drm/msm/dpu: add icc voting in dpu_mdss_init [Linux 5.3]

This Linux kernel change "drm/msm/dpu: add icc voting in dpu_mdss_init" is included in the Linux 5.3 release. This change is authored by Abhinav Kumar <abhinavk [at] codeaurora.org> on Tue Jun 18 13:24:12 2019 -0700. The commit for this change in Linux stable tree is 217a6dd (patch).

drm/msm/dpu: add icc voting in dpu_mdss_init

dpu_mdss_destroy() can get called not just from
msm_drm_uninit() but also from msm_drm_bind() in case
of any failures.

dpu_mdss_destroy() removes the icc voting by calling
icc_put. This could accidentally remove the voting
done by pm_runtime_enable.

To make the voting balanced add a minimum vote in
dpu_mdss_init() to avoid any unclocked access.

This change depends on the following patch which
introduces interconnect binding to MDSS driver:

https://patchwork.codeaurora.org/patch/708155/

Signed-off-by: Abhinav Kumar <abhinavk@codeaurora.org>
Reviewed-by: Sean Paul <sean@poorly.run>
Signed-off-by: Rob Clark <robdclark@chromium.org>

There are 18 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 | 18 ++++++++++++++----
 1 file changed, 14 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 b1d0437..986915b 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c
@@ -49,6 +49,16 @@ static int dpu_mdss_parse_data_bus_icc_path(struct drm_device *dev,
    return 0;
 }

+static void dpu_mdss_icc_request_bw(struct msm_mdss *mdss)
+{
+   struct dpu_mdss *dpu_mdss = to_dpu_mdss(mdss);
+   int 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));
+}
+
 static void dpu_mdss_irq(struct irq_desc *desc)
 {
    struct dpu_mdss *dpu_mdss = irq_desc_get_handler_data(desc);
@@ -160,11 +170,9 @@ 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, i;
-   u64 avg_bw = dpu_mdss->num_paths ? MAX_BW / dpu_mdss->num_paths : 0;
+   int ret;

-   for (i = 0; i < dpu_mdss->num_paths; i++)
-       icc_set_bw(dpu_mdss->path[i], avg_bw, kBps_to_icc(MAX_BW));
+   dpu_mdss_icc_request_bw(mdss);

    ret = msm_dss_enable_clk(mp->clk_config, mp->num_clk, true);
    if (ret)
@@ -277,6 +285,8 @@ int dpu_mdss_init(struct drm_device *dev)

    pm_runtime_enable(dev->dev);

+   dpu_mdss_icc_request_bw(priv->mdss);
+
    pm_runtime_get_sync(dev->dev);
    dpu_mdss->hwversion = readl_relaxed(dpu_mdss->mmio);
    pm_runtime_put_sync(dev->dev);

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