[10/11] drm/tinydrm: Use drm_dev_enter/exit()

Commit Message

Noralf Trønnes Jan. 20, 2019, 11:43 a.m. UTC

This protects device resources from use after device removal.

There are 3 ways for driver-device unbinding to happen:
- The driver module is unloaded causing the driver to be unregistered.
  This can't happen as long as there are open file handles because a
  reference is taken on the module.
- The device is removed (Device Tree overlay unloading).
  This can happen at any time.
- The driver sysfs unbind file can be used to unbind the driver from the
  device. This can happen any time.

Signed-off-by: Noralf Trønnes <[e-mail]>
---
 drivers/gpu/drm/tinydrm/hx8357d.c  |  9 +++++--
 drivers/gpu/drm/tinydrm/ili9225.c  | 24 ++++++++++++++---
 drivers/gpu/drm/tinydrm/ili9341.c  |  9 +++++--
 drivers/gpu/drm/tinydrm/mi0283qt.c |  9 +++++--
 drivers/gpu/drm/tinydrm/mipi-dbi.c | 39 +++++++++++++++++++++++----
 drivers/gpu/drm/tinydrm/repaper.c  | 42 +++++++++++++++++++++---------
 drivers/gpu/drm/tinydrm/st7586.c   | 23 +++++++++++++---
 drivers/gpu/drm/tinydrm/st7735r.c  |  9 +++++--
 8 files changed, 131 insertions(+), 33 deletions(-)

Patch

diff --git a/drivers/gpu/drm/tinydrm/hx8357d.c b/drivers/gpu/drm/tinydrm/hx8357d.c
index 4648bd6d6282..aac2c4bda779 100644
--- a/drivers/gpu/drm/tinydrm/hx8357d.c
+++ b/drivers/gpu/drm/tinydrm/hx8357d.c
@@ -49,13 +49,16 @@  static void yx240qv29_enable(struct drm_simple_display_pipe *pipe,
 {
 	struct mipi_dbi *mipi = drm_to_mipi_dbi(pipe->crtc.dev);
 	u8 addr_mode;
-	int ret;
+	int ret, idx;
+
+	if (!drm_dev_enter(pipe->crtc.dev, &idx))
+		return;
 
 	DRM_DEBUG_KMS("\n");
 
 	ret = mipi_dbi_poweron_conditional_reset(mipi);
 	if (ret < 0)
-		return;
+		goto out_exit;
 	if (ret == 1)
 		goto out_enable;
 
@@ -171,6 +174,8 @@  static void yx240qv29_enable(struct drm_simple_display_pipe *pipe,
 	}
 	mipi_dbi_command(mipi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
 	mipi_dbi_enable_flush(mipi, crtc_state, plane_state);
+out_exit:
+	drm_dev_exit(idx);
 }
 
 static const struct drm_simple_display_pipe_funcs hx8357d_pipe_funcs = {
diff --git a/drivers/gpu/drm/tinydrm/ili9225.c b/drivers/gpu/drm/tinydrm/ili9225.c
index 20a44a43a64a..9dfc472032ae 100644
--- a/drivers/gpu/drm/tinydrm/ili9225.c
+++ b/drivers/gpu/drm/tinydrm/ili9225.c
@@ -88,13 +88,16 @@  static void ili9225_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
 	bool swap = mipi->swap_bytes;
 	u16 x_start, y_start;
 	u16 x1, x2, y1, y2;
-	int ret = 0;
+	int idx, ret = 0;
 	bool full;
 	void *tr;
 
 	if (!mipi->enabled)
 		return;
 
+	if (!drm_dev_enter(fb->dev, &idx))
+		return;
+
 	full = width == fb->width && height == fb->height;
 
 	DRM_DEBUG_KMS("Flushing [FB:%d] " DRM_RECT_FMT "\n", fb->base.id, DRM_RECT_ARG(rect));
@@ -157,6 +160,8 @@  static void ili9225_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
 err_msg:
 	if (ret)
 		dev_err_once(fb->dev->dev, "Failed to update display %d\n", ret);
+
+	drm_dev_exit(idx);
 }
 
 static void ili9225_pipe_update(struct drm_simple_display_pipe *pipe,
@@ -190,9 +195,12 @@  static void ili9225_pipe_enable(struct drm_simple_display_pipe *pipe,
 		.y1 = 0,
 		.y2 = fb->height,
 	};
-	int ret;
+	int ret, idx;
 	u8 am_id;
 
+	if (!drm_dev_enter(pipe->crtc.dev, &idx))
+		return;
+
 	DRM_DEBUG_KMS("\n");
 
 	mipi_dbi_hw_reset(mipi);
@@ -206,7 +214,7 @@  static void ili9225_pipe_enable(struct drm_simple_display_pipe *pipe,
 	ret = ili9225_command(mipi, ILI9225_POWER_CONTROL_1, 0x0000);
 	if (ret) {
 		DRM_DEV_ERROR(dev, "Error sending command %d\n", ret);
-		return;
+		goto out_exit;
 	}
 	ili9225_command(mipi, ILI9225_POWER_CONTROL_2, 0x0000);
 	ili9225_command(mipi, ILI9225_POWER_CONTROL_3, 0x0000);
@@ -279,16 +287,22 @@  static void ili9225_pipe_enable(struct drm_simple_display_pipe *pipe,
 
 	mipi->enabled = true;
 	ili9225_fb_dirty(fb, &rect);
+out_exit:
+	drm_dev_exit(idx);
 }
 
 static void ili9225_pipe_disable(struct drm_simple_display_pipe *pipe)
 {
 	struct mipi_dbi *mipi = drm_to_mipi_dbi(pipe->crtc.dev);
+	int idx;
+
+	if (!drm_dev_enter(pipe->crtc.dev, &idx))
+		return;
 
 	DRM_DEBUG_KMS("\n");
 
 	if (!mipi->enabled)
-		return;
+		goto out_exit;
 
 	ili9225_command(mipi, ILI9225_DISPLAY_CONTROL_1, 0x0000);
 	msleep(50);
@@ -297,6 +311,8 @@  static void ili9225_pipe_disable(struct drm_simple_display_pipe *pipe)
 	ili9225_command(mipi, ILI9225_POWER_CONTROL_1, 0x0a02);
 
 	mipi->enabled = false;
+out_exit:
+	drm_dev_exit(idx);
 }
 
 static int ili9225_dbi_command(struct mipi_dbi *mipi, u8 cmd, u8 *par,
diff --git a/drivers/gpu/drm/tinydrm/ili9341.c b/drivers/gpu/drm/tinydrm/ili9341.c
index 5ab3267b224a..70b4396f400b 100644
--- a/drivers/gpu/drm/tinydrm/ili9341.c
+++ b/drivers/gpu/drm/tinydrm/ili9341.c
@@ -55,13 +55,16 @@  static void yx240qv29_enable(struct drm_simple_display_pipe *pipe,
 {
 	struct mipi_dbi *mipi = drm_to_mipi_dbi(pipe->crtc.dev);
 	u8 addr_mode;
-	int ret;
+	int ret, idx;
+
+	if (!drm_dev_enter(pipe->crtc.dev, &idx))
+		return;
 
 	DRM_DEBUG_KMS("\n");
 
 	ret = mipi_dbi_poweron_conditional_reset(mipi);
 	if (ret < 0)
-		return;
+		goto out_exit;
 	if (ret == 1)
 		goto out_enable;
 
@@ -127,6 +130,8 @@  static void yx240qv29_enable(struct drm_simple_display_pipe *pipe,
 	addr_mode |= ILI9341_MADCTL_BGR;
 	mipi_dbi_command(mipi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
 	mipi_dbi_enable_flush(mipi, crtc_state, plane_state);
+out_exit:
+	drm_dev_exit(idx);
 }
 
 static const struct drm_simple_display_pipe_funcs ili9341_pipe_funcs = {
diff --git a/drivers/gpu/drm/tinydrm/mi0283qt.c b/drivers/gpu/drm/tinydrm/mi0283qt.c
index bb0ce4514e60..7d0bcf5de89f 100644
--- a/drivers/gpu/drm/tinydrm/mi0283qt.c
+++ b/drivers/gpu/drm/tinydrm/mi0283qt.c
@@ -57,13 +57,16 @@  static void mi0283qt_enable(struct drm_simple_display_pipe *pipe,
 {
 	struct mipi_dbi *mipi = drm_to_mipi_dbi(pipe->crtc.dev);
 	u8 addr_mode;
-	int ret;
+	int ret, idx;
+
+	if (!drm_dev_enter(pipe->crtc.dev, &idx))
+		return;
 
 	DRM_DEBUG_KMS("\n");
 
 	ret = mipi_dbi_poweron_conditional_reset(mipi);
 	if (ret < 0)
-		return;
+		goto out_exit;
 	if (ret == 1)
 		goto out_enable;
 
@@ -135,6 +138,8 @@  static void mi0283qt_enable(struct drm_simple_display_pipe *pipe,
 	addr_mode |= ILI9341_MADCTL_BGR;
 	mipi_dbi_command(mipi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
 	mipi_dbi_enable_flush(mipi, crtc_state, plane_state);
+out_exit:
+	drm_dev_exit(idx);
 }
 
 static const struct drm_simple_display_pipe_funcs mi0283qt_pipe_funcs = {
diff --git a/drivers/gpu/drm/tinydrm/mipi-dbi.c b/drivers/gpu/drm/tinydrm/mipi-dbi.c
index 861e04815104..df473b31082c 100644
--- a/drivers/gpu/drm/tinydrm/mipi-dbi.c
+++ b/drivers/gpu/drm/tinydrm/mipi-dbi.c
@@ -220,13 +220,16 @@  static void mipi_dbi_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
 	unsigned int height = rect->y2 - rect->y1;
 	unsigned int width = rect->x2 - rect->x1;
 	bool swap = mipi->swap_bytes;
-	int ret = 0;
+	int idx, ret = 0;
 	bool full;
 	void *tr;
 
 	if (!mipi->enabled)
 		return;
 
+	if (!drm_dev_enter(fb->dev, &idx))
+		return;
+
 	full = width == fb->width && height == fb->height;
 
 	DRM_DEBUG_KMS("Flushing [FB:%d] " DRM_RECT_FMT "\n", fb->base.id, DRM_RECT_ARG(rect));
@@ -253,6 +256,8 @@  static void mipi_dbi_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
 err_msg:
 	if (ret)
 		dev_err_once(fb->dev->dev, "Failed to update display %d\n", ret);
+
+	drm_dev_exit(idx);
 }
 
 /**
@@ -307,10 +312,16 @@  void mipi_dbi_enable_flush(struct mipi_dbi *mipi,
 		.y1 = 0,
 		.y2 = fb->height,
 	};
+	int idx;
+
+	if (!drm_dev_enter(&mipi->base, &idx))
+		return;
 
 	mipi->enabled = true;
 	mipi_dbi_fb_dirty(fb, &rect);
 	backlight_enable(mipi->backlight);
+
+	drm_dev_exit(idx);
 }
 EXPORT_SYMBOL(mipi_dbi_enable_flush);
 
@@ -342,6 +353,10 @@  static void mipi_dbi_blank(struct mipi_dbi *mipi)
 void mipi_dbi_pipe_disable(struct drm_simple_display_pipe *pipe)
 {
 	struct mipi_dbi *mipi = drm_to_mipi_dbi(pipe->crtc.dev);
+	int idx;
+
+	if (!drm_dev_enter(pipe->crtc.dev, &idx))
+		return;
 
 	DRM_DEBUG_KMS("\n");
 
@@ -354,6 +369,8 @@  void mipi_dbi_pipe_disable(struct drm_simple_display_pipe *pipe)
 
 	if (mipi->regulator)
 		regulator_disable(mipi->regulator);
+
+	drm_dev_exit(idx);
 }
 EXPORT_SYMBOL(mipi_dbi_pipe_disable);
 
@@ -995,11 +1012,16 @@  static ssize_t mipi_dbi_debugfs_command_write(struct file *file,
 	u8 val, cmd = 0, parameters[64];
 	char *buf, *pos, *token;
 	unsigned int i;
-	int ret;
+	int ret, idx;
+
+	if (!drm_dev_enter(&mipi->base, &idx))
+		return -ENODEV;
 
 	buf = memdup_user_nul(ubuf, count);
-	if (IS_ERR(buf))
-		return PTR_ERR(buf);
+	if (IS_ERR(buf)) {
+		ret = PTR_ERR(buf);
+		goto err_exit;
+	}
 
 	/* strip trailing whitespace */
 	for (i = count - 1; i > 0; i--)
@@ -1035,6 +1057,8 @@  static ssize_t mipi_dbi_debugfs_command_write(struct file *file,
 
 err_free:
 	kfree(buf);
+err_exit:
+	drm_dev_exit(idx);
 
 	return ret < 0 ? ret : count;
 }
@@ -1043,8 +1067,11 @@  static int mipi_dbi_debugfs_command_show(struct seq_file *m, void *unused)
 {
 	struct mipi_dbi *mipi = m->private;
 	u8 cmd, val[4];
+	int ret, idx;
 	size_t len;
-	int ret;
+
+	if (!drm_dev_enter(&mipi->base, &idx))
+		return -ENODEV;
 
 	for (cmd = 0; cmd < 255; cmd++) {
 		if (!mipi_dbi_command_is_read(mipi, cmd))
@@ -1075,6 +1102,8 @@  static int mipi_dbi_debugfs_command_show(struct seq_file *m, void *unused)
 		seq_printf(m, "%*phN\n", (int)len, val);
 	}
 
+	drm_dev_exit(idx);
+
 	return 0;
 }
 
diff --git a/drivers/gpu/drm/tinydrm/repaper.c b/drivers/gpu/drm/tinydrm/repaper.c
index 4c8205565668..9451583867e4 100644
--- a/drivers/gpu/drm/tinydrm/repaper.c
+++ b/drivers/gpu/drm/tinydrm/repaper.c
@@ -532,8 +532,14 @@  static int repaper_fb_dirty(struct drm_framebuffer *fb)
 	struct dma_buf_attachment *import_attach = cma_obj->base.import_attach;
 	struct repaper_epd *epd = drm_to_epd(fb->dev);
 	struct drm_rect clip;
+	int idx, ret = 0;
 	u8 *buf = NULL;
-	int ret = 0;
+
+	if (!epd->enabled)
+		return 0;
+
+	if (!drm_dev_enter(fb->dev, &idx))
+		return -ENODEV;
 
 	/* repaper can't do partial updates */
 	clip.x1 = 0;
@@ -541,17 +547,16 @@  static int repaper_fb_dirty(struct drm_framebuffer *fb)
 	clip.y1 = 0;
 	clip.y2 = fb->height;
 
-	if (!epd->enabled)
-		return 0;
-
 	repaper_get_temperature(epd);
 
 	DRM_DEBUG("Flushing [FB:%d] st=%ums\n", fb->base.id,
 		  epd->factored_stage_time);
 
 	buf = kmalloc_array(fb->width, fb->height, GFP_KERNEL);
-	if (!buf)
-		return -ENOMEM;
+	if (!buf) {
+		ret = -ENOMEM;
+		goto out_exit;
+	}
 
 	if (import_attach) {
 		ret = dma_buf_begin_cpu_access(import_attach->dmabuf,
@@ -620,6 +625,8 @@  static int repaper_fb_dirty(struct drm_framebuffer *fb)
 
 out_free:
 	kfree(buf);
+out_exit:
+	drm_dev_exit(idx);
 
 	return ret;
 }
@@ -649,7 +656,10 @@  static void repaper_pipe_enable(struct drm_simple_display_pipe *pipe,
 	struct spi_device *spi = epd->spi;
 	struct device *dev = &spi->dev;
 	bool dc_ok = false;
-	int i, ret;
+	int i, ret, idx;
+
+	if (!drm_dev_enter(pipe->crtc.dev, &idx))
+		return;
 
 	DRM_DEBUG_DRIVER("\n");
 
@@ -688,7 +698,7 @@  static void repaper_pipe_enable(struct drm_simple_display_pipe *pipe,
 	if (!i) {
 		DRM_DEV_ERROR(dev, "timeout waiting for panel to become ready.\n");
 		power_off(epd);
-		return;
+		goto out_exit;
 	}
 
 	repaper_read_id(spi);
@@ -699,7 +709,7 @@  static void repaper_pipe_enable(struct drm_simple_display_pipe *pipe,
 		else
 			dev_err(dev, "wrong COG ID 0x%02x\n", ret);
 		power_off(epd);
-		return;
+		goto out_exit;
 	}
 
 	/* Disable OE */
@@ -712,7 +722,7 @@  static void repaper_pipe_enable(struct drm_simple_display_pipe *pipe,
 		else
 			DRM_DEV_ERROR(dev, "panel is reported broken\n");
 		power_off(epd);
-		return;
+		goto out_exit;
 	}
 
 	/* Power saving mode */
@@ -752,7 +762,7 @@  static void repaper_pipe_enable(struct drm_simple_display_pipe *pipe,
 		if (ret < 0) {
 			DRM_DEV_ERROR(dev, "failed to read chip (%d)\n", ret);
 			power_off(epd);
-			return;
+			goto out_exit;
 		}
 
 		if (ret & 0x40) {
@@ -764,7 +774,7 @@  static void repaper_pipe_enable(struct drm_simple_display_pipe *pipe,
 	if (!dc_ok) {
 		DRM_DEV_ERROR(dev, "dc/dc failed\n");
 		power_off(epd);
-		return;
+		goto out_exit;
 	}
 
 	/*
@@ -775,6 +785,8 @@  static void repaper_pipe_enable(struct drm_simple_display_pipe *pipe,
 
 	epd->enabled = true;
 	epd->partial = false;
+out_exit:
+	drm_dev_exit(idx);
 }
 
 static void repaper_pipe_disable(struct drm_simple_display_pipe *pipe)
@@ -782,6 +794,10 @@  static void repaper_pipe_disable(struct drm_simple_display_pipe *pipe)
 	struct repaper_epd *epd = drm_to_epd(pipe->crtc.dev);
 	struct spi_device *spi = epd->spi;
 	unsigned int line;
+	int idx;
+
+	if (!drm_dev_enter(pipe->crtc.dev, &idx))
+		return;
 
 	DRM_DEBUG_DRIVER("\n");
 
@@ -826,6 +842,8 @@  static void repaper_pipe_disable(struct drm_simple_display_pipe *pipe)
 	msleep(50);
 
 	power_off(epd);
+
+	drm_dev_exit(idx);
 }
 
 static void repaper_pipe_update(struct drm_simple_display_pipe *pipe,
diff --git a/drivers/gpu/drm/tinydrm/st7586.c b/drivers/gpu/drm/tinydrm/st7586.c
index cae003318b42..646b55d4fcd0 100644
--- a/drivers/gpu/drm/tinydrm/st7586.c
+++ b/drivers/gpu/drm/tinydrm/st7586.c
@@ -118,12 +118,14 @@  static int st7586_buf_copy(void *dst, struct drm_framebuffer *fb,
 static void st7586_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
 {
 	struct mipi_dbi *mipi = drm_to_mipi_dbi(fb->dev);
-	int start, end;
-	int ret = 0;
+	int start, end, idx, ret = 0;
 
 	if (!mipi->enabled)
 		return;
 
+	if (!drm_dev_enter(fb->dev, &idx))
+		return;
+
 	/* 3 pixels per byte, so grow clip to nearest multiple of 3 */
 	rect->x1 = rounddown(rect->x1, 3);
 	rect->x2 = roundup(rect->x2, 3);
@@ -151,6 +153,8 @@  static void st7586_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
 err_msg:
 	if (ret)
 		dev_err_once(fb->dev->dev, "Failed to update display %d\n", ret);
+
+	drm_dev_exit(idx);
 }
 
 static void st7586_pipe_update(struct drm_simple_display_pipe *pipe,
@@ -183,14 +187,17 @@  static void st7586_pipe_enable(struct drm_simple_display_pipe *pipe,
 		.y1 = 0,
 		.y2 = fb->height,
 	};
-	int ret;
+	int idx, ret;
 	u8 addr_mode;
 
+	if (!drm_dev_enter(pipe->crtc.dev, &idx))
+		return;
+
 	DRM_DEBUG_KMS("\n");
 
 	ret = mipi_dbi_poweron_reset(mipi);
 	if (ret)
-		return;
+		goto out_exit;
 
 	mipi_dbi_command(mipi, ST7586_AUTO_READ_CTRL, 0x9f);
 	mipi_dbi_command(mipi, ST7586_OTP_RW_CTRL, 0x00);
@@ -243,11 +250,17 @@  static void st7586_pipe_enable(struct drm_simple_display_pipe *pipe,
 	st7586_fb_dirty(fb, &rect);
 
 	mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_ON);
+out_exit:
+	drm_dev_exit(idx);
 }
 
 static void st7586_pipe_disable(struct drm_simple_display_pipe *pipe)
 {
 	struct mipi_dbi *mipi = drm_to_mipi_dbi(pipe->crtc.dev);
+	int idx;
+
+	if (!drm_dev_enter(pipe->crtc.dev, &idx))
+		return;
 
 	DRM_DEBUG_KMS("\n");
 
@@ -256,6 +269,8 @@  static void st7586_pipe_disable(struct drm_simple_display_pipe *pipe)
 
 	mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_OFF);
 	mipi->enabled = false;
+
+	drm_dev_exit(idx);
 }
 
 static const u32 st7586_formats[] = {
diff --git a/drivers/gpu/drm/tinydrm/st7735r.c b/drivers/gpu/drm/tinydrm/st7735r.c
index dcd07248884c..380d26a1b807 100644
--- a/drivers/gpu/drm/tinydrm/st7735r.c
+++ b/drivers/gpu/drm/tinydrm/st7735r.c
@@ -43,14 +43,17 @@  static void jd_t18003_t01_pipe_enable(struct drm_simple_display_pipe *pipe,
 				      struct drm_plane_state *plane_state)
 {
 	struct mipi_dbi *mipi = drm_to_mipi_dbi(pipe->crtc.dev);
-	int ret;
+	int ret, idx;
 	u8 addr_mode;
 
+	if (!drm_dev_enter(pipe->crtc.dev, &idx))
+		return;
+
 	DRM_DEBUG_KMS("\n");
 
 	ret = mipi_dbi_poweron_reset(mipi);
 	if (ret)
-		return;
+		goto out_exit;
 
 	msleep(150);
 
@@ -101,6 +104,8 @@  static void jd_t18003_t01_pipe_enable(struct drm_simple_display_pipe *pipe,
 	msleep(20);
 
 	mipi_dbi_enable_flush(mipi, crtc_state, plane_state);
+out_exit:
+	drm_dev_exit(idx);
 }
 
 static const struct drm_simple_display_pipe_funcs jd_t18003_t01_pipe_funcs = {