drm/tegra: dsi: Refactor in preparation for command mode

For command mode panels, the DSI controller needs to be enabled and
configured so that panel drivers can send commands prior to the video
stream being enabled.

Move code from the monolithic output enable/disable functions into
smaller, reusable units to allow more fine-grained control over the
controller state.
Signed-off-by: NThierry Reding <treding@nvidia.com>

drivers/gpu/drm/tegra/dsi.c

@@ -426,20 +426,24 @@ static int tegra_dsi_get_format(enum mipi_dsi_pixel_format format,
 	return 0;
 }
 
-static int tegra_output_dsi_enable(struct tegra_output *output)
+static void tegra_dsi_enable(struct tegra_dsi *dsi)
+{
+	u32 value;
+
+	value = tegra_dsi_readl(dsi, DSI_POWER_CONTROL);
+	value |= DSI_POWER_CONTROL_ENABLE;
+	tegra_dsi_writel(dsi, value, DSI_POWER_CONTROL);
+}
+
+static int tegra_dsi_configure(struct tegra_dsi *dsi, unsigned int pipe,
+			       const struct drm_display_mode *mode)
 {
-	struct tegra_dc *dc = to_tegra_dc(output->encoder.crtc);
-	struct drm_display_mode *mode = &dc->base.mode;
 	unsigned int hact, hsw, hbp, hfp, i, mul, div;
-	struct tegra_dsi *dsi = to_dsi(output);
 	enum tegra_dsi_format format;
-	unsigned long value;
 	const u32 *pkt_seq;
+	u32 value;
 	int err;
 
-	if (dsi->enabled)
-		return 0;
-
 	if (dsi->flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE) {
 		DRM_DEBUG_KMS("Non-burst video mode with sync pulses\n");
 		pkt_seq = pkt_seq_video_non_burst_sync_pulses;
@@ -458,18 +462,19 @@ static int tegra_output_dsi_enable(struct tegra_output *output)
 
 	value = DSI_CONTROL_CHANNEL(0) | DSI_CONTROL_FORMAT(format) |
 		DSI_CONTROL_LANES(dsi->lanes - 1) |
-		DSI_CONTROL_SOURCE(dc->pipe);
+		DSI_CONTROL_SOURCE(pipe);
 	tegra_dsi_writel(dsi, value, DSI_CONTROL);
 
 	tegra_dsi_writel(dsi, dsi->video_fifo_depth, DSI_MAX_THRESHOLD);
 
-	value = DSI_HOST_CONTROL_HS | DSI_HOST_CONTROL_CS |
-		DSI_HOST_CONTROL_ECC;
+	value = DSI_HOST_CONTROL_HS;
 	tegra_dsi_writel(dsi, value, DSI_HOST_CONTROL);
 
 	value = tegra_dsi_readl(dsi, DSI_CONTROL);
+
 	if (dsi->flags & MIPI_DSI_CLOCK_NON_CONTINUOUS)
 		value |= DSI_CONTROL_HS_CLK_CTRL;
+
 	value &= ~DSI_CONTROL_TX_TRIG(3);
 	value &= ~DSI_CONTROL_DCS_ENABLE;
 	value |= DSI_CONTROL_VIDEO_ENABLE;
@@ -503,9 +508,27 @@ static int tegra_output_dsi_enable(struct tegra_output *output)
 	tegra_dsi_writel(dsi, hfp, DSI_PKT_LEN_4_5);
 	tegra_dsi_writel(dsi, 0x0f0f << 16, DSI_PKT_LEN_6_7);
 
-	/* set SOL delay */
+	/* set SOL delay (for non-burst mode only) */
 	tegra_dsi_writel(dsi, 8 * mul / div, DSI_SOL_DELAY);
 
+	return 0;
+}
+
+static int tegra_output_dsi_enable(struct tegra_output *output)
+{
+	struct tegra_dc *dc = to_tegra_dc(output->encoder.crtc);
+	const struct drm_display_mode *mode = &dc->base.mode;
+	struct tegra_dsi *dsi = to_dsi(output);
+	u32 value;
+	int err;
+
+	if (dsi->enabled)
+		return 0;
+
+	err = tegra_dsi_configure(dsi, dc->pipe, mode);
+	if (err < 0)
+		return err;
+
 	/* enable display controller */
 	value = tegra_dc_readl(dc, DC_DISP_DISP_WIN_OPTIONS);
 	value |= DSI_ENABLE;
@@ -525,28 +548,61 @@ static int tegra_output_dsi_enable(struct tegra_output *output)
 	tegra_dc_writel(dc, GENERAL_ACT_REQ, DC_CMD_STATE_CONTROL);
 
 	/* enable DSI controller */
-	value = tegra_dsi_readl(dsi, DSI_POWER_CONTROL);
-	value |= DSI_POWER_CONTROL_ENABLE;
-	tegra_dsi_writel(dsi, value, DSI_POWER_CONTROL);
+	tegra_dsi_enable(dsi);
 
 	dsi->enabled = true;
 
 	return 0;
 }
 
+static int tegra_dsi_wait_idle(struct tegra_dsi *dsi, unsigned long timeout)
+{
+	u32 value;
+
+	timeout = jiffies + msecs_to_jiffies(timeout);
+
+	while (time_before(jiffies, timeout)) {
+		value = tegra_dsi_readl(dsi, DSI_STATUS);
+		if (value & DSI_STATUS_IDLE)
+			return 0;
+
+		usleep_range(1000, 2000);
+	}
+
+	return -ETIMEDOUT;
+}
+
+static void tegra_dsi_video_disable(struct tegra_dsi *dsi)
+{
+	u32 value;
+
+	value = tegra_dsi_readl(dsi, DSI_CONTROL);
+	value &= ~DSI_CONTROL_VIDEO_ENABLE;
+	tegra_dsi_writel(dsi, value, DSI_CONTROL);
+}
+
+static void tegra_dsi_disable(struct tegra_dsi *dsi)
+{
+	u32 value;
+
+	value = tegra_dsi_readl(dsi, DSI_POWER_CONTROL);
+	value &= ~DSI_POWER_CONTROL_ENABLE;
+	tegra_dsi_writel(dsi, value, DSI_POWER_CONTROL);
+
+	usleep_range(5000, 10000);
+}
+
 static int tegra_output_dsi_disable(struct tegra_output *output)
 {
 	struct tegra_dc *dc = to_tegra_dc(output->encoder.crtc);
 	struct tegra_dsi *dsi = to_dsi(output);
 	unsigned long value;
+	int err;
 
 	if (!dsi->enabled)
 		return 0;
 
-	/* disable DSI controller */
-	value = tegra_dsi_readl(dsi, DSI_POWER_CONTROL);
-	value &= ~DSI_POWER_CONTROL_ENABLE;
-	tegra_dsi_writel(dsi, value, DSI_POWER_CONTROL);
+	tegra_dsi_video_disable(dsi);
 
 	/*
 	 * The following accesses registers of the display controller, so make
@@ -570,6 +626,12 @@ static int tegra_output_dsi_disable(struct tegra_output *output)
 		tegra_dc_writel(dc, GENERAL_ACT_REQ, DC_CMD_STATE_CONTROL);
 	}
 
+	err = tegra_dsi_wait_idle(dsi, 100);
+	if (err < 0)
+		dev_dbg(dsi->dev, "failed to idle DSI: %d\n", err);
+
+	tegra_dsi_disable(dsi);
+
 	dsi->enabled = false;
 
 	return 0;