fsi: Add regmap and refactor sbefifo

Merge series from Eddie James <eajames@linux.ibm.com>:

The SBEFIFO hardware can now be attached over a new I2C endpoint interface
called the I2C Responder (I2CR). In order to use the existing SBEFIFO
driver, add a regmap driver for the FSI bus and an endpoint driver for the
I2CR. Then, refactor the SBEFIFO and OCC drivers to clean up and use the
new regmap driver or the I2CR interface.

This branch just has the regmap change so it can be shared with the FSI
code.

1 files changed, 47 insertions, 19 deletions

diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c
index e2f76621453c..3ee59bae9d2f 100644
--- a/drivers/gpu/drm/drm_format_helper.c
+++ b/drivers/gpu/drm/drm_format_helper.c
@@ -807,6 +807,38 @@ static bool is_listed_fourcc(const uint32_t *fourccs, size_t nfourccs, uint32_t
 	return false;
 }
 
+static const uint32_t conv_from_xrgb8888[] = {
+	DRM_FORMAT_XRGB8888,
+	DRM_FORMAT_ARGB8888,
+	DRM_FORMAT_XRGB2101010,
+	DRM_FORMAT_ARGB2101010,
+	DRM_FORMAT_RGB565,
+	DRM_FORMAT_RGB888,
+};
+
+static const uint32_t conv_from_rgb565_888[] = {
+	DRM_FORMAT_XRGB8888,
+	DRM_FORMAT_ARGB8888,
+};
+
+static bool is_conversion_supported(uint32_t from, uint32_t to)
+{
+	switch (from) {
+	case DRM_FORMAT_XRGB8888:
+	case DRM_FORMAT_ARGB8888:
+		return is_listed_fourcc(conv_from_xrgb8888, ARRAY_SIZE(conv_from_xrgb8888), to);
+	case DRM_FORMAT_RGB565:
+	case DRM_FORMAT_RGB888:
+		return is_listed_fourcc(conv_from_rgb565_888, ARRAY_SIZE(conv_from_rgb565_888), to);
+	case DRM_FORMAT_XRGB2101010:
+		return to == DRM_FORMAT_ARGB2101010;
+	case DRM_FORMAT_ARGB2101010:
+		return to == DRM_FORMAT_XRGB2101010;
+	default:
+		return false;
+	}
+}
+
 /**
  * drm_fb_build_fourcc_list - Filters a list of supported color formats against
  *                            the device's native formats
@@ -827,7 +859,9 @@ static bool is_listed_fourcc(const uint32_t *fourccs, size_t nfourccs, uint32_t
  * be handed over to drm_universal_plane_init() et al. Native formats
  * will go before emulated formats. Other heuristics might be applied
  * to optimize the order. Formats near the beginning of the list are
- * usually preferred over formats near the end of the list.
+ * usually preferred over formats near the end of the list. Formats
+ * without conversion helpers will be skipped. New drivers should only
+ * pass in XRGB8888 and avoid exposing additional emulated formats.
  *
  * Returns:
  * The number of color-formats 4CC codes returned in @fourccs_out.
@@ -839,7 +873,7 @@ size_t drm_fb_build_fourcc_list(struct drm_device *dev,
 {
 	u32 *fourccs = fourccs_out;
 	const u32 *fourccs_end = fourccs_out + nfourccs_out;
-	bool found_native = false;
+	uint32_t native_format = 0;
 	size_t i;
 
 	/*
@@ -858,27 +892,19 @@ size_t drm_fb_build_fourcc_list(struct drm_device *dev,
 
 		drm_dbg_kms(dev, "adding native format %p4cc\n", &fourcc);
 
-		if (!found_native)
-			found_native = is_listed_fourcc(driver_fourccs, driver_nfourccs, fourcc);
+		/*
+		 * There should only be one native format with the current API.
+		 * This API needs to be refactored to correctly support arbitrary
+		 * sets of native formats, since it needs to report which native
+		 * format to use for each emulated format.
+		 */
+		if (!native_format)
+			native_format = fourcc;
 		*fourccs = fourcc;
 		++fourccs;
 	}
 
 	/*
-	 * The plane's atomic_update helper converts the framebuffer's color format
-	 * to a native format when copying to device memory.
-	 *
-	 * If there is not a single format supported by both, device and
-	 * driver, the native formats are likely not supported by the conversion
-	 * helpers. Therefore *only* support the native formats and add a
-	 * conversion helper ASAP.
-	 */
-	if (!found_native) {
-		drm_warn(dev, "Format conversion helpers required to add extra formats.\n");
-		goto out;
-	}
-
-	/*
 	 * The extra formats, emulated by the driver, go second.
 	 */
 
@@ -890,6 +916,9 @@ size_t drm_fb_build_fourcc_list(struct drm_device *dev,
 		} else if (fourccs == fourccs_end) {
 			drm_warn(dev, "Ignoring emulated format %p4cc\n", &fourcc);
 			continue; /* end of available output buffer */
+		} else if (!is_conversion_supported(fourcc, native_format)) {
+			drm_dbg_kms(dev, "Unsupported emulated format %p4cc\n", &fourcc);
+			continue; /* format is not supported for conversion */
 		}
 
 		drm_dbg_kms(dev, "adding emulated format %p4cc\n", &fourcc);
@@ -898,7 +927,6 @@ size_t drm_fb_build_fourcc_list(struct drm_device *dev,
 		++fourccs;
 	}
 
-out:
 	return fourccs - fourccs_out;
 }
 EXPORT_SYMBOL(drm_fb_build_fourcc_list);