct stm32f4_gate_data *gd = &stm32f4_gates[n]; + unsigned int secondary = + 8 * (gd->offset - STM32F4_RCC_AHB1ENR) + gd->bit_idx; + int idx = stm32f4_rcc_lookup_clk_idx(0, secondary); + + if (idx < 0) + goto fail; + + clks[idx] = clk_register_gate( + NULL, gd->name, gd->parent_name, gd->flags, + base + gd->offset, gd->bit_idx, 0, &stm32f4_clk_lock); + + if (IS_ERR(clks[n])) { + pr_err("%s: Unable to register leaf clock %s\n", + np->full_name, gd->name); + goto fail; + } + } + + of_clk_add_provider(np, stm32f4_rcc_lookup_clk, NULL); + return; +fail: + iounmap(base); +} +CLK_OF_DECLARE(stm32f4_rcc, "st,stm32f42xx-rcc", stm32f4_rcc_init); |