- 根目录:
- drivers
- clk
- clk-stm32f4.c
/*
* 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);