drm/vc4: tests: Fail the current test if we access a register

Accessing a register when running under kunit is a bad idea since our
device is completely mocked.

Fail the current test if we ever access any of our hardware registers.
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Maíra Canal <mcanal@igalia.com>
Link: https://lore.kernel.org/r/20221123-rpi-kunit-tests-v3-18-4615a663a84a@cerno.techSigned-off-by: Maxime Ripard <maxime@cerno.tech>

drivers/gpu/drm/vc4/vc4_crtc.c

@@ -50,8 +50,17 @@
 
 #define HVS_FIFO_LATENCY_PIX	6
 
-#define CRTC_WRITE(offset, val) writel(val, vc4_crtc->regs + (offset))
-#define CRTC_READ(offset) readl(vc4_crtc->regs + (offset))
+#define CRTC_WRITE(offset, val)								\
+	do {										\
+		kunit_fail_current_test("Accessing a register in a unit test!\n");	\
+		writel(val, vc4_crtc->regs + (offset));					\
+	} while (0)
+
+#define CRTC_READ(offset)								\
+	({										\
+		kunit_fail_current_test("Accessing a register in a unit test!\n");	\
+		readl(vc4_crtc->regs + (offset));					\
+	})
 
 static const struct debugfs_reg32 crtc_regs[] = {
 	VC4_REG32(PV_CONTROL),

drivers/gpu/drm/vc4/vc4_dpi.c

@@ -103,8 +103,17 @@ to_vc4_dpi(struct drm_encoder *encoder)
 	return container_of(encoder, struct vc4_dpi, encoder.base);
 }
 
-#define DPI_READ(offset) readl(dpi->regs + (offset))
-#define DPI_WRITE(offset, val) writel(val, dpi->regs + (offset))
+#define DPI_READ(offset)								\
+	({										\
+		kunit_fail_current_test("Accessing a register in a unit test!\n");	\
+		readl(dpi->regs + (offset));						\
+	})
+
+#define DPI_WRITE(offset, val)								\
+	do {										\
+		kunit_fail_current_test("Accessing a register in a unit test!\n");	\
+		writel(val, dpi->regs + (offset));					\
+	} while (0)
 
 static const struct debugfs_reg32 dpi_regs[] = {
 	VC4_REG32(DPI_C),

drivers/gpu/drm/vc4/vc4_drv.h

@@ -19,6 +19,8 @@
 #include <drm/drm_mm.h>
 #include <drm/drm_modeset_lock.h>
 
+#include <kunit/test-bug.h>
+
 #include "uapi/drm/vc4_drm.h"
 
 struct drm_device;
@@ -645,10 +647,29 @@ to_vc4_crtc_state(const struct drm_crtc_state *crtc_state)
 	return container_of(crtc_state, struct vc4_crtc_state, base);
 }
 
-#define V3D_READ(offset) readl(vc4->v3d->regs + offset)
-#define V3D_WRITE(offset, val) writel(val, vc4->v3d->regs + offset)
-#define HVS_READ(offset) readl(hvs->regs + offset)
-#define HVS_WRITE(offset, val) writel(val, hvs->regs + offset)
+#define V3D_READ(offset)								\
+	({										\
+		kunit_fail_current_test("Accessing a register in a unit test!\n");	\
+		readl(vc4->v3d->regs + (offset));						\
+	})
+
+#define V3D_WRITE(offset, val)								\
+	do {										\
+		kunit_fail_current_test("Accessing a register in a unit test!\n");	\
+		writel(val, vc4->v3d->regs + (offset));					\
+	} while (0)
+
+#define HVS_READ(offset)								\
+	({										\
+		kunit_fail_current_test("Accessing a register in a unit test!\n");	\
+		readl(hvs->regs + (offset));						\
+	})
+
+#define HVS_WRITE(offset, val)								\
+	do {										\
+		kunit_fail_current_test("Accessing a register in a unit test!\n");	\
+		writel(val, hvs->regs + (offset));					\
+	} while (0)
 
 #define VC4_REG32(reg) { .name = #reg, .offset = reg }
 

drivers/gpu/drm/vc4/vc4_dsi.c

@@ -617,6 +617,8 @@ dsi_dma_workaround_write(struct vc4_dsi *dsi, u32 offset, u32 val)
 	dma_cookie_t cookie;
 	int ret;
 
+	kunit_fail_current_test("Accessing a register in a unit test!\n");
+
 	/* DSI0 should be able to write normally. */
 	if (!chan) {
 		writel(val, dsi->regs + offset);
@@ -645,7 +647,12 @@ dsi_dma_workaround_write(struct vc4_dsi *dsi, u32 offset, u32 val)
 		DRM_ERROR("Failed to wait for DMA: %d\n", ret);
 }
 
-#define DSI_READ(offset) readl(dsi->regs + (offset))
+#define DSI_READ(offset)								\
+	({										\
+		kunit_fail_current_test("Accessing a register in a unit test!\n");	\
+		readl(dsi->regs + (offset));						\
+	})
+
 #define DSI_WRITE(offset, val) dsi_dma_workaround_write(dsi, offset, val)
 #define DSI_PORT_READ(offset) \
 	DSI_READ(dsi->variant->port ? DSI1_##offset : DSI0_##offset)

drivers/gpu/drm/vc4/vc4_hdmi_regs.h

@@ -456,6 +456,8 @@ static inline u32 vc4_hdmi_read(struct vc4_hdmi *hdmi,
 
 	WARN_ON(pm_runtime_status_suspended(&hdmi->pdev->dev));
 
+	kunit_fail_current_test("Accessing an HDMI register in a unit test!\n");
+
 	if (reg >= variant->num_registers) {
 		dev_warn(&hdmi->pdev->dev,
 			 "Invalid register ID %u\n", reg);
@@ -486,6 +488,8 @@ static inline void vc4_hdmi_write(struct vc4_hdmi *hdmi,
 
 	WARN_ON(pm_runtime_status_suspended(&hdmi->pdev->dev));
 
+	kunit_fail_current_test("Accessing an HDMI register in a unit test!\n");
+
 	if (reg >= variant->num_registers) {
 		dev_warn(&hdmi->pdev->dev,
 			 "Invalid register ID %u\n", reg);

drivers/gpu/drm/vc4/vc4_txp.c

@@ -145,8 +145,17 @@
 /* Number of lines received and committed to memory. */
 #define TXP_PROGRESS		0x10
 
-#define TXP_READ(offset) readl(txp->regs + (offset))
-#define TXP_WRITE(offset, val) writel(val, txp->regs + (offset))
+#define TXP_READ(offset)								\
+	({										\
+		kunit_fail_current_test("Accessing a register in a unit test!\n");	\
+		readl(txp->regs + (offset));						\
+	})
+
+#define TXP_WRITE(offset, val)								\
+	do {										\
+		kunit_fail_current_test("Accessing a register in a unit test!\n");	\
+		writel(val, txp->regs + (offset));					\
+	} while (0)
 
 struct vc4_txp {
 	struct vc4_crtc	base;

drivers/gpu/drm/vc4/vc4_vec.c

@@ -207,8 +207,17 @@ struct vc4_vec {
 	struct debugfs_regset32 regset;
 };
 
-#define VEC_READ(offset) readl(vec->regs + (offset))
-#define VEC_WRITE(offset, val) writel(val, vec->regs + (offset))
+#define VEC_READ(offset)								\
+	({										\
+		kunit_fail_current_test("Accessing a register in a unit test!\n");	\
+		readl(vec->regs + (offset));						\
+	})
+
+#define VEC_WRITE(offset, val)								\
+	do {										\
+		kunit_fail_current_test("Accessing a register in a unit test!\n");	\
+		writel(val, vec->regs + (offset));					\
+	} while (0)
 
 static inline struct vc4_vec *
 encoder_to_vc4_vec(struct drm_encoder *encoder)