[PATCH] clk: qcom: Add support for RCG to register for DFS

From: Taniya Das
Date: Thu May 03 2018 - 00:13:28 EST


In the cases where a RCG requires a Dynamic Frequency switch support
requires to register which would at runtime read the clock perf level
registers to identify the frequencies supported and update the frequency
table accordingly.

Signed-off-by: Taniya Das <tdas@xxxxxxxxxxxxxx>
---
drivers/clk/qcom/clk-rcg.h | 7 +-
drivers/clk/qcom/clk-rcg2.c | 172 ++++++++++++++++++++++++++++++++++++++++++++
drivers/clk/qcom/common.c | 23 +++++-
drivers/clk/qcom/common.h | 14 +++-
4 files changed, 213 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/qcom/clk-rcg.h b/drivers/clk/qcom/clk-rcg.h
index 2a7489a..06de69f 100644
--- a/drivers/clk/qcom/clk-rcg.h
+++ b/drivers/clk/qcom/clk-rcg.h
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2013, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2013, 2018, The Linux Foundation. All rights reserved.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
@@ -144,6 +144,7 @@ struct clk_dyn_rcg {
* @cmd_rcgr: corresponds to *_CMD_RCGR
* @mnd_width: number of bits in m/n/d values
* @hid_width: number of bits in half integer divider
+ * @flags: additional flag parameters for the RCG
* @parent_map: map from software's parent index to hardware's src_sel field
* @freq_tbl: frequency table
* @clkr: regmap clock handle
@@ -153,6 +154,8 @@ struct clk_rcg2 {
u32 cmd_rcgr;
u8 mnd_width;
u8 hid_width;
+ u8 flags;
+#define DFS_ENABLE_RCG BIT(0)
const struct parent_map *parent_map;
const struct freq_tbl *freq_tbl;
struct clk_regmap clkr;
@@ -168,4 +171,6 @@ struct clk_rcg2 {
extern const struct clk_ops clk_pixel_ops;
extern const struct clk_ops clk_gfx3d_ops;

+extern int clk_rcg2_get_dfs_clock_rate(struct clk_rcg2 *clk,
+ struct device *dev);
#endif
diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c
index e63db10..7c35bca 100644
--- a/drivers/clk/qcom/clk-rcg2.c
+++ b/drivers/clk/qcom/clk-rcg2.c
@@ -18,6 +18,7 @@
#include <linux/export.h>
#include <linux/clk-provider.h>
#include <linux/delay.h>
+#include <linux/device.h>
#include <linux/regmap.h>
#include <linux/math64.h>

@@ -48,6 +49,14 @@
#define N_REG 0xc
#define D_REG 0x10

+/* Dynamic Frequency Scaling */
+#define MAX_PERF_LEVEL 16
+#define SE_CMD_DFSR_OFFSET 0x14
+#define SE_CMD_DFS_EN BIT(0)
+#define SE_PERF_DFSR(level) (0x1c + 0x4 * (level))
+#define SE_PERF_M_DFSR(level) (0x5c + 0x4 * (level))
+#define SE_PERF_N_DFSR(level) (0x9c + 0x4 * (level))
+
enum freq_policy {
FLOOR,
CEIL,
@@ -122,6 +131,10 @@ static int clk_rcg2_set_parent(struct clk_hw *hw, u8 index)
int ret;
u32 cfg = rcg->parent_map[index].cfg << CFG_SRC_SEL_SHIFT;

+ /* In DFS mode skip updating the RCG CFG */
+ if (rcg->flags & DFS_ENABLE_RCG)
+ return 0;
+
ret = regmap_update_bits(rcg->clkr.regmap, rcg->cmd_rcgr + CFG_REG,
CFG_SRC_SEL_MASK, cfg);
if (ret)
@@ -296,6 +309,9 @@ static int __clk_rcg2_set_rate(struct clk_hw *hw, unsigned long rate,
struct clk_rcg2 *rcg = to_clk_rcg2(hw);
const struct freq_tbl *f;

+ if (rcg->flags & DFS_ENABLE_RCG)
+ return -EPERM;
+
switch (policy) {
case FLOOR:
f = qcom_find_freq_floor(rcg->freq_tbl, rate);
@@ -790,3 +806,159 @@ static int clk_gfx3d_set_rate(struct clk_hw *hw, unsigned long rate,
.determine_rate = clk_gfx3d_determine_rate,
};
EXPORT_SYMBOL_GPL(clk_gfx3d_ops);
+
+/* Common APIs to be used for DFS based RCGR */
+static u8 clk_parent_index_pre_div_and_mode(struct clk_hw *hw, u32 offset,
+ u32 *mode, u32 *pre_div)
+{
+ struct clk_rcg2 *rcg;
+ int num_parents;
+ u32 cfg, mask;
+ int i, ret;
+
+ if (!hw)
+ return -EINVAL;
+
+ num_parents = clk_hw_get_num_parents(hw);
+
+ rcg = to_clk_rcg2(hw);
+
+ ret = regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + offset, &cfg);
+ if (ret)
+ goto err;
+
+ mask = BIT(rcg->hid_width) - 1;
+ *pre_div = cfg & mask ? (cfg & mask) : 1;
+
+ *mode = cfg & CFG_MODE_MASK;
+ *mode >>= CFG_MODE_SHIFT;
+
+ cfg &= CFG_SRC_SEL_MASK;
+ cfg >>= CFG_SRC_SEL_SHIFT;
+
+ for (i = 0; i < num_parents; i++)
+ if (cfg == rcg->parent_map[i].cfg)
+ return i;
+err:
+ return 0;
+}
+
+static int calculate_m_and_n(struct clk_hw *hw, u32 m_offset, u32 n_offset,
+ u32 mode, u32 *m, u32 *n)
+{
+ struct clk_rcg2 *rcg = to_clk_rcg2(hw);
+ u32 val, mask;
+ int ret = 0;
+
+ if (!hw)
+ return -EINVAL;
+
+ *m = *n = 0;
+
+ if (mode) {
+ /* Calculate M & N values */
+ mask = BIT(rcg->mnd_width) - 1;
+ ret = regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + m_offset,
+ &val);
+ if (ret) {
+ pr_err("Failed to read M offset register\n");
+ goto err;
+ }
+
+ val &= mask;
+ *m = val;
+
+ ret = regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + n_offset,
+ &val);
+ if (ret) {
+ pr_err("Failed to read N offset register\n");
+ goto err;
+ }
+
+ /* val ~(N-M) */
+ val = ~val;
+ val &= mask;
+ val += *m;
+ *n = val;
+ }
+err:
+ return ret;
+}
+
+int clk_rcg2_get_dfs_clock_rate(struct clk_rcg2 *clk, struct device *dev)
+{
+ int i, j, index, ret = 0;
+ unsigned long calc_freq, prate;
+ u32 val, pre_div = 0, mode = 0, m = 0, n = 0;
+ struct freq_tbl *dfs_freq_tbl;
+ struct clk_hw *phw;
+
+ if (!clk)
+ return -EINVAL;
+
+ /* Check for DFS_EN */
+ ret = regmap_read(clk->clkr.regmap, clk->cmd_rcgr + SE_CMD_DFSR_OFFSET,
+ &val);
+ if (ret) {
+ dev_err(dev, "Failed to read DFS enable register\n");
+ return -EINVAL;
+ }
+
+ if (!(val & SE_CMD_DFS_EN))
+ return ret;
+
+ dfs_freq_tbl = devm_kzalloc(dev, MAX_PERF_LEVEL *
+ sizeof(struct freq_tbl), GFP_KERNEL);
+ if (!dfs_freq_tbl)
+ return -ENOMEM;
+
+ /* Populate the Perf Level */
+ for (i = 0; i < MAX_PERF_LEVEL; i++) {
+ /* Get parent index and mode */
+ index = clk_parent_index_pre_div_and_mode(&clk->clkr.hw,
+ SE_PERF_DFSR(i), &mode,
+ &pre_div);
+ if (index < 0) {
+ pr_err("Failed to get parent index & mode %d\n", index);
+ return index;
+ }
+
+ /* clock pre_div */
+ dfs_freq_tbl[i].pre_div = pre_div;
+
+ /* Fill the parent src */
+ dfs_freq_tbl[i].src = clk->parent_map[index].src;
+
+ /* Get the parent clock and parent rate */
+ phw = clk_hw_get_parent_by_index(&clk->clkr.hw, index);
+ prate = clk_hw_get_rate(phw);
+
+ ret = calculate_m_and_n(&clk->clkr.hw, SE_PERF_M_DFSR(i),
+ SE_PERF_N_DFSR(i), mode, &m, &n);
+ if (ret)
+ goto err;
+
+ dfs_freq_tbl[i].m = m;
+ dfs_freq_tbl[i].n = n;
+
+ /* calculate the final frequency */
+ calc_freq = calc_rate(prate, dfs_freq_tbl[i].m,
+ dfs_freq_tbl[i].n, mode,
+ dfs_freq_tbl[i].pre_div);
+
+ /* Check for duplicate frequencies */
+ for (j = 0; j < i; j++) {
+ if (dfs_freq_tbl[j].freq == calc_freq)
+ goto done;
+ }
+
+ dfs_freq_tbl[i].freq = calc_freq;
+ }
+done:
+ j = i;
+
+ clk->flags |= DFS_ENABLE_RCG;
+ clk->freq_tbl = dfs_freq_tbl;
+err:
+ return ret;
+}
diff --git a/drivers/clk/qcom/common.c b/drivers/clk/qcom/common.c
index b8064a3..b27699b 100644
--- a/drivers/clk/qcom/common.c
+++ b/drivers/clk/qcom/common.c
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2013-2014, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2013-2014, 2018, The Linux Foundation. All rights reserved.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
@@ -288,4 +288,25 @@ int qcom_cc_probe(struct platform_device *pdev, const struct qcom_cc_desc *desc)
}
EXPORT_SYMBOL_GPL(qcom_cc_probe);

+int qcom_cc_register_rcg_dfs(struct platform_device *pdev,
+ const struct qcom_cc_dfs_desc *desc)
+{
+ struct clk_dfs *clks = desc->clks;
+ size_t num_clks = desc->num_clks;
+ int i, ret = 0;
+
+ for (i = 0; i < num_clks; i++) {
+ ret = clk_rcg2_get_dfs_clock_rate(clks[i].rcg, &pdev->dev);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "Failed calculating DFS frequencies for %s\n",
+ clk_hw_get_name(&(clks[i].rcg)->clkr.hw));
+ break;
+ }
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL(qcom_cc_register_rcg_dfs);
+
MODULE_LICENSE("GPL v2");
diff --git a/drivers/clk/qcom/common.h b/drivers/clk/qcom/common.h
index 00196ee..6627aec 100644
--- a/drivers/clk/qcom/common.h
+++ b/drivers/clk/qcom/common.h
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2014, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2014, 2018, The Linux Foundation. All rights reserved.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
@@ -48,6 +48,15 @@ struct parent_map {
u8 cfg;
};

+struct clk_dfs {
+ struct clk_rcg2 *rcg;
+};
+
+struct qcom_cc_dfs_desc {
+ struct clk_dfs *clks;
+ size_t num_clks;
+};
+
extern const struct freq_tbl *qcom_find_freq(const struct freq_tbl *f,
unsigned long rate);
extern const struct freq_tbl *qcom_find_freq_floor(const struct freq_tbl *f,
@@ -69,4 +78,7 @@ extern int qcom_cc_really_probe(struct platform_device *pdev,
extern int qcom_cc_probe(struct platform_device *pdev,
const struct qcom_cc_desc *desc);

+extern int qcom_cc_register_rcg_dfs(struct platform_device *pdev,
+ const struct qcom_cc_dfs_desc *desc);
+
#endif
--
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