--- /dev/null
+/*
+ * 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 = CLK_IS_ROOT;
+
+ 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);
Code Review / kvmfornfv.git / blobdiff