drm/msm/dsi: free TX buffer in unbind

If the drm/msm init code gets an error during output modeset
initialisation, the kernel will report an error regarding DRM memory
manager not being clean during shutdown. This is because
msm_dsi_modeset_init() allocates a piece of GEM memory for the TX
buffer, but destruction of the buffer happens only at
msm_dsi_host_destroy(), which is called during DSI driver's remove()
time, much later than the DRM MM shutdown.

To solve this issue, move the TX buffer destruction to dsi_unbind(), so
that the buffer is destructed at the correct time. Note, we also have to
store a reference to the address space, because priv->kms->aspace is
cleared before components are unbound.
Reported-by: Bjorn Andersson <andersson@kernel.org>
Fixes: 8f59ee9a ("drm/msm/dsi: Adjust probe order")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/562238/Signed-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/dsi/dsi.c

@@ -131,6 +131,7 @@ static void dsi_unbind(struct device *dev, struct device *master,
 	struct msm_drm_private *priv = dev_get_drvdata(master);
 	struct msm_dsi *msm_dsi = dev_get_drvdata(dev);
 
+	msm_dsi_tx_buf_free(msm_dsi->host);
 	priv->dsi[msm_dsi->id] = NULL;
 }
 

drivers/gpu/drm/msm/dsi/dsi.h

@@ -124,6 +124,7 @@ int dsi_tx_buf_alloc_v2(struct msm_dsi_host *msm_host, int size);
 void *dsi_tx_buf_get_6g(struct msm_dsi_host *msm_host);
 void *dsi_tx_buf_get_v2(struct msm_dsi_host *msm_host);
 void dsi_tx_buf_put_6g(struct msm_dsi_host *msm_host);
+void msm_dsi_tx_buf_free(struct mipi_dsi_host *mipi_host);
 int dsi_dma_base_get_6g(struct msm_dsi_host *msm_host, uint64_t *iova);
 int dsi_dma_base_get_v2(struct msm_dsi_host *msm_host, uint64_t *iova);
 int dsi_clk_init_v2(struct msm_dsi_host *msm_host);

drivers/gpu/drm/msm/dsi/dsi_host.c

@@ -147,6 +147,7 @@ struct msm_dsi_host {
 
 	/* DSI 6G TX buffer*/
 	struct drm_gem_object *tx_gem_obj;
+	struct msm_gem_address_space *aspace;
 
 	/* DSI v2 TX buffer */
 	void *tx_buf;
@@ -1134,8 +1135,10 @@ int dsi_tx_buf_alloc_6g(struct msm_dsi_host *msm_host, int size)
 	uint64_t iova;
 	u8 *data;
 
+	msm_host->aspace = msm_gem_address_space_get(priv->kms->aspace);
+
 	data = msm_gem_kernel_new(dev, size, MSM_BO_WC,
-					priv->kms->aspace,
+					msm_host->aspace,
 					&msm_host->tx_gem_obj, &iova);
 
 	if (IS_ERR(data)) {
@@ -1164,10 +1167,10 @@ int dsi_tx_buf_alloc_v2(struct msm_dsi_host *msm_host, int size)
 	return 0;
 }
 
-static void dsi_tx_buf_free(struct msm_dsi_host *msm_host)
+void msm_dsi_tx_buf_free(struct mipi_dsi_host *host)
 {
+	struct msm_dsi_host *msm_host = to_msm_dsi_host(host);
 	struct drm_device *dev = msm_host->dev;
-	struct msm_drm_private *priv;
 
 	/*
 	 * This is possible if we're tearing down before we've had a chance to
@@ -1178,10 +1181,11 @@ static void dsi_tx_buf_free(struct msm_dsi_host *msm_host)
 	if (!dev)
 		return;
 
-	priv = dev->dev_private;
 	if (msm_host->tx_gem_obj) {
-		msm_gem_kernel_put(msm_host->tx_gem_obj, priv->kms->aspace);
+		msm_gem_kernel_put(msm_host->tx_gem_obj, msm_host->aspace);
+		msm_gem_address_space_put(msm_host->aspace);
 		msm_host->tx_gem_obj = NULL;
+		msm_host->aspace = NULL;
 	}
 
 	if (msm_host->tx_buf)
@@ -1967,7 +1971,6 @@ void msm_dsi_host_destroy(struct mipi_dsi_host *host)
 	struct msm_dsi_host *msm_host = to_msm_dsi_host(host);
 
 	DBG("");
-	dsi_tx_buf_free(msm_host);
 	if (msm_host->workqueue) {
 		destroy_workqueue(msm_host->workqueue);
 		msm_host->workqueue = NULL;