From patchwork Wed Dec 19 21:38:54 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [3/6] drm: tegra: protect DC register access with mutex Date: Wed, 19 Dec 2012 11:38:54 -0000 From: Lucas Stach X-Patchwork-Id: 207522 Message-Id: <1355953137-31563-4-git-send-email-dev@lynxeye.de> To: dri-devel@lists.freedesktop.org Cc: Thierry Reding , "linux-tegra@vger.kernel.org" Window properties are programmed through a shared aperture and have to happen atomically. Also we do the read-update-write dance on some of the shared regs. To make sure that different functions don't stumble over each other protect the register access with a mutex. Signed-off-by: Lucas Stach --- We could probably make this a bit more fine grained, but this would add some complexity and I don't really see a win there for now. --- drivers/gpu/drm/tegra/dc.c | 13 +++++++++++++ drivers/gpu/drm/tegra/drm.h | 1 + 2 Dateien geändert, 14 Zeilen hinzugefügt(+) diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c index 54683e4..b256574 100644 --- a/drivers/gpu/drm/tegra/dc.c +++ b/drivers/gpu/drm/tegra/dc.c @@ -171,6 +171,8 @@ static int tegra_crtc_mode_set(struct drm_crtc *crtc, return err; } + mutex_lock(&dc->regs_mutex); + /* program display mode */ tegra_dc_set_timings(dc, mode); @@ -269,6 +271,8 @@ static int tegra_crtc_mode_set(struct drm_crtc *crtc, tegra_dc_writel(dc, 0xff00, DC_WIN_BLEND_NOKEY); tegra_dc_writel(dc, 0xff00, DC_WIN_BLEND_1WIN); + mutex_unlock(&dc->regs_mutex); + return 0; } @@ -287,6 +291,8 @@ static void tegra_crtc_prepare(struct drm_crtc *crtc) else syncpt = SYNCPT_VBLANK0; + mutex_lock(&dc->regs_mutex); + /* initialize display controller */ tegra_dc_writel(dc, 0x00000100, DC_CMD_GENERAL_INCR_SYNCPT_CNTRL); tegra_dc_writel(dc, 0x100 | syncpt, DC_CMD_CONT_SYNCPT_VSYNC); @@ -320,6 +326,8 @@ static void tegra_crtc_prepare(struct drm_crtc *crtc) value = VBLANK_INT | WIN_A_UF_INT | WIN_B_UF_INT | WIN_C_UF_INT; tegra_dc_writel(dc, value, DC_CMD_INT_ENABLE); + + mutex_unlock(&dc->regs_mutex); } static void tegra_crtc_commit(struct drm_crtc *crtc) @@ -330,6 +338,8 @@ static void tegra_crtc_commit(struct drm_crtc *crtc) update_mask = GENERAL_ACT_REQ | WIN_A_ACT_REQ; + mutex_lock(&dc->regs_mutex); + tegra_dc_writel(dc, update_mask << 8, DC_CMD_STATE_CONTROL); value = tegra_dc_readl(dc, DC_CMD_INT_ENABLE); @@ -341,6 +351,8 @@ static void tegra_crtc_commit(struct drm_crtc *crtc) tegra_dc_writel(dc, value, DC_CMD_INT_MASK); tegra_dc_writel(dc, update_mask, DC_CMD_STATE_CONTROL); + + mutex_unlock(&dc->regs_mutex); } static void tegra_crtc_load_lut(struct drm_crtc *crtc) @@ -747,6 +759,7 @@ static int tegra_dc_probe(struct platform_device *pdev) return -ENOMEM; INIT_LIST_HEAD(&dc->list); + mutex_init(&dc->regs_mutex); dc->dev = &pdev->dev; dc->clk = devm_clk_get(&pdev->dev, NULL); diff --git a/drivers/gpu/drm/tegra/drm.h b/drivers/gpu/drm/tegra/drm.h index 3a843a7..eae1f56 100644 --- a/drivers/gpu/drm/tegra/drm.h +++ b/drivers/gpu/drm/tegra/drm.h @@ -84,6 +84,7 @@ struct tegra_dc { struct clk *clk; + struct mutex regs_mutex; void __iomem *regs; int irq;