linux_dsm_epyc7002/drivers/clk/baikal-t1/ccu-div.c

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clk: Add Baikal-T1 CCU Dividers driver Nearly each Baikal-T1 IP-core is supposed to have a clock source of particular frequency. But since there are greater than five IP-blocks embedded into the SoC, the CCU PLLs can't fulfill all the needs. Baikal-T1 CCU provides a set of fixed and configurable clock dividers in order to generate a necessary signal for each chip sub-block. This driver creates the of-based hardware clocks for each divider available in Baikal-T1 CCU. The same way as for PLLs we split the functionality up into the clocks operations (gate, ungate, set rate, etc) and hardware clocks declaration/registration procedures. In accordance with the CCU documentation all its dividers are distributed into two CCU sub-blocks: AXI-bus and system devices reference clocks. The former sub-block is used to supply the clocks for AXI-bus interfaces (AXI clock domains) and the later one provides the SoC IP-cores reference clocks. Each sub-block is represented by a dedicated DT node, so they have different compatible strings to distinguish one from another. For some reason CCU provides the dividers of different types. Some dividers can be gateable some can't, some are fixed while the others are variable, some have special divider' limitations, some've got a non-standard register layout and so on. In order to cover all of these cases the hardware clocks driver is designed with an info-descriptor pattern. So there are special static descriptors declared for the dividers of each type with additional flags describing the block peculiarity. These descriptors are then used to create hardware clocks with proper operations. Some CCU dividers provide a way to reset a domain they generate a clock for. So the CCU AXI-bus and CCU system devices clock drivers also perform the reset controller registration. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200526222056.18072-5-Sergey.Semin@baikalelectronics.ru [sboyd@kernel.org: Drop return from void function, silence sparse warnings about initializing structs with NULL vs. integer] Signed-off-by: Stephen Boyd <sboyd@kernel.org>
2020-05-27 05:20:56 +07:00
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
*
* Authors:
* Serge Semin <Sergey.Semin@baikalelectronics.ru>
* Dmitry Dunaev <dmitry.dunaev@baikalelectronics.ru>
*
* Baikal-T1 CCU Dividers interface driver
*/
#define pr_fmt(fmt) "bt1-ccu-div: " fmt
#include <linux/kernel.h>
#include <linux/printk.h>
#include <linux/bits.h>
#include <linux/bitfield.h>
#include <linux/slab.h>
#include <linux/clk-provider.h>
#include <linux/of.h>
#include <linux/spinlock.h>
#include <linux/regmap.h>
#include <linux/delay.h>
#include <linux/time64.h>
#include <linux/debugfs.h>
#include "ccu-div.h"
#define CCU_DIV_CTL 0x00
#define CCU_DIV_CTL_EN BIT(0)
#define CCU_DIV_CTL_RST BIT(1)
#define CCU_DIV_CTL_SET_CLKDIV BIT(2)
#define CCU_DIV_CTL_CLKDIV_FLD 4
#define CCU_DIV_CTL_CLKDIV_MASK(_width) \
GENMASK((_width) + CCU_DIV_CTL_CLKDIV_FLD - 1, CCU_DIV_CTL_CLKDIV_FLD)
#define CCU_DIV_CTL_LOCK_SHIFTED BIT(27)
#define CCU_DIV_CTL_LOCK_NORMAL BIT(31)
#define CCU_DIV_RST_DELAY_US 1
#define CCU_DIV_LOCK_CHECK_RETRIES 50
#define CCU_DIV_CLKDIV_MIN 0
#define CCU_DIV_CLKDIV_MAX(_mask) \
((_mask) >> CCU_DIV_CTL_CLKDIV_FLD)
/*
* Use the next two methods until there are generic field setter and
* getter available with non-constant mask support.
*/
static inline u32 ccu_div_get(u32 mask, u32 val)
{
return (val & mask) >> CCU_DIV_CTL_CLKDIV_FLD;
}
static inline u32 ccu_div_prep(u32 mask, u32 val)
{
return (val << CCU_DIV_CTL_CLKDIV_FLD) & mask;
}
static inline unsigned long ccu_div_lock_delay_ns(unsigned long ref_clk,
unsigned long div)
{
u64 ns = 4ULL * (div ?: 1) * NSEC_PER_SEC;
do_div(ns, ref_clk);
return ns;
}
static inline unsigned long ccu_div_calc_freq(unsigned long ref_clk,
unsigned long div)
{
return ref_clk / (div ?: 1);
}
static int ccu_div_var_update_clkdiv(struct ccu_div *div,
unsigned long parent_rate,
unsigned long divider)
{
unsigned long nd;
u32 val = 0;
u32 lock;
int count;
nd = ccu_div_lock_delay_ns(parent_rate, divider);
if (div->features & CCU_DIV_LOCK_SHIFTED)
lock = CCU_DIV_CTL_LOCK_SHIFTED;
else
lock = CCU_DIV_CTL_LOCK_NORMAL;
regmap_update_bits(div->sys_regs, div->reg_ctl,
CCU_DIV_CTL_SET_CLKDIV, CCU_DIV_CTL_SET_CLKDIV);
/*
* Until there is nsec-version of readl_poll_timeout() is available
* we have to implement the next polling loop.
*/
count = CCU_DIV_LOCK_CHECK_RETRIES;
do {
ndelay(nd);
regmap_read(div->sys_regs, div->reg_ctl, &val);
if (val & lock)
return 0;
} while (--count);
return -ETIMEDOUT;
}
static int ccu_div_var_enable(struct clk_hw *hw)
{
struct clk_hw *parent_hw = clk_hw_get_parent(hw);
struct ccu_div *div = to_ccu_div(hw);
unsigned long flags;
u32 val = 0;
int ret;
if (!parent_hw) {
pr_err("Can't enable '%s' with no parent", clk_hw_get_name(hw));
return -EINVAL;
}
regmap_read(div->sys_regs, div->reg_ctl, &val);
if (val & CCU_DIV_CTL_EN)
return 0;
spin_lock_irqsave(&div->lock, flags);
ret = ccu_div_var_update_clkdiv(div, clk_hw_get_rate(parent_hw),
ccu_div_get(div->mask, val));
if (!ret)
regmap_update_bits(div->sys_regs, div->reg_ctl,
CCU_DIV_CTL_EN, CCU_DIV_CTL_EN);
spin_unlock_irqrestore(&div->lock, flags);
if (ret)
pr_err("Divider '%s' lock timed out\n", clk_hw_get_name(hw));
return ret;
}
static int ccu_div_gate_enable(struct clk_hw *hw)
{
struct ccu_div *div = to_ccu_div(hw);
unsigned long flags;
spin_lock_irqsave(&div->lock, flags);
regmap_update_bits(div->sys_regs, div->reg_ctl,
CCU_DIV_CTL_EN, CCU_DIV_CTL_EN);
spin_unlock_irqrestore(&div->lock, flags);
return 0;
}
static void ccu_div_gate_disable(struct clk_hw *hw)
{
struct ccu_div *div = to_ccu_div(hw);
unsigned long flags;
spin_lock_irqsave(&div->lock, flags);
regmap_update_bits(div->sys_regs, div->reg_ctl, CCU_DIV_CTL_EN, 0);
spin_unlock_irqrestore(&div->lock, flags);
}
static int ccu_div_gate_is_enabled(struct clk_hw *hw)
{
struct ccu_div *div = to_ccu_div(hw);
u32 val = 0;
regmap_read(div->sys_regs, div->reg_ctl, &val);
return !!(val & CCU_DIV_CTL_EN);
}
static unsigned long ccu_div_var_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct ccu_div *div = to_ccu_div(hw);
unsigned long divider;
u32 val = 0;
regmap_read(div->sys_regs, div->reg_ctl, &val);
divider = ccu_div_get(div->mask, val);
return ccu_div_calc_freq(parent_rate, divider);
}
static inline unsigned long ccu_div_var_calc_divider(unsigned long rate,
unsigned long parent_rate,
unsigned int mask)
{
unsigned long divider;
divider = parent_rate / rate;
return clamp_t(unsigned long, divider, CCU_DIV_CLKDIV_MIN,
CCU_DIV_CLKDIV_MAX(mask));
}
static long ccu_div_var_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *parent_rate)
{
struct ccu_div *div = to_ccu_div(hw);
unsigned long divider;
divider = ccu_div_var_calc_divider(rate, *parent_rate, div->mask);
return ccu_div_calc_freq(*parent_rate, divider);
}
/*
* This method is used for the clock divider blocks, which support the
* on-the-fly rate change. So due to lacking the EN bit functionality
* they can't be gated before the rate adjustment.
*/
static int ccu_div_var_set_rate_slow(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct ccu_div *div = to_ccu_div(hw);
unsigned long flags, divider;
u32 val;
int ret;
divider = ccu_div_var_calc_divider(rate, parent_rate, div->mask);
if (divider == 1 && div->features & CCU_DIV_SKIP_ONE) {
divider = 0;
} else if (div->features & CCU_DIV_SKIP_ONE_TO_THREE) {
if (divider == 1 || divider == 2)
divider = 0;
else if (divider == 3)
divider = 4;
}
val = ccu_div_prep(div->mask, divider);
spin_lock_irqsave(&div->lock, flags);
regmap_update_bits(div->sys_regs, div->reg_ctl, div->mask, val);
ret = ccu_div_var_update_clkdiv(div, parent_rate, divider);
spin_unlock_irqrestore(&div->lock, flags);
if (ret)
pr_err("Divider '%s' lock timed out\n", clk_hw_get_name(hw));
return ret;
}
/*
* This method is used for the clock divider blocks, which don't support
* the on-the-fly rate change.
*/
static int ccu_div_var_set_rate_fast(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct ccu_div *div = to_ccu_div(hw);
unsigned long flags, divider = 1;
u32 val;
divider = ccu_div_var_calc_divider(rate, parent_rate, div->mask);
val = ccu_div_prep(div->mask, divider);
/*
* Also disable the clock divider block if it was enabled by default
* or by the bootloader.
*/
spin_lock_irqsave(&div->lock, flags);
regmap_update_bits(div->sys_regs, div->reg_ctl,
div->mask | CCU_DIV_CTL_EN, val);
spin_unlock_irqrestore(&div->lock, flags);
return 0;
}
static unsigned long ccu_div_fixed_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct ccu_div *div = to_ccu_div(hw);
return ccu_div_calc_freq(parent_rate, div->divider);
}
static long ccu_div_fixed_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *parent_rate)
{
struct ccu_div *div = to_ccu_div(hw);
return ccu_div_calc_freq(*parent_rate, div->divider);
}
static int ccu_div_fixed_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
return 0;
}
int ccu_div_reset_domain(struct ccu_div *div)
{
unsigned long flags;
if (!div || !(div->features & CCU_DIV_RESET_DOMAIN))
return -EINVAL;
spin_lock_irqsave(&div->lock, flags);
regmap_update_bits(div->sys_regs, div->reg_ctl,
CCU_DIV_CTL_RST, CCU_DIV_CTL_RST);
spin_unlock_irqrestore(&div->lock, flags);
/* The next delay must be enough to cover all the resets. */
udelay(CCU_DIV_RST_DELAY_US);
return 0;
}
#ifdef CONFIG_DEBUG_FS
struct ccu_div_dbgfs_bit {
struct ccu_div *div;
const char *name;
u32 mask;
};
#define CCU_DIV_DBGFS_BIT_ATTR(_name, _mask) { \
.name = _name, \
.mask = _mask \
}
static const struct ccu_div_dbgfs_bit ccu_div_bits[] = {
CCU_DIV_DBGFS_BIT_ATTR("div_en", CCU_DIV_CTL_EN),
CCU_DIV_DBGFS_BIT_ATTR("div_rst", CCU_DIV_CTL_RST),
CCU_DIV_DBGFS_BIT_ATTR("div_bypass", CCU_DIV_CTL_SET_CLKDIV),
CCU_DIV_DBGFS_BIT_ATTR("div_lock", CCU_DIV_CTL_LOCK_NORMAL)
};
#define CCU_DIV_DBGFS_BIT_NUM ARRAY_SIZE(ccu_div_bits)
/*
* It can be dangerous to change the Divider settings behind clock framework
* back, therefore we don't provide any kernel config based compile time option
* for this feature to enable.
*/
#undef CCU_DIV_ALLOW_WRITE_DEBUGFS
#ifdef CCU_DIV_ALLOW_WRITE_DEBUGFS
static int ccu_div_dbgfs_bit_set(void *priv, u64 val)
{
const struct ccu_div_dbgfs_bit *bit = priv;
struct ccu_div *div = bit->div;
unsigned long flags;
spin_lock_irqsave(&div->lock, flags);
regmap_update_bits(div->sys_regs, div->reg_ctl,
bit->mask, val ? bit->mask : 0);
spin_unlock_irqrestore(&div->lock, flags);
return 0;
}
static int ccu_div_dbgfs_var_clkdiv_set(void *priv, u64 val)
{
struct ccu_div *div = priv;
unsigned long flags;
u32 data;
val = clamp_t(u64, val, CCU_DIV_CLKDIV_MIN,
CCU_DIV_CLKDIV_MAX(div->mask));
data = ccu_div_prep(div->mask, val);
spin_lock_irqsave(&div->lock, flags);
regmap_update_bits(div->sys_regs, div->reg_ctl, div->mask, data);
spin_unlock_irqrestore(&div->lock, flags);
return 0;
}
#define ccu_div_dbgfs_mode 0644
#else /* !CCU_DIV_ALLOW_WRITE_DEBUGFS */
#define ccu_div_dbgfs_bit_set NULL
#define ccu_div_dbgfs_var_clkdiv_set NULL
#define ccu_div_dbgfs_mode 0444
#endif /* !CCU_DIV_ALLOW_WRITE_DEBUGFS */
static int ccu_div_dbgfs_bit_get(void *priv, u64 *val)
{
const struct ccu_div_dbgfs_bit *bit = priv;
struct ccu_div *div = bit->div;
u32 data = 0;
regmap_read(div->sys_regs, div->reg_ctl, &data);
*val = !!(data & bit->mask);
return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(ccu_div_dbgfs_bit_fops,
ccu_div_dbgfs_bit_get, ccu_div_dbgfs_bit_set, "%llu\n");
static int ccu_div_dbgfs_var_clkdiv_get(void *priv, u64 *val)
{
struct ccu_div *div = priv;
u32 data = 0;
regmap_read(div->sys_regs, div->reg_ctl, &data);
*val = ccu_div_get(div->mask, data);
return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(ccu_div_dbgfs_var_clkdiv_fops,
ccu_div_dbgfs_var_clkdiv_get, ccu_div_dbgfs_var_clkdiv_set, "%llu\n");
static int ccu_div_dbgfs_fixed_clkdiv_get(void *priv, u64 *val)
{
struct ccu_div *div = priv;
*val = div->divider;
return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(ccu_div_dbgfs_fixed_clkdiv_fops,
ccu_div_dbgfs_fixed_clkdiv_get, NULL, "%llu\n");
static void ccu_div_var_debug_init(struct clk_hw *hw, struct dentry *dentry)
{
struct ccu_div *div = to_ccu_div(hw);
struct ccu_div_dbgfs_bit *bits;
int didx, bidx, num = 2;
const char *name;
num += !!(div->flags & CLK_SET_RATE_GATE) +
!!(div->features & CCU_DIV_RESET_DOMAIN);
bits = kcalloc(num, sizeof(*bits), GFP_KERNEL);
if (!bits)
return;
for (didx = 0, bidx = 0; bidx < CCU_DIV_DBGFS_BIT_NUM; ++bidx) {
name = ccu_div_bits[bidx].name;
if (!(div->flags & CLK_SET_RATE_GATE) &&
!strcmp("div_en", name)) {
continue;
}
if (!(div->features & CCU_DIV_RESET_DOMAIN) &&
!strcmp("div_rst", name)) {
continue;
}
bits[didx] = ccu_div_bits[bidx];
bits[didx].div = div;
if (div->features & CCU_DIV_LOCK_SHIFTED &&
!strcmp("div_lock", name)) {
bits[didx].mask = CCU_DIV_CTL_LOCK_SHIFTED;
}
debugfs_create_file_unsafe(bits[didx].name, ccu_div_dbgfs_mode,
dentry, &bits[didx],
&ccu_div_dbgfs_bit_fops);
++didx;
}
debugfs_create_file_unsafe("div_clkdiv", ccu_div_dbgfs_mode, dentry,
div, &ccu_div_dbgfs_var_clkdiv_fops);
}
static void ccu_div_gate_debug_init(struct clk_hw *hw, struct dentry *dentry)
{
struct ccu_div *div = to_ccu_div(hw);
struct ccu_div_dbgfs_bit *bit;
bit = kmalloc(sizeof(*bit), GFP_KERNEL);
if (!bit)
return;
*bit = ccu_div_bits[0];
bit->div = div;
debugfs_create_file_unsafe(bit->name, ccu_div_dbgfs_mode, dentry, bit,
&ccu_div_dbgfs_bit_fops);
debugfs_create_file_unsafe("div_clkdiv", 0400, dentry, div,
&ccu_div_dbgfs_fixed_clkdiv_fops);
}
static void ccu_div_fixed_debug_init(struct clk_hw *hw, struct dentry *dentry)
{
struct ccu_div *div = to_ccu_div(hw);
debugfs_create_file_unsafe("div_clkdiv", 0400, dentry, div,
&ccu_div_dbgfs_fixed_clkdiv_fops);
}
#else /* !CONFIG_DEBUG_FS */
#define ccu_div_var_debug_init NULL
#define ccu_div_gate_debug_init NULL
#define ccu_div_fixed_debug_init NULL
#endif /* !CONFIG_DEBUG_FS */
static const struct clk_ops ccu_div_var_gate_to_set_ops = {
.enable = ccu_div_var_enable,
.disable = ccu_div_gate_disable,
.is_enabled = ccu_div_gate_is_enabled,
.recalc_rate = ccu_div_var_recalc_rate,
.round_rate = ccu_div_var_round_rate,
.set_rate = ccu_div_var_set_rate_fast,
.debug_init = ccu_div_var_debug_init
};
static const struct clk_ops ccu_div_var_nogate_ops = {
.recalc_rate = ccu_div_var_recalc_rate,
.round_rate = ccu_div_var_round_rate,
.set_rate = ccu_div_var_set_rate_slow,
.debug_init = ccu_div_var_debug_init
};
static const struct clk_ops ccu_div_gate_ops = {
.enable = ccu_div_gate_enable,
.disable = ccu_div_gate_disable,
.is_enabled = ccu_div_gate_is_enabled,
.recalc_rate = ccu_div_fixed_recalc_rate,
.round_rate = ccu_div_fixed_round_rate,
.set_rate = ccu_div_fixed_set_rate,
.debug_init = ccu_div_gate_debug_init
};
static const struct clk_ops ccu_div_fixed_ops = {
.recalc_rate = ccu_div_fixed_recalc_rate,
.round_rate = ccu_div_fixed_round_rate,
.set_rate = ccu_div_fixed_set_rate,
.debug_init = ccu_div_fixed_debug_init
};
struct ccu_div *ccu_div_hw_register(const struct ccu_div_init_data *div_init)
{
struct clk_parent_data parent_data = { };
struct clk_init_data hw_init = { };
struct ccu_div *div;
int ret;
if (!div_init)
return ERR_PTR(-EINVAL);
div = kzalloc(sizeof(*div), GFP_KERNEL);
if (!div)
return ERR_PTR(-ENOMEM);
/*
* Note since Baikal-T1 System Controller registers are MMIO-backed
* we won't check the regmap IO operations return status, because it
* must be zero anyway.
*/
div->hw.init = &hw_init;
div->id = div_init->id;
div->reg_ctl = div_init->base + CCU_DIV_CTL;
div->sys_regs = div_init->sys_regs;
div->flags = div_init->flags;
div->features = div_init->features;
spin_lock_init(&div->lock);
hw_init.name = div_init->name;
hw_init.flags = div_init->flags;
if (div_init->type == CCU_DIV_VAR) {
if (hw_init.flags & CLK_SET_RATE_GATE)
hw_init.ops = &ccu_div_var_gate_to_set_ops;
else
hw_init.ops = &ccu_div_var_nogate_ops;
div->mask = CCU_DIV_CTL_CLKDIV_MASK(div_init->width);
} else if (div_init->type == CCU_DIV_GATE) {
hw_init.ops = &ccu_div_gate_ops;
div->divider = div_init->divider;
} else if (div_init->type == CCU_DIV_FIXED) {
hw_init.ops = &ccu_div_fixed_ops;
div->divider = div_init->divider;
} else {
ret = -EINVAL;
goto err_free_div;
}
if (!div_init->parent_name) {
ret = -EINVAL;
goto err_free_div;
}
parent_data.fw_name = div_init->parent_name;
hw_init.parent_data = &parent_data;
hw_init.num_parents = 1;
ret = of_clk_hw_register(div_init->np, &div->hw);
if (ret)
goto err_free_div;
return div;
err_free_div:
kfree(div);
return ERR_PTR(ret);
}
void ccu_div_hw_unregister(struct ccu_div *div)
{
clk_hw_unregister(&div->hw);
kfree(div);
}