drm/msm/dpu: Integrate interconnect API in MDSS [Linux 5.3]

This Linux kernel change "drm/msm/dpu: Integrate interconnect API in MDSS" is included in the Linux 5.3 release. This change is authored by Jayant Shekhar <jshekhar [at] codeaurora.org> on Tue Jun 18 13:24:10 2019 -0700. The commit for this change in Linux stable tree is 20cad6c (patch).

drm/msm/dpu: Integrate interconnect API in MDSS

The interconnect framework is designed to provide a
standard kernel interface to control the settings of
the interconnects on a SoC.

The interconnect API uses a consumer/provider-based model,
where the providers are the interconnect buses and the
consumers could be various drivers.

MDSS is one of the interconnect consumers which uses the
interconnect APIs to get the path between endpoints and
set its bandwidth requirement for the given interconnected
path.

Changes in v2:
    - Remove error log and unnecessary check (Jordan Crouse)

Changes in v3:
    - Code clean involving variable name change, removal
      of extra paranthesis and variables (Matthias Kaehlcke)

Changes in v4:
    - Add comments, spacings, tabs, proper port name
      and icc macro (Georgi Djakov)

Changes in v5:
    - Commit text and parenthesis alignment (Georgi Djakov)

Changes in v6:
    - Change to new icc_set API's (Doug Anderson)

Changes in v7:
    - Fixed a typo

Changes in v8:
    - Handle the of_icc_get() returning NULL case.  In practice
      icc_set_bw() will gracefully handle the case of a NULL path,
      but it's probably best for clarity to keep num_paths=0 in
      this case.

Signed-off-by: Sravanthi Kollukuduru <skolluku@codeaurora.org>
Signed-off-by: Jayant Shekhar <jshekhar@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>
Acked-by: Georgi Djakov <georgi.djakov@linaro.org>
Reviewed-by: Sean Paul <sean@poorly.run>

There are 49 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c | 49 +++++++++++++++++++++++++++++---
 1 file changed, 45 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c
index 7316b4a..b1d0437 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c
@@ -4,11 +4,15 @@
  */

 #include "dpu_kms.h"
+#include <linux/interconnect.h>

 #define to_dpu_mdss(x) container_of(x, struct dpu_mdss, base)

 #define HW_INTR_STATUS         0x0010

+/* Max BW defined in KBps */
+#define MAX_BW             6800000
+
 struct dpu_irq_controller {
    unsigned long enabled_mask;
    struct irq_domain *domain;
@@ -21,8 +25,30 @@ struct dpu_mdss {
    u32 hwversion;
    struct dss_module_power mp;
    struct dpu_irq_controller irq_controller;
+   struct icc_path *path[2];
+   u32 num_paths;
 };

+static int dpu_mdss_parse_data_bus_icc_path(struct drm_device *dev,
+                       struct dpu_mdss *dpu_mdss)
+{
+   struct icc_path *path0 = of_icc_get(dev->dev, "mdp0-mem");
+   struct icc_path *path1 = of_icc_get(dev->dev, "mdp1-mem");
+
+   if (IS_ERR_OR_NULL(path0))
+       return PTR_ERR_OR_ZERO(path0);
+
+   dpu_mdss->path[0] = path0;
+   dpu_mdss->num_paths = 1;
+
+   if (!IS_ERR_OR_NULL(path1)) {
+       dpu_mdss->path[1] = path1;
+       dpu_mdss->num_paths++;
+   }
+
+   return 0;
+}
+
 static void dpu_mdss_irq(struct irq_desc *desc)
 {
    struct dpu_mdss *dpu_mdss = irq_desc_get_handler_data(desc);
@@ -134,7 +160,11 @@ static int dpu_mdss_enable(struct msm_mdss *mdss)
 {
    struct dpu_mdss *dpu_mdss = to_dpu_mdss(mdss);
    struct dss_module_power *mp = &dpu_mdss->mp;
-   int ret;
+   int ret, i;
+   u64 avg_bw = dpu_mdss->num_paths ? MAX_BW / dpu_mdss->num_paths : 0;
+
+   for (i = 0; i < dpu_mdss->num_paths; i++)
+       icc_set_bw(dpu_mdss->path[i], avg_bw, kBps_to_icc(MAX_BW));

    ret = msm_dss_enable_clk(mp->clk_config, mp->num_clk, true);
    if (ret)
@@ -147,12 +177,15 @@ static int dpu_mdss_disable(struct msm_mdss *mdss)
 {
    struct dpu_mdss *dpu_mdss = to_dpu_mdss(mdss);
    struct dss_module_power *mp = &dpu_mdss->mp;
-   int ret;
+   int ret, i;

    ret = msm_dss_enable_clk(mp->clk_config, mp->num_clk, false);
    if (ret)
        DPU_ERROR("clock disable failed, ret:%d\n", ret);

+   for (i = 0; i < dpu_mdss->num_paths; i++)
+       icc_set_bw(dpu_mdss->path[i], 0, 0);
+
    return ret;
 }

@@ -163,6 +196,7 @@ static void dpu_mdss_destroy(struct drm_device *dev)
    struct dpu_mdss *dpu_mdss = to_dpu_mdss(priv->mdss);
    struct dss_module_power *mp = &dpu_mdss->mp;
    int irq;
+   int i;

    pm_runtime_suspend(dev->dev);
    pm_runtime_disable(dev->dev);
@@ -172,6 +206,9 @@ static void dpu_mdss_destroy(struct drm_device *dev)
    msm_dss_put_clk(mp->clk_config, mp->num_clk);
    devm_kfree(&pdev->dev, mp->clk_config);

+   for (i = 0; i < dpu_mdss->num_paths; i++)
+       icc_put(dpu_mdss->path[i]);
+
    if (dpu_mdss->mmio)
        devm_iounmap(&pdev->dev, dpu_mdss->mmio);
    dpu_mdss->mmio = NULL;
@@ -211,6 +248,10 @@ int dpu_mdss_init(struct drm_device *dev)
    }
    dpu_mdss->mmio_len = resource_size(res);

+   ret = dpu_mdss_parse_data_bus_icc_path(dev, dpu_mdss);
+   if (ret)
+       return ret;
+
    mp = &dpu_mdss->mp;
    ret = msm_dss_parse_clock(pdev, mp);
    if (ret) {
@@ -232,14 +273,14 @@ int dpu_mdss_init(struct drm_device *dev)
    irq_set_chained_handler_and_data(irq, dpu_mdss_irq,
                     dpu_mdss);

+   priv->mdss = &dpu_mdss->base;
+
    pm_runtime_enable(dev->dev);

    pm_runtime_get_sync(dev->dev);
    dpu_mdss->hwversion = readl_relaxed(dpu_mdss->mmio);
    pm_runtime_put_sync(dev->dev);

-   priv->mdss = &dpu_mdss->base;
-
    return ret;

 irq_error:

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