Re: [PATCH v3 1/2] clk: qcom: Add support for RCG to register for DFS
Quoting Taniya Das (2018-07-15 22:37:47)
> diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c
> index 52208d4..f8f1417 100644
> --- a/drivers/clk/qcom/clk-rcg2.c
> +++ b/drivers/clk/qcom/clk-rcg2.c
> @@ -929,3 +938,167 @@ 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 */
> +static unsigned long clk_rcg2_calculate_freq(struct clk_hw *hw,
> + int level, struct freq_tbl *f)
> +{
> + struct clk_rcg2 *rcg = to_clk_rcg2(hw);
> + struct clk_hw *p;
> + unsigned long prate = 0;
> + u32 val, mask, cfg, m_off, n_off, offset, mode;
> + int i, ret, num_parents;
> +
> + offset = SE_PERF_DFSR(level);
> + ret = regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + offset, );
> + if (ret)
> + return ret;
> +
> + mask = BIT(rcg->hid_width) - 1;
> + f->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;
> +
> + num_parents = clk_hw_get_num_parents(hw);
> + for (i = 0; i < num_parents; i++) {
> + if (cfg == rcg->parent_map[i].cfg) {
> + f->src = rcg->parent_map[i].src;
> + p = clk_hw_get_parent_by_index(>clkr.hw, i);
> + prate = clk_hw_get_rate(p);
> + }
> + }
> +
> + if (!mode)
> + goto done;
Please remove the goto and indent all the below code when we need to do
the mode check.
> +
> + /* Calculate M & N values */
> + m_off = SE_PERF_M_DFSR(level);
> + n_off = SE_PERF_N_DFSR(level);
> +
> + mask = BIT(rcg->mnd_width) - 1;
> + ret = regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + m_off, );
> + 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_off, );
> + 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;
> +done:
> + return calc_rate(prate, f->m, f->n, mode, f->pre_div);
> +}
> +
> +static int clk_rcg2_dfs_populate_freq_table(struct clk_rcg2 *rcg)
> +{
> + struct freq_tbl *freq_tbl;
> + unsigned long calc_freq;
> + int i;
> +
> + freq_tbl = kcalloc(MAX_PERF_LEVEL, sizeof(*freq_tbl),
> + GFP_KERNEL);
> + if (!freq_tbl)
> + return -ENOMEM;
> +
> + for (i = 0; i < MAX_PERF_LEVEL; i++) {
> + calc_freq = clk_rcg2_calculate_freq(>clkr.hw,
> + i, _tbl[i]);
> + if (calc_freq < 0) {
> + kfree(freq_tbl);
> + return calc_freq;
> + }
> +
> + freq_tbl[i].freq = calc_freq;
> + }
> + rcg->freq_tbl = freq_tbl;
> +
> + 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->freq_tbl) {
> + ret = clk_rcg2_dfs_populate_freq_table(rcg);
> + if (ret) {
> + pr_err("Failed to update DFS tables for %s\n",
> + clk_hw_get_name(hw));
> + return ret;
> + }
> + }
> +
> + return clk_rcg2_shared_ops.determine_rate(hw, req);
> +}
> +
> +static const struct clk_ops clk_rcg2_dfs_ops = {
> + .is_enabled = clk_rcg2_is_enabled,
> + .get_parent = clk_rcg2_get_parent,
> + .determine_rate = clk_rcg2_dfs_determine_rate,
It seems very risky to do this without being able to read the frequency
out of the hardware. Taking a peek at the DFS registers I see that there
is some sort of 'CURR_PERF_STATE' field in the DFSR register. Wouldn't
that correspond to the index in the table that the clk is currently
using? Why can't we mark these clks as CLK_GET_RATE_NOCACHE and then
read this field when we're using DFS?
In fact, I just tested this on my device and I see that changing the DFS
bit on the QUP register that controls the DFS used causes the DFSR
register in GCC to update the CURR_PERF_STATE field to match what is
chosen in the QUP. So there is definitely a way to implement
recalc_rate() for this clk. Please do so.
> +};
> +
> +static int clk_rcg2_enable_dfs(struct clk_rcg2 *rcg, struct regmap *regmap)
> +{
> + struct clk_init_data
Re: [PATCH v3 1/2] clk: qcom: Add support for RCG to register for DFS
Quoting Taniya Das (2018-07-15 22:37:47)
> diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c
> index 52208d4..f8f1417 100644
> --- a/drivers/clk/qcom/clk-rcg2.c
> +++ b/drivers/clk/qcom/clk-rcg2.c
> @@ -929,3 +938,167 @@ 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 */
> +static unsigned long clk_rcg2_calculate_freq(struct clk_hw *hw,
> + int level, struct freq_tbl *f)
> +{
> + struct clk_rcg2 *rcg = to_clk_rcg2(hw);
> + struct clk_hw *p;
> + unsigned long prate = 0;
> + u32 val, mask, cfg, m_off, n_off, offset, mode;
> + int i, ret, num_parents;
> +
> + offset = SE_PERF_DFSR(level);
> + ret = regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + offset, );
> + if (ret)
> + return ret;
> +
> + mask = BIT(rcg->hid_width) - 1;
> + f->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;
> +
> + num_parents = clk_hw_get_num_parents(hw);
> + for (i = 0; i < num_parents; i++) {
> + if (cfg == rcg->parent_map[i].cfg) {
> + f->src = rcg->parent_map[i].src;
> + p = clk_hw_get_parent_by_index(>clkr.hw, i);
> + prate = clk_hw_get_rate(p);
> + }
> + }
> +
> + if (!mode)
> + goto done;
Please remove the goto and indent all the below code when we need to do
the mode check.
> +
> + /* Calculate M & N values */
> + m_off = SE_PERF_M_DFSR(level);
> + n_off = SE_PERF_N_DFSR(level);
> +
> + mask = BIT(rcg->mnd_width) - 1;
> + ret = regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + m_off, );
> + 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_off, );
> + 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;
> +done:
> + return calc_rate(prate, f->m, f->n, mode, f->pre_div);
> +}
> +
> +static int clk_rcg2_dfs_populate_freq_table(struct clk_rcg2 *rcg)
> +{
> + struct freq_tbl *freq_tbl;
> + unsigned long calc_freq;
> + int i;
> +
> + freq_tbl = kcalloc(MAX_PERF_LEVEL, sizeof(*freq_tbl),
> + GFP_KERNEL);
> + if (!freq_tbl)
> + return -ENOMEM;
> +
> + for (i = 0; i < MAX_PERF_LEVEL; i++) {
> + calc_freq = clk_rcg2_calculate_freq(>clkr.hw,
> + i, _tbl[i]);
> + if (calc_freq < 0) {
> + kfree(freq_tbl);
> + return calc_freq;
> + }
> +
> + freq_tbl[i].freq = calc_freq;
> + }
> + rcg->freq_tbl = freq_tbl;
> +
> + 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->freq_tbl) {
> + ret = clk_rcg2_dfs_populate_freq_table(rcg);
> + if (ret) {
> + pr_err("Failed to update DFS tables for %s\n",
> + clk_hw_get_name(hw));
> + return ret;
> + }
> + }
> +
> + return clk_rcg2_shared_ops.determine_rate(hw, req);
> +}
> +
> +static const struct clk_ops clk_rcg2_dfs_ops = {
> + .is_enabled = clk_rcg2_is_enabled,
> + .get_parent = clk_rcg2_get_parent,
> + .determine_rate = clk_rcg2_dfs_determine_rate,
It seems very risky to do this without being able to read the frequency
out of the hardware. Taking a peek at the DFS registers I see that there
is some sort of 'CURR_PERF_STATE' field in the DFSR register. Wouldn't
that correspond to the index in the table that the clk is currently
using? Why can't we mark these clks as CLK_GET_RATE_NOCACHE and then
read this field when we're using DFS?
In fact, I just tested this on my device and I see that changing the DFS
bit on the QUP register that controls the DFS used causes the DFSR
register in GCC to update the CURR_PERF_STATE field to match what is
chosen in the QUP. So there is definitely a way to implement
recalc_rate() for this clk. Please do so.
> +};
> +
> +static int clk_rcg2_enable_dfs(struct clk_rcg2 *rcg, struct regmap *regmap)
> +{
> + struct clk_init_data
[PATCH v3 1/2] clk: qcom: Add support for RCG to register for DFS
Dynamic Frequency switch is a feature of clock controller by which request
from peripherals allows automatic switching frequency of input clock
without SW intervention. There are various performance levels associated
with a root clock. When the input performance state changes, the source
clocks and division ratios of the new performance state are loaded on to
RCG via HW and the RCG switches to new clock frequency when the RCG is in
DFS HW enabled mode.
Register the root clock generators(RCG) to switch to use the dfs clock ops
in the cases where DFS is enabled. The clk_round_rate() called by the clock
consumer would invoke the dfs determine clock ops and would read the DFS
performance level registers to identify all the frequencies supported and
update the frequency table. The DFS clock consumers would maintain these
frequency mapping and request the desired performance levels.
Signed-off-by: Taniya Das
---
drivers/clk/qcom/clk-rcg.h | 2 +
drivers/clk/qcom/clk-rcg2.c | 173
2 files changed, 175 insertions(+)
diff --git a/drivers/clk/qcom/clk-rcg.h b/drivers/clk/qcom/clk-rcg.h
index b209a2f..bffb625 100644
--- a/drivers/clk/qcom/clk-rcg.h
+++ b/drivers/clk/qcom/clk-rcg.h
@@ -161,4 +161,6 @@ struct clk_rcg2 {
extern const struct clk_ops clk_gfx3d_ops;
extern const struct clk_ops clk_rcg2_shared_ops;
+extern int qcom_cc_register_rcg_dfs(struct regmap *regmap,
+struct clk_rcg2 **rcgs, int num_clks);
#endif
diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c
index 52208d4..f8f1417 100644
--- a/drivers/clk/qcom/clk-rcg2.c
+++ b/drivers/clk/qcom/clk-rcg2.c
@@ -12,6 +12,7 @@
#include
#include
#include
+#include
#include
@@ -40,6 +41,14 @@
#define N_REG 0xc
#define D_REG 0x10
+/* Dynamic Frequency Scaling */
+#define MAX_PERF_LEVEL 8
+#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 +938,167 @@ 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 */
+static unsigned long clk_rcg2_calculate_freq(struct clk_hw *hw,
+ int level, struct freq_tbl *f)
+{
+ struct clk_rcg2 *rcg = to_clk_rcg2(hw);
+ struct clk_hw *p;
+ unsigned long prate = 0;
+ u32 val, mask, cfg, m_off, n_off, offset, mode;
+ int i, ret, num_parents;
+
+ offset = SE_PERF_DFSR(level);
+ ret = regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + offset, );
+ if (ret)
+ return ret;
+
+ mask = BIT(rcg->hid_width) - 1;
+ f->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;
+
+ num_parents = clk_hw_get_num_parents(hw);
+ for (i = 0; i < num_parents; i++) {
+ if (cfg == rcg->parent_map[i].cfg) {
+ f->src = rcg->parent_map[i].src;
+ p = clk_hw_get_parent_by_index(>clkr.hw, i);
+ prate = clk_hw_get_rate(p);
+ }
+ }
+
+ if (!mode)
+ goto done;
+
+ /* Calculate M & N values */
+ m_off = SE_PERF_M_DFSR(level);
+ n_off = SE_PERF_N_DFSR(level);
+
+ mask = BIT(rcg->mnd_width) - 1;
+ ret = regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + m_off, );
+ 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_off, );
+ 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;
+done:
+ return calc_rate(prate, f->m, f->n, mode, f->pre_div);
+}
+
+static int clk_rcg2_dfs_populate_freq_table(struct clk_rcg2 *rcg)
+{
+ struct freq_tbl *freq_tbl;
+ unsigned long calc_freq;
+ int i;
+
+ freq_tbl = kcalloc(MAX_PERF_LEVEL, sizeof(*freq_tbl),
+ GFP_KERNEL);
+ if (!freq_tbl)
+ return -ENOMEM;
+
+ for (i = 0; i < MAX_PERF_LEVEL; i++) {
+ calc_freq = clk_rcg2_calculate_freq(>clkr.hw,
+ i, _tbl[i]);
+ if (calc_freq < 0) {
+ kfree(freq_tbl);
+ return calc_freq;
+ }
+
+ freq_tbl[i].freq = calc_freq;
[PATCH v3 1/2] clk: qcom: Add support for RCG to register for DFS
Dynamic Frequency switch is a feature of clock controller by which request
from peripherals allows automatic switching frequency of input clock
without SW intervention. There are various performance levels associated
with a root clock. When the input performance state changes, the source
clocks and division ratios of the new performance state are loaded on to
RCG via HW and the RCG switches to new clock frequency when the RCG is in
DFS HW enabled mode.
Register the root clock generators(RCG) to switch to use the dfs clock ops
in the cases where DFS is enabled. The clk_round_rate() called by the clock
consumer would invoke the dfs determine clock ops and would read the DFS
performance level registers to identify all the frequencies supported and
update the frequency table. The DFS clock consumers would maintain these
frequency mapping and request the desired performance levels.
Signed-off-by: Taniya Das
---
drivers/clk/qcom/clk-rcg.h | 2 +
drivers/clk/qcom/clk-rcg2.c | 173
2 files changed, 175 insertions(+)
diff --git a/drivers/clk/qcom/clk-rcg.h b/drivers/clk/qcom/clk-rcg.h
index b209a2f..bffb625 100644
--- a/drivers/clk/qcom/clk-rcg.h
+++ b/drivers/clk/qcom/clk-rcg.h
@@ -161,4 +161,6 @@ struct clk_rcg2 {
extern const struct clk_ops clk_gfx3d_ops;
extern const struct clk_ops clk_rcg2_shared_ops;
+extern int qcom_cc_register_rcg_dfs(struct regmap *regmap,
+struct clk_rcg2 **rcgs, int num_clks);
#endif
diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c
index 52208d4..f8f1417 100644
--- a/drivers/clk/qcom/clk-rcg2.c
+++ b/drivers/clk/qcom/clk-rcg2.c
@@ -12,6 +12,7 @@
#include
#include
#include
+#include
#include
@@ -40,6 +41,14 @@
#define N_REG 0xc
#define D_REG 0x10
+/* Dynamic Frequency Scaling */
+#define MAX_PERF_LEVEL 8
+#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 +938,167 @@ 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 */
+static unsigned long clk_rcg2_calculate_freq(struct clk_hw *hw,
+ int level, struct freq_tbl *f)
+{
+ struct clk_rcg2 *rcg = to_clk_rcg2(hw);
+ struct clk_hw *p;
+ unsigned long prate = 0;
+ u32 val, mask, cfg, m_off, n_off, offset, mode;
+ int i, ret, num_parents;
+
+ offset = SE_PERF_DFSR(level);
+ ret = regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + offset, );
+ if (ret)
+ return ret;
+
+ mask = BIT(rcg->hid_width) - 1;
+ f->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;
+
+ num_parents = clk_hw_get_num_parents(hw);
+ for (i = 0; i < num_parents; i++) {
+ if (cfg == rcg->parent_map[i].cfg) {
+ f->src = rcg->parent_map[i].src;
+ p = clk_hw_get_parent_by_index(>clkr.hw, i);
+ prate = clk_hw_get_rate(p);
+ }
+ }
+
+ if (!mode)
+ goto done;
+
+ /* Calculate M & N values */
+ m_off = SE_PERF_M_DFSR(level);
+ n_off = SE_PERF_N_DFSR(level);
+
+ mask = BIT(rcg->mnd_width) - 1;
+ ret = regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + m_off, );
+ 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_off, );
+ 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;
+done:
+ return calc_rate(prate, f->m, f->n, mode, f->pre_div);
+}
+
+static int clk_rcg2_dfs_populate_freq_table(struct clk_rcg2 *rcg)
+{
+ struct freq_tbl *freq_tbl;
+ unsigned long calc_freq;
+ int i;
+
+ freq_tbl = kcalloc(MAX_PERF_LEVEL, sizeof(*freq_tbl),
+ GFP_KERNEL);
+ if (!freq_tbl)
+ return -ENOMEM;
+
+ for (i = 0; i < MAX_PERF_LEVEL; i++) {
+ calc_freq = clk_rcg2_calculate_freq(>clkr.hw,
+ i, _tbl[i]);
+ if (calc_freq < 0) {
+ kfree(freq_tbl);
+ return calc_freq;
+ }
+
+ freq_tbl[i].freq = calc_freq;
