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 <t...@codeaurora.org>
---
 drivers/clk/qcom/clk-rcg.h  |   6 +
 drivers/clk/qcom/clk-rcg2.c | 272 ++++++++++++++++++++++++++++++++++++++++++++
 drivers/clk/qcom/common.c   |  22 ++++
 drivers/clk/qcom/common.h   |  18 +--
 4 files changed, 306 insertions(+), 12 deletions(-)

diff --git a/drivers/clk/qcom/clk-rcg.h b/drivers/clk/qcom/clk-rcg.h
index b209a2f..b5e5424 100644
--- a/drivers/clk/qcom/clk-rcg.h
+++ b/drivers/clk/qcom/clk-rcg.h
@@ -138,6 +138,7 @@ struct clk_dyn_rcg {
  * @parent_map: map from software's parent index to hardware's src_sel field
  * @freq_tbl: frequency table
  * @clkr: regmap clock handle
+ * @dfs_enable: corresponds to dfs mode enable
  *
  */
 struct clk_rcg2 {
@@ -148,6 +149,7 @@ struct clk_rcg2 {
        const struct parent_map *parent_map;
        const struct freq_tbl   *freq_tbl;
        struct clk_regmap       clkr;
+       bool                    dfs_enable;
 };

 #define to_clk_rcg2(_hw) container_of(to_clk_regmap(_hw), struct clk_rcg2, 
clkr)
@@ -160,5 +162,9 @@ struct clk_rcg2 {
 extern const struct clk_ops clk_pixel_ops;
 extern const struct clk_ops clk_gfx3d_ops;
 extern const struct clk_ops clk_rcg2_shared_ops;
+extern const struct clk_ops clk_rcg2_dfs_ops;
+
+extern int clk_rcg2_enable_dfs(struct clk_rcg2 *clk, struct device *dev);
+extern int clk_rcg2_dfs_determine_rate_lazy(struct clk_rcg2 *clk);

 #endif
diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c
index 52208d4..9112891 100644
--- a/drivers/clk/qcom/clk-rcg2.c
+++ b/drivers/clk/qcom/clk-rcg2.c
@@ -10,8 +10,10 @@
 #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>
+#include <linux/slab.h>

 #include <asm/div64.h>

@@ -40,6 +42,14 @@
 #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,
@@ -929,3 +939,265 @@ static void clk_rcg2_shared_disable(struct clk_hw *hw)
        .set_rate_and_parent = clk_rcg2_shared_set_rate_and_parent,
 };
 EXPORT_SYMBOL_GPL(clk_rcg2_shared_ops);
+
+/* Common APIs to be used for DFS based RCGR */
+struct dfs_table {
+       u8 src_index;
+       unsigned long prate;
+};
+
+static struct dfs_table *dfs_entry;
+
+static int clk_index_pre_div_and_mode(struct clk_hw *hw, u32 offset,
+               u32 *mode, u8 *pre_div)
+{
+       struct clk_rcg2 *rcg = to_clk_rcg2(hw);
+       int i, num_parents, ret;
+       u32 cfg, mask;
+
+       num_parents = clk_hw_get_num_parents(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,
+               struct freq_tbl *f)
+{
+       struct clk_rcg2 *rcg = to_clk_rcg2(hw);
+       u32 val, mask;
+       int ret;
+
+       /* 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");
+               return ret;
+       }
+
+       val &= mask;
+       f->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");
+               return ret;
+       }
+
+       /* val ~(N-M) */
+       val = ~val;
+       val &= mask;
+       val += f->m;
+       f->n = val;
+
+       return 0;
+}
+
+int clk_rcg2_dfs_determine_rate_lazy(struct clk_rcg2 *rcg)
+{
+       struct freq_tbl *dfs_freq_tbl;
+       int i, j, index, ret = 0;
+       unsigned long calc_freq, prate;
+       u32 mode = 0;
+
+       if (rcg->dfs_enable) {
+               pr_debug("DFS tables already populated\n");
+               return 0;
+       }
+
+       dfs_freq_tbl = kcalloc(MAX_PERF_LEVEL, sizeof(struct freq_tbl),
+                               GFP_KERNEL);
+       if (!dfs_freq_tbl)
+               return -ENOMEM;
+
+       /* Populate the Perf Level frequencies */
+       for (i = 0; i < MAX_PERF_LEVEL; i++) {
+               /* Get parent index and mode */
+               index = clk_index_pre_div_and_mode(&rcg->clkr.hw,
+                                               SE_PERF_DFSR(i), &mode,
+                                               &dfs_freq_tbl[i].pre_div);
+               if (index < 0) {
+                       pr_err("Failed to get parent index & mode %d\n", index);
+                       kzfree(dfs_freq_tbl);
+                       return index;
+               }
+
+               /* Fill parent src */
+               dfs_freq_tbl[i].src = rcg->parent_map[index].src;
+               prate = dfs_entry[index].prate;
+
+               if (mode) {
+                       ret = calculate_m_and_n(&rcg->clkr.hw,
+                                               SE_PERF_M_DFSR(i),
+                                               SE_PERF_N_DFSR(i),
+                                               &dfs_freq_tbl[i]);
+                       if (ret)
+                               goto err;
+               } else {
+                       dfs_freq_tbl[i].m = 0;
+                       dfs_freq_tbl[i].n = 0;
+               }
+
+               /* 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:
+       rcg->freq_tbl = dfs_freq_tbl;
+err:
+       return ret;
+}
+EXPORT_SYMBOL_GPL(clk_rcg2_dfs_determine_rate_lazy);
+
+static int _freq_tbl_determine_dfs_rate(struct clk_hw *hw)
+{
+       struct clk_rcg2 *rcg = to_clk_rcg2(hw);
+       struct clk_hw *phw;
+       int i, num_parents;
+
+       num_parents = clk_hw_get_num_parents(hw);
+
+       dfs_entry = kcalloc(num_parents, sizeof(struct dfs_table), GFP_KERNEL);
+       if (!dfs_entry)
+               return -ENOMEM;
+
+       for (i = 0; i < num_parents; i++) {
+               dfs_entry[i].src_index = rcg->parent_map[i].src;
+               if (rcg->parent_map[i].cfg == 7)
+                       break;
+               phw = clk_hw_get_parent_by_index(&rcg->clkr.hw, i);
+               if (!phw) {
+                       kzfree(dfs_entry);
+                       return -EINVAL;
+               }
+               dfs_entry[i].prate = clk_hw_get_rate(phw);
+       }
+
+       return 0;
+}
+
+static int clk_rcg2_dfs_determine_rate(struct clk_hw *hw,
+                                  struct clk_rate_request *req)
+{
+       struct clk_rcg2 *rcg = to_clk_rcg2(hw);
+       int ret;
+
+       if (!rcg->dfs_enable) {
+               ret = _freq_tbl_determine_dfs_rate(hw);
+               if (ret) {
+                       pr_err("Failed to setup DFS frequency table\n");
+                       return ret;
+               }
+
+               ret = clk_rcg2_dfs_determine_rate_lazy(rcg);
+               if (ret) {
+                       pr_err("Failed to update DFS tables\n");
+                       return ret;
+               }
+       }
+
+       return clk_rcg2_shared_ops.determine_rate(hw, req);
+}
+
+static int clk_rcg2_dfs_set_parent(struct clk_hw *hw, u8 index)
+{
+       struct clk_rcg2 *rcg = to_clk_rcg2(hw);
+
+       /* DFS hardware takes care of setting the parent */
+       if (rcg->dfs_enable)
+               return 0;
+
+       return clk_rcg2_shared_ops.set_parent(hw, index);
+}
+
+static int clk_rcg2_dfs_set_rate(struct clk_hw *hw, unsigned long rate,
+                                   unsigned long prate)
+{
+       struct clk_rcg2 *rcg = to_clk_rcg2(hw);
+
+       if (rcg->dfs_enable)
+               return 0;
+
+       return clk_rcg2_shared_ops.set_rate(hw, rate, prate);
+}
+
+static int clk_rcg2_dfs_set_rate_and_parent(struct clk_hw *hw,
+                                   unsigned long rate,
+                                   unsigned long prate, u8 index)
+{
+       struct clk_rcg2 *rcg = to_clk_rcg2(hw);
+
+       if (rcg->dfs_enable)
+               return 0;
+
+       return clk_rcg2_shared_ops.set_rate_and_parent(hw, rate, prate, index);
+}
+
+const struct clk_ops clk_rcg2_dfs_ops = {
+       .is_enabled = clk_rcg2_is_enabled,
+       .get_parent = clk_rcg2_get_parent,
+       .set_parent = clk_rcg2_dfs_set_parent,
+       .recalc_rate = clk_rcg2_recalc_rate,
+       .determine_rate = clk_rcg2_dfs_determine_rate,
+       .set_rate = clk_rcg2_dfs_set_rate,
+       .set_rate_and_parent = clk_rcg2_dfs_set_rate_and_parent,
+};
+EXPORT_SYMBOL_GPL(clk_rcg2_dfs_ops);
+
+int clk_rcg2_enable_dfs(struct clk_rcg2 *rcg, struct device *dev)
+{
+       struct regmap *regmap;
+       struct clk_rate_request req = { };
+       u32 val;
+       int ret;
+
+       regmap = dev_get_regmap(dev, NULL);
+       if (!regmap)
+               return -EINVAL;
+
+       /* Check for DFS_EN */
+       ret = regmap_read(regmap, rcg->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;
+
+       ret = __clk_determine_rate(&rcg->clkr.hw, &req);
+       if (ret)
+               return ret;
+
+       rcg->dfs_enable = true;
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(clk_rcg2_enable_dfs);
diff --git a/drivers/clk/qcom/common.c b/drivers/clk/qcom/common.c
index b8064a3..0b656ed 100644
--- a/drivers/clk/qcom/common.c
+++ b/drivers/clk/qcom/common.c
@@ -288,4 +288,26 @@ 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,
+                           struct clk_rcg2 **rcgs, int num_clks)
+{
+       struct clk_rcg2 *rcg;
+       int i, ret = 0;
+
+       for (i = 0; i < num_clks; i++) {
+               rcg = rcgs[i];
+               ret = clk_rcg2_enable_dfs(rcg, &pdev->dev);
+               if (ret) {
+                       const char *name = (rcg->clkr.hw.init->name);
+
+                       dev_err(&pdev->dev,
+                               "%s DFS frequencies update failed\n", name);
+                       break;
+               }
+       }
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(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..71d1c27 100644
--- a/drivers/clk/qcom/common.h
+++ b/drivers/clk/qcom/common.h
@@ -1,15 +1,6 @@
-/*
- * Copyright (c) 2014, 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
- * may be copied, distributed, and modified under those terms.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- */
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) 2014, 2018, The Linux Foundation. All rights reserved. */
+
 #ifndef __QCOM_CLK_COMMON_H__
 #define __QCOM_CLK_COMMON_H__

@@ -20,6 +11,7 @@
 struct regmap;
 struct freq_tbl;
 struct clk_hw;
+struct clk_rcg2;

 #define PLL_LOCK_COUNT_SHIFT   8
 #define PLL_LOCK_COUNT_MASK    0x3f
@@ -69,4 +61,6 @@ 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,
+                                  struct clk_rcg2 **rcgs, int num_clks);
 #endif
--
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