gate.c
/*
* Clock driver for Keystone 2 based devices
*
* Copyright (C) 2013 Texas Instruments.
* Murali Karicheri <m-karicheri2@ti.com>
* Santosh Shilimkar <santosh.shilimkar@ti.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/clk-provider.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/of_address.h>
#include <linux/of.h>
#include <linux/module.h>
/* PSC register offsets */
#define PTCMD 0x120
#define PTSTAT 0x128
#define PDSTAT 0x200
#define PDCTL 0x300
#define MDSTAT 0x800
#define MDCTL 0xa00
/* PSC module states */
#define PSC_STATE_SWRSTDISABLE 0
#define PSC_STATE_SYNCRST 1
#define PSC_STATE_DISABLE 2
#define PSC_STATE_ENABLE 3
#define MDSTAT_STATE_MASK 0x3f
#define MDSTAT_MCKOUT BIT(12)
#define PDSTAT_STATE_MASK 0x1f
#define MDCTL_FORCE BIT(31)
#define MDCTL_LRESET BIT(8)
#define PDCTL_NEXT BIT(0)
/* Maximum timeout to bail out state transition for module */
#define STATE_TRANS_MAX_COUNT 0xffff
static void __iomem *domain_transition_base;
/**
* struct clk_psc_data - PSC data
* @control_base: Base address for a PSC control
* @domain_base: Base address for a PSC domain
* @domain_id: PSC domain id number
*/
struct clk_psc_data {
void __iomem *control_base;
void __iomem *domain_base;
u32 domain_id;
};
/**
* struct clk_psc - PSC clock structure
* @hw: clk_hw for the psc
* @psc_data: PSC driver specific data
* @lock: Spinlock used by the driver
*/
struct clk_psc {
struct clk_hw hw;
struct clk_psc_data *psc_data;
spinlock_t *lock;
};
static DEFINE_SPINLOCK(psc_lock);
#define to_clk_psc(_hw) container_of(_hw, struct clk_psc, hw)
static void psc_config(void __iomem *control_base, void __iomem *domain_base,
u32 next_state, u32 domain_id)
{
u32 ptcmd, pdstat, pdctl, mdstat, mdctl, ptstat;
u32 count = STATE_TRANS_MAX_COUNT;
mdctl = readl(control_base + MDCTL);
mdctl &= ~MDSTAT_STATE_MASK;
mdctl |= next_state;
/* For disable, we always put the module in local reset */
if (next_state == PSC_STATE_DISABLE)
mdctl &= ~MDCTL_LRESET;
writel(mdctl, control_base + MDCTL);
pdstat = readl(domain_base + PDSTAT);
if (!(pdstat & PDSTAT_STATE_MASK)) {
pdctl = readl(domain_base + PDCTL);
pdctl |= PDCTL_NEXT;
writel(pdctl, domain_base + PDCTL);
}
ptcmd = 1 << domain_id;
writel(ptcmd, domain_transition_base + PTCMD);
do {
ptstat = readl(domain_transition_base + PTSTAT);
} while (((ptstat >> domain_id) & 1) && count--);
count = STATE_TRANS_MAX_COUNT;
do {
mdstat = readl(control_base + MDSTAT);
} while (!((mdstat & MDSTAT_STATE_MASK) == next_state) && count--);
}
static int keystone_clk_is_enabled(struct clk_hw *hw)
{
struct clk_psc *psc = to_clk_psc(hw);
struct clk_psc_data *data = psc->psc_data;
u32 mdstat = readl(data->control_base + MDSTAT);
return (mdstat & MDSTAT_MCKOUT) ? 1 : 0;
}
static int keystone_clk_enable(struct clk_hw *hw)
{
struct clk_psc *psc = to_clk_psc(hw);
struct clk_psc_data *data = psc->psc_data;
unsigned long flags = 0;
if (psc->lock)
spin_lock_irqsave(psc->lock, flags);
psc_config(data->control_base, data->domain_base,
PSC_STATE_ENABLE, data->domain_id);
if (psc->lock)
spin_unlock_irqrestore(psc->lock, flags);
return 0;
}
static void keystone_clk_disable(struct clk_hw *hw)
{
struct clk_psc *psc = to_clk_psc(hw);
struct clk_psc_data *data = psc->psc_data;
unsigned long flags = 0;
if (psc->lock)
spin_lock_irqsave(psc->lock, flags);
psc_config(data->control_base, data->domain_base,
PSC_STATE_DISABLE, data->domain_id);
if (psc->lock)
spin_unlock_irqrestore(psc->lock, flags);
}
static const struct clk_ops clk_psc_ops = {
.enable = keystone_clk_enable,
.disable = keystone_clk_disable,
.is_enabled = keystone_clk_is_enabled,
};
/**
* clk_register_psc - register psc clock
* @dev: device that is registering this clock
* @name: name of this clock
* @parent_name: name of clock's parent
* @psc_data: platform data to configure this clock
* @lock: spinlock used by this clock
*/
static struct clk *clk_register_psc(struct device *dev,
const char *name,
const char *parent_name,
struct clk_psc_data *psc_data,
spinlock_t *lock)
{
struct clk_init_data init;
struct clk_psc *psc;
struct clk *clk;
psc = kzalloc(sizeof(*psc), GFP_KERNEL);
if (!psc)
return ERR_PTR(-ENOMEM);
init.name = name;
init.ops = &clk_psc_ops;
init.flags = 0;
init.parent_names = (parent_name ? &parent_name : NULL);
init.num_parents = (parent_name ? 1 : 0);
psc->psc_data = psc_data;
psc->lock = lock;
psc->hw.init = &init;
clk = clk_register(NULL, &psc->hw);
if (IS_ERR(clk))
kfree(psc);
return clk;
}
/**
* of_psc_clk_init - initialize psc clock through DT
* @node: device tree node for this clock
* @lock: spinlock used by this clock
*/
static void __init of_psc_clk_init(struct device_node *node, spinlock_t *lock)
{
const char *clk_name = node->name;
const char *parent_name;
struct clk_psc_data *data;
struct clk *clk;
int i;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data) {
pr_err("%s: Out of memory\n", __func__);
return;
}
i = of_property_match_string(node, "reg-names", "control");
data->control_base = of_iomap(node, i);
if (!data->control_base) {
pr_err("%s: control ioremap failed\n", __func__);
goto out;
}
i = of_property_match_string(node, "reg-names", "domain");
data->domain_base = of_iomap(node, i);
if (!data->domain_base) {
pr_err("%s: domain ioremap failed\n", __func__);
goto unmap_ctrl;
}
of_property_read_u32(node, "domain-id", &data->domain_id);
/* Domain transition registers at fixed address space of domain_id 0 */
if (!domain_transition_base && !data->domain_id)
domain_transition_base = data->domain_base;
of_property_read_string(node, "clock-output-names", &clk_name);
parent_name = of_clk_get_parent_name(node, 0);
if (!parent_name) {
pr_err("%s: Parent clock not found\n", __func__);
goto unmap_domain;
}
clk = clk_register_psc(NULL, clk_name, parent_name, data, lock);
if (!IS_ERR(clk)) {
of_clk_add_provider(node, of_clk_src_simple_get, clk);
return;
}
pr_err("%s: error registering clk %s\n", __func__, node->name);
unmap_domain:
iounmap(data->domain_base);
unmap_ctrl:
iounmap(data->control_base);
out:
kfree(data);
return;
}
/**
* of_keystone_psc_clk_init - initialize psc clock through DT
* @node: device tree node for this clock
*/
static void __init of_keystone_psc_clk_init(struct device_node *node)
{
of_psc_clk_init(node, &psc_lock);
}
CLK_OF_DECLARE(keystone_gate_clk, "ti,keystone,psc-clock",
of_keystone_psc_clk_init);