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/*
* Hi6220 stub clock driver
*
* Copyright (c) 2015 Hisilicon Limited.
* Copyright (c) 2015 Linaro Limited.
*
* Author: Leo Yan <leo.yan@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/clk-provider.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/mailbox_client.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/regmap.h>
/* Stub clocks id */
#define HI6220_STUB_ACPU0 0
#define HI6220_STUB_ACPU1 1
#define HI6220_STUB_GPU 2
#define HI6220_STUB_DDR 5
/* Mailbox message */
#define HI6220_MBOX_MSG_LEN 8
#define HI6220_MBOX_FREQ 0xA
#define HI6220_MBOX_CMD_SET 0x3
#define HI6220_MBOX_OBJ_AP 0x0
/* CPU dynamic frequency scaling */
#define ACPU_DFS_FREQ_MAX 0x1724
#define ACPU_DFS_CUR_FREQ 0x17CC
#define ACPU_DFS_FLAG 0x1B30
#define ACPU_DFS_FREQ_REQ 0x1B34
#define ACPU_DFS_FREQ_LMT 0x1B38
#define ACPU_DFS_LOCK_FLAG 0xAEAEAEAE
#define to_stub_clk(hw) container_of(hw, struct hi6220_stub_clk, hw)
struct hi6220_stub_clk {
u32 id;
struct device *dev;
struct clk_hw hw;
struct regmap *dfs_map;
struct mbox_client cl;
struct mbox_chan *mbox;
};
struct hi6220_mbox_msg {
unsigned char type;
unsigned char cmd;
unsigned char obj;
unsigned char src;
unsigned char para[4];
};
union hi6220_mbox_data {
unsigned int data[HI6220_MBOX_MSG_LEN];
struct hi6220_mbox_msg msg;
};
static unsigned int hi6220_acpu_get_freq(struct hi6220_stub_clk *stub_clk)
{
unsigned int freq;
regmap_read(stub_clk->dfs_map, ACPU_DFS_CUR_FREQ, &freq);
return freq;
}
static int hi6220_acpu_set_freq(struct hi6220_stub_clk *stub_clk,
unsigned int freq)
{
union hi6220_mbox_data data;
/* set the frequency in sram */
regmap_write(stub_clk->dfs_map, ACPU_DFS_FREQ_REQ, freq);
/* compound mailbox message */
data.msg.type = HI6220_MBOX_FREQ;
data.msg.cmd = HI6220_MBOX_CMD_SET;
data.msg.obj = HI6220_MBOX_OBJ_AP;
data.msg.src = HI6220_MBOX_OBJ_AP;
mbox_send_message(stub_clk->mbox, &data);
return 0;
}
static int hi6220_acpu_round_freq(struct hi6220_stub_clk *stub_clk,
unsigned int freq)
{
unsigned int limit_flag, limit_freq = UINT_MAX;
unsigned int max_freq;
/* check the constrained frequency */
regmap_read(stub_clk->dfs_map, ACPU_DFS_FLAG, &limit_flag);
if (limit_flag == ACPU_DFS_LOCK_FLAG)
regmap_read(stub_clk->dfs_map, ACPU_DFS_FREQ_LMT, &limit_freq);
/* check the supported maximum frequency */
regmap_read(stub_clk->dfs_map, ACPU_DFS_FREQ_MAX, &max_freq);
/* calculate the real maximum frequency */
max_freq = min(max_freq, limit_freq);
if (WARN_ON(freq > max_freq))
freq = max_freq;
return freq;
}
static unsigned long hi6220_stub_clk_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
u32 rate = 0;
struct hi6220_stub_clk *stub_clk = to_stub_clk(hw);
switch (stub_clk->id) {
case HI6220_STUB_ACPU0:
rate = hi6220_acpu_get_freq(stub_clk);
/* convert from kHz to Hz */
rate *= 1000;
break;
default:
dev_err(stub_clk->dev, "%s: un-supported clock id %d\n",
__func__, stub_clk->id);
break;
}
return rate;
}
static int hi6220_stub_clk_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct hi6220_stub_clk *stub_clk = to_stub_clk(hw);
unsigned long new_rate = rate / 1000; /* kHz */
int ret = 0;
switch (stub_clk->id) {
case HI6220_STUB_ACPU0:
ret = hi6220_acpu_set_freq(stub_clk, new_rate);
if (ret < 0)
return ret;
break;
default:
dev_err(stub_clk->dev, "%s: un-supported clock id %d\n",
__func__, stub_clk->id);
break;
}
pr_debug("%s: set rate=%ldkHz\n", __func__, new_rate);
return ret;
}
static long hi6220_stub_clk_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *parent_rate)
{
struct hi6220_stub_clk *stub_clk = to_stub_clk(hw);
unsigned long new_rate = rate / 1000; /* kHz */
switch (stub_clk->id) {
case HI6220_STUB_ACPU0:
new_rate = hi6220_acpu_round_freq(stub_clk, new_rate);
/* convert from kHz to Hz */
new_rate *= 1000;
break;
default:
dev_err(stub_clk->dev, "%s: un-supported clock id %d\n",
__func__, stub_clk->id);
break;
}
return new_rate;
}
static const struct clk_ops hi6220_stub_clk_ops = {
.recalc_rate = hi6220_stub_clk_recalc_rate,
.round_rate = hi6220_stub_clk_round_rate,
.set_rate = hi6220_stub_clk_set_rate,
};
static int hi6220_stub_clk_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct clk_init_data init;
struct hi6220_stub_clk *stub_clk;
struct clk *clk;
struct device_node *np = pdev->dev.of_node;
int ret;
stub_clk = devm_kzalloc(dev, sizeof(*stub_clk), GFP_KERNEL);
if (!stub_clk)
return -ENOMEM;
stub_clk->dfs_map = syscon_regmap_lookup_by_phandle(np,
"hisilicon,hi6220-clk-sram");
if (IS_ERR(stub_clk->dfs_map)) {
dev_err(dev, "failed to get sram regmap\n");
return PTR_ERR(stub_clk->dfs_map);
}
stub_clk->hw.init = &init;
stub_clk->dev = dev;
stub_clk->id = HI6220_STUB_ACPU0;
/* Use mailbox client with blocking mode */
stub_clk->cl.dev = dev;
stub_clk->cl.tx_done = NULL;
stub_clk->cl.tx_block = true;
stub_clk->cl.tx_tout = 500;
stub_clk->cl.knows_txdone = false;
/* Allocate mailbox channel */
stub_clk->mbox = mbox_request_channel(&stub_clk->cl, 0);
if (IS_ERR(stub_clk->mbox)) {
dev_err(dev, "failed get mailbox channel\n");
return PTR_ERR(stub_clk->mbox);
}
init.name = "acpu0";
init.ops = &hi6220_stub_clk_ops;
init.num_parents = 0;
init.flags = 0;
clk = devm_clk_register(dev, &stub_clk->hw);
if (IS_ERR(clk))
return PTR_ERR(clk);
ret = of_clk_add_provider(np, of_clk_src_simple_get, clk);
if (ret) {
dev_err(dev, "failed to register OF clock provider\n");
return ret;
}
/* initialize buffer to zero */
regmap_write(stub_clk->dfs_map, ACPU_DFS_FLAG, 0x0);
regmap_write(stub_clk->dfs_map, ACPU_DFS_FREQ_REQ, 0x0);
regmap_write(stub_clk->dfs_map, ACPU_DFS_FREQ_LMT, 0x0);
dev_dbg(dev, "Registered clock '%s'\n", init.name);
return 0;
}
static const struct of_device_id hi6220_stub_clk_of_match[] = {
{ .compatible = "hisilicon,hi6220-stub-clk", },
{}
};
static struct platform_driver hi6220_stub_clk_driver = {
.driver = {
.name = "hi6220-stub-clk",
.of_match_table = hi6220_stub_clk_of_match,
},
.probe = hi6220_stub_clk_probe,
};
static int __init hi6220_stub_clk_init(void)
{
return platform_driver_register(&hi6220_stub_clk_driver);
}
subsys_initcall(hi6220_stub_clk_init);
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