Re: [PATCH V4 3/9] soc: qcom: geni: Support for ICC voting

Akash Asthana <akashast@xxxxxxxxxxxxxx> · Tue, 28 Apr 2020 15:18:13 +0530

Hi Matthias,

On 4/16/2020 5:06 AM, Matthias Kaehlcke wrote:
Hi Akash,

On Wed, Apr 15, 2020 at 03:53:12PM +0530, Akash Asthana wrote:
Add necessary macros and structure variables to support ICC BW
voting from individual SE drivers.

Signed-off-by: Akash Asthana <akashast@xxxxxxxxxxxxxx>
---
Changes in V2:
  - As per Bjorn's comment dropped enums for ICC paths, given the three
    paths individual members

Changes in V3:
  - Add geni_icc_get, geni_icc_vote_on and geni_icc_vote_off as helper API.
  - Add geni_icc_path structure in common header

Changes in V4:
  - As per Bjorn's comment print error message in geni_icc_get if return
    value is not -EPROBE_DEFER.
  - As per Bjorn's comment remove NULL on path before calling icc_set_bw
    API.
  - As per Bjorn's comment drop __func__ print.
  - As per Matthias's comment, make ICC path a array instead of individual
    member entry in geni_se struct.

Note: I have ignored below check patch suggestion because it was throwing
       compilation error as 'icc_ddr' is not compile time comstant.

WARNING: char * array declaration might be better as static const
  - FILE: drivers/soc/qcom/qcom-geni-se.c:726:
  - const char *icc_names[] = {"qup-core", "qup-config", icc_ddr};


  drivers/soc/qcom/qcom-geni-se.c | 61 +++++++++++++++++++++++++++++++++++++++++
  include/linux/qcom-geni-se.h    | 31 +++++++++++++++++++++
  2 files changed, 92 insertions(+)

diff --git a/drivers/soc/qcom/qcom-geni-se.c b/drivers/soc/qcom/qcom-geni-se.c
index 7d622ea..1527bc4 100644
--- a/drivers/soc/qcom/qcom-geni-se.c
+++ b/drivers/soc/qcom/qcom-geni-se.c
@@ -720,6 +720,67 @@ void geni_se_rx_dma_unprep(struct geni_se *se, dma_addr_t iova, size_t len)
  }
  EXPORT_SYMBOL(geni_se_rx_dma_unprep);
  
+int geni_icc_get(struct geni_se *se, const char *icc_ddr)
+{
+	int i, icc_err;
+	const char *icc_names[] = {"qup-core", "qup-config", icc_ddr};
+
+	for (i = 0; i < ARRAY_SIZE(se->icc_paths); i++) {
+		if (!icc_names[i])
+			continue;
+
+		se->icc_paths[i].path = devm_of_icc_get(se->dev, icc_names[i]);
+		if (IS_ERR(se->icc_paths[i].path))
+			goto icc_get_failure;
+	}
+
+	return 0;
+
+icc_get_failure:
+	icc_err = PTR_ERR(se->icc_paths[i].path);
+	if (icc_err != -EPROBE_DEFER)
+		dev_err_ratelimited(se->dev, "Failed to get path:%d, ret:%d\n",
Better be explicit that it's an ICC path and log icc_names[i] instead of i.

+					i, icc_err);
+	return icc_err;
+
+}
+EXPORT_SYMBOL(geni_icc_get);
+
+int geni_icc_vote_on(struct geni_se *se)
+{
+	int i, ret;
+
+	for (i = 0; i < ARRAY_SIZE(se->icc_paths); i++) {
+		ret = icc_set_bw(se->icc_paths[i].path,
+			se->icc_paths[i].avg_bw, se->icc_paths[i].peak_bw);
I'll leave it to others to decide whether it's ok to leave the
implementation of the icc_enable/disable() APIs suggested on
https://patchwork.kernel.org/patch/11467511/#23269555 for later.

+		if (ret) {
+			dev_err_ratelimited(se->dev, "ICC BW voting failed on path:%d, ret:%d\n",
+					i, ret);
Instead of logging the index, which isn't very expressive, you could have
a static string array of the path names ({"core", "config", "ddr"} or
similar) that is used when logging errors in _vote_on/off().

+			return ret;
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(geni_icc_vote_on);
+
+int geni_icc_vote_off(struct geni_se *se)
+{
+	int i, ret;
+
+	for (i = 0; i < ARRAY_SIZE(se->icc_paths); i++) {
+		ret = icc_set_bw(se->icc_paths[i].path, 0, 0);
+		if (ret) {
+			dev_err_ratelimited(se->dev, "ICC BW remove failed on path:%d, ret:%d\n",
+					i, ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(geni_icc_vote_off);
+
  static int geni_se_probe(struct platform_device *pdev)
  {
  	struct device *dev = &pdev->dev;
diff --git a/include/linux/qcom-geni-se.h b/include/linux/qcom-geni-se.h
index dd46494..b5b9316 100644
--- a/include/linux/qcom-geni-se.h
+++ b/include/linux/qcom-geni-se.h
@@ -6,6 +6,8 @@
  #ifndef _LINUX_QCOM_GENI_SE
  #define _LINUX_QCOM_GENI_SE
  
+#include <linux/interconnect.h>
+
  /* Transfer mode supported by GENI Serial Engines */
  enum geni_se_xfer_mode {
  	GENI_SE_INVALID,
@@ -25,6 +27,12 @@ enum geni_se_protocol_type {
  struct geni_wrapper;
  struct clk;
  
+struct geni_icc_path {
+	struct icc_path *path;
+	unsigned int avg_bw;
+	unsigned int peak_bw;
+};
+
  /**
   * struct geni_se - GENI Serial Engine
   * @base:		Base Address of the Serial Engine's register block
@@ -33,6 +41,7 @@ struct clk;
   * @clk:		Handle to the core serial engine clock
   * @num_clk_levels:	Number of valid clock levels in clk_perf_tbl
   * @clk_perf_tbl:	Table of clock frequency input to serial engine clock
+ * @icc_paths:		Array of ICC paths for SE
   */
  struct geni_se {
  	void __iomem *base;
@@ -41,6 +50,7 @@ struct geni_se {
  	struct clk *clk;
  	unsigned int num_clk_levels;
  	unsigned long *clk_perf_tbl;
+	struct geni_icc_path icc_paths[3];
You also need enums for the paths, otherwise you end up with code like
this, which isn't really self-explanatory:

   gi2c->se.icc_paths[0].avg_bw = GENI_DEFAULT_BW;
   gi2c->se.icc_paths[1].avg_bw = GENI_DEFAULT_BW;
   gi2c->se.icc_paths[2].avg_bw = Bps_to_icc(gi2c->clk_freq_out);

   (from "[V4,5/9] i2c: i2c-qcom-geni: Add interconnect support")

I know Bjorn asked in v1 to remove the enums you had, however it was
a slightly different context. If we are sticking to use an array of
'struct geni_icc_path' (which reduces redundant code) the enums are
'needed'.

Ok

Regards,

Akash

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