Re: [PATCH v1] clk: qcom: clk-rpmh: Add IPA clock support

From: Stephen Boyd
Date: Wed Jan 09 2019 - 14:28:35 EST


Quoting David Dai (2018-12-13 18:35:04)
> The current clk-rpmh driver only supports on and off RPMh clock resources,
> let's extend the current driver by add support for clocks that are managed
> by a different type of RPMh resource known as Bus Clock Manager(BCM).
> The BCM is a configurable shared resource aggregator that scales performance
> based on a preset of frequency points. The Qualcomm IP Accelerator (IPA) clock
> is an example of a resource that is managed by the BCM and this a requirement
> from the IPA driver in order to scale its core clock.

Please use this commit text instead:


The clk-rpmh driver only supports on and off RPMh clock resources. Let's
extend the driver by add support for clocks that are managed by a
different type of RPMh resource known as Bus Clock Manager(BCM). The BCM
is a configurable shared resource aggregator that scales performance
based on a set of frequency points. The Qualcomm IP Accelerator (IPA)
clock is an example of a resource that is managed by the BCM and this a
requirement from the IPA driver in order to scale its core clock.

>
> Signed-off-by: David Dai <daidavid1@xxxxxxxxxxxxxx>
> ---
> drivers/clk/qcom/clk-rpmh.c | 141 ++++++++++++++++++++++++++++++++++
> include/dt-bindings/clock/qcom,rpmh.h | 1 +
> 2 files changed, 142 insertions(+)
>
> diff --git a/drivers/clk/qcom/clk-rpmh.c b/drivers/clk/qcom/clk-rpmh.c
> index 9f4fc77..ee78c4b 100644
> --- a/drivers/clk/qcom/clk-rpmh.c
> +++ b/drivers/clk/qcom/clk-rpmh.c
> @@ -18,6 +18,31 @@
> #define CLK_RPMH_ARC_EN_OFFSET 0
> #define CLK_RPMH_VRM_EN_OFFSET 4
>
> +#define BCM_TCS_CMD_COMMIT_MASK 0x40000000
> +#define BCM_TCS_CMD_VALID_SHIFT 29
> +#define BCM_TCS_CMD_VOTE_MASK 0x3fff
> +#define BCM_TCS_CMD_VOTE_SHIFT 0
> +
> +#define BCM_TCS_CMD(valid, vote) \
> + (BCM_TCS_CMD_COMMIT_MASK | \
> + ((valid) << BCM_TCS_CMD_VALID_SHIFT) | \
> + ((cpu_to_le32(vote) & \

Why?

> + BCM_TCS_CMD_VOTE_MASK) << BCM_TCS_CMD_VOTE_SHIFT))
> +
> +/**
> + * struct bcm_db - Auxiliary data pertaining to each Bus Clock Manager(BCM)
> + * @unit: divisor used to convert Hz value to an RPMh msg
> + * @width: multiplier used to convert Hz value to an RPMh msg
> + * @vcd: virtual clock domain that this bcm belongs to
> + * @reserved: reserved to pad the struct
> + */
> +struct bcm_db {
> + __le32 unit;
> + __le16 width;
> + u8 vcd;
> + u8 reserved;
> +};
> +
> /**
> * struct clk_rpmh - individual rpmh clock data structure
> * @hw: handle between common and hardware-specific interfaces
> @@ -29,6 +54,7 @@
> * @aggr_state: rpmh clock aggregated state
> * @last_sent_aggr_state: rpmh clock last aggr state sent to RPMh
> * @valid_state_mask: mask to determine the state of the rpmh clock
> + * @aux_data: data specific to the bcm rpmh resource

But there isn't aux_data. Is this supposed to be unit? And what is unit
going to be? 1000?

> * @dev: device to which it is attached
> * @peer: pointer to the clock rpmh sibling
> */
> @@ -42,6 +68,7 @@ struct clk_rpmh {
> u32 aggr_state;
> u32 last_sent_aggr_state;
> u32 valid_state_mask;
> + u32 unit;
> struct device *dev;
> struct clk_rpmh *peer;
> };
> @@ -210,6 +248,91 @@ static unsigned long clk_rpmh_recalc_rate(struct clk_hw *hw,
> .recalc_rate = clk_rpmh_recalc_rate,
> };
>
> +static int clk_rpmh_bcm_send_cmd(struct clk_rpmh *c, bool enable)
> +{
> + struct tcs_cmd cmd = { 0 };
> + u32 cmd_state;
> + int ret;
> +
> + mutex_lock(&rpmh_clk_lock);
> +
> + cmd_state = enable ? (c->aggr_state ? c->aggr_state : 1) : 0;

Make this into an if statement instead of double ternary?

cmd_state = 0;
if (enable) {
cmd_state = 1;
if (c->aggr_state)
cmd_state = c->aggr_state;

}

> +
> + if (c->last_sent_aggr_state == cmd_state)
> + return 0;

We just returned with a mutex held. Oops!

> +
> + cmd.addr = c->res_addr;
> + cmd.data = BCM_TCS_CMD(enable, cmd_state);
> +
> + ret = rpmh_write_async(c->dev, RPMH_ACTIVE_ONLY_STATE, &cmd, 1);
> + if (ret) {
> + dev_err(c->dev, "set active state of %s failed: (%d)\n",
> + c->res_name, ret);
> + return ret;

Again!

> + }
> +
> + c->last_sent_aggr_state = cmd_state;
> +
> + mutex_unlock(&rpmh_clk_lock);
> +
> + return 0;
> +}
> +
> +static int clk_rpmh_bcm_prepare(struct clk_hw *hw)
> +{
> + struct clk_rpmh *c = to_clk_rpmh(hw);
> + int ret;
> +
> + ret = clk_rpmh_bcm_send_cmd(c, true);
> +
> + return ret;

Just write return clk_rpmh_bcm_send_cmd(...)

> +};
> +
> +static void clk_rpmh_bcm_unprepare(struct clk_hw *hw)
> +{
> + struct clk_rpmh *c = to_clk_rpmh(hw);
> +
> + clk_rpmh_bcm_send_cmd(c, false);
> +};
> +
> +static int clk_rpmh_bcm_set_rate(struct clk_hw *hw, unsigned long rate,
> + unsigned long parent_rate)
> +{
> + struct clk_rpmh *c = to_clk_rpmh(hw);
> +
> + c->aggr_state = rate / c->unit;
> + /*
> + * Since any non-zero value sent to hw would result in enabling the
> + * clock, only send the value if the clock has already been prepared.
> + */
> + if (clk_hw_is_prepared(hw))

This is sad, but OK.

> + clk_rpmh_bcm_send_cmd(c, true);
> +
> + return 0;
> +};
> +
[...]
> @@ -217,6 +340,7 @@ static unsigned long clk_rpmh_recalc_rate(struct clk_hw *hw,
> DEFINE_CLK_RPMH_VRM(sdm845, rf_clk1, rf_clk1_ao, "rfclka1", 1);
> DEFINE_CLK_RPMH_VRM(sdm845, rf_clk2, rf_clk2_ao, "rfclka2", 1);
> DEFINE_CLK_RPMH_VRM(sdm845, rf_clk3, rf_clk3_ao, "rfclka3", 1);
> +DEFINE_CLK_RPMH_BCM(sdm845, ipa, "IP0");

It's really IP0?! What was wrong with IPA?

>
> static struct clk_hw *sdm845_rpmh_clocks[] = {
> [RPMH_CXO_CLK] = &sdm845_bi_tcxo.hw,
> @@ -275,6 +402,20 @@ static int clk_rpmh_probe(struct platform_device *pdev)
> rpmh_clk->res_name);
> return -ENODEV;
> }
> +
> + data = cmd_db_read_aux_data(rpmh_clk->res_name, &aux_data_len);
> + if (IS_ERR(data)) {
> + ret = PTR_ERR(data);
> + dev_err(&pdev->dev,
> + "error reading RPMh aux data for %s (%d)\n",
> + rpmh_clk->res_name, ret);
> + return ret;

Weird indent here.