[PATCH v2] drm: renesas: rz-du: mipi_dsi: Fix return path on error

[Chris Brandt <chris.brandt@renesas.com>]

In case of error, we should unwind correctly.
Switching to using dmam_ instead of dma_ and moving the code earlier
fixes the issue.

Fixes: 6f392f371650 ("drm: renesas: rz-du: Implement MIPI DSI host transfers")
Suggested-by: Pavel Machek <pavel@nabladev.com>
Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Acked-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>

---
V1->V2:
 - Need to take into account mipi_dsi_host_register was already called (Geert)
 - Switch to using dmam_alloc_coherent to automate unwinding (Chris)
 - Added Acked-by (Hugo)
---
 drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
index 29f2b7d24fe5..b908e702b607 100644
--- a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
+++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
@@ -1442,6 +1442,11 @@ static int rzg2l_mipi_dsi_probe(struct platform_device *pdev)
 		return dev_err_probe(dsi->dev, PTR_ERR(dsi->prstc),
 				     "failed to get prst\n");

+	dsi->dcs_buf_virt = dmam_alloc_coherent(dsi->dev, RZG2L_DCS_BUF_SIZE,
+						&dsi->dcs_buf_phys, GFP_KERNEL);
+	if (!dsi->dcs_buf_virt)
+		return -ENOMEM;
+
 	platform_set_drvdata(pdev, dsi);

 	pm_runtime_enable(dsi->dev);
@@ -1474,11 +1479,6 @@ static int rzg2l_mipi_dsi_probe(struct platform_device *pdev)
 	if (ret < 0)
 		goto err_pm_disable;

-	dsi->dcs_buf_virt = dma_alloc_coherent(dsi->host.dev, RZG2L_DCS_BUF_SIZE,
-					       &dsi->dcs_buf_phys, GFP_KERNEL);
-	if (!dsi->dcs_buf_virt)
-		return -ENOMEM;
-
 	return 0;

 err_phy:
@@ -1493,8 +1493,6 @@ static void rzg2l_mipi_dsi_remove(struct platform_device *pdev)
 {
 	struct rzg2l_mipi_dsi *dsi = platform_get_drvdata(pdev);

-	dma_free_coherent(dsi->host.dev, RZG2L_DCS_BUF_SIZE, dsi->dcs_buf_virt,
-			  dsi->dcs_buf_phys);
 	mipi_dsi_host_unregister(&dsi->host);
 	pm_runtime_disable(&pdev->dev);
 }
--
2.52.0