drm/amd/display: Try RGB before YCbCr 4:4:4 in stream validationgrafted

amdgpu_dm_create_validate_stream_for_sink() walks encoding_order[] and
uses the first encoding that validates. YCbCr 4:4:4 is listed before
RGB, so an HDMI sink that advertises 4:4:4 gets YCbCr 4:4:4 whenever the
"color format" property is left at AUTO, even though RGB fits the same
link.

That contradicts the documented AUTO behaviour for HDMI in enum
drm_connector_color_format (RGB, falling back to YCbCr 4:2:0 only when
the bandwidth is not available or the mode is 4:2:0-only), which the
amdgpu implementation of the property also describes. It also leaves
the "Broadcast RGB" property without effect on such sinks, since the
quantization range it selects only applies to RGB output.

Try RGB first. The mask still holds every encoding the sink supports,
so a mode that cannot carry RGB falls back exactly as before.

For reference, v7.2 picked RGB here unless YCbCr 4:4:4 was forced
through debugfs, while earlier kernels picked YCbCr 4:4:4 for any HDMI
sink that advertised it.

Fixes: 0b0ff65d3ca1 ("drm/amd/display: Refactor stream validation")
Suggested-by: Adolfo Rodrigues <adolfotregosa@gmail.com>
Assisted-by: Claude Code:claude-fable-5-1
Signed-off-by: Adrian Betschart <adrian.betschart@cinemaone.ch>
Reviewed-by: Fangzhi Zuo <jerry.zuo@amd.com>
Tested-by: Adolfo Rodrigues <adolfotregosa@gmail.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 7de432bc753133764dc40d37f9388da56de251e7)

1 files changed, 170 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-ep93xx.c b/drivers/rtc/rtc-ep93xx.c
new file mode 100644
index 000000000..507c9f220
--- /dev/null
+++ b/drivers/rtc/rtc-ep93xx.c
@@ -0,0 +1,170 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * A driver for the RTC embedded in the Cirrus Logic EP93XX processors
+ * Copyright (c) 2006 Tower Technologies
+ *
+ * Author: Alessandro Zummo <a.zummo@towertech.it>
+ */
+
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/gfp.h>
+
+#define EP93XX_RTC_DATA			0x000
+#define EP93XX_RTC_MATCH		0x004
+#define EP93XX_RTC_STATUS		0x008
+#define  EP93XX_RTC_STATUS_INTR		 BIT(0)
+#define EP93XX_RTC_LOAD			0x00C
+#define EP93XX_RTC_CONTROL		0x010
+#define  EP93XX_RTC_CONTROL_MIE		 BIT(0)
+#define EP93XX_RTC_SWCOMP		0x108
+#define  EP93XX_RTC_SWCOMP_DEL_MASK	 0x001f0000
+#define  EP93XX_RTC_SWCOMP_DEL_SHIFT	 16
+#define  EP93XX_RTC_SWCOMP_INT_MASK	 0x0000ffff
+#define  EP93XX_RTC_SWCOMP_INT_SHIFT	 0
+
+struct ep93xx_rtc {
+	void __iomem	*mmio_base;
+};
+
+static int ep93xx_rtc_get_swcomp(struct device *dev, unsigned short *preload,
+				 unsigned short *delete)
+{
+	struct ep93xx_rtc *ep93xx_rtc = dev_get_drvdata(dev);
+	unsigned long comp;
+
+	comp = readl(ep93xx_rtc->mmio_base + EP93XX_RTC_SWCOMP);
+
+	if (preload)
+		*preload = (comp & EP93XX_RTC_SWCOMP_INT_MASK)
+				>> EP93XX_RTC_SWCOMP_INT_SHIFT;
+
+	if (delete)
+		*delete = (comp & EP93XX_RTC_SWCOMP_DEL_MASK)
+				>> EP93XX_RTC_SWCOMP_DEL_SHIFT;
+
+	return 0;
+}
+
+static int ep93xx_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct ep93xx_rtc *ep93xx_rtc = dev_get_drvdata(dev);
+	unsigned long time;
+
+	time = readl(ep93xx_rtc->mmio_base + EP93XX_RTC_DATA);
+
+	rtc_time64_to_tm(time, tm);
+	return 0;
+}
+
+static int ep93xx_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct ep93xx_rtc *ep93xx_rtc = dev_get_drvdata(dev);
+	unsigned long secs = rtc_tm_to_time64(tm);
+
+	writel(secs + 1, ep93xx_rtc->mmio_base + EP93XX_RTC_LOAD);
+	return 0;
+}
+
+static int ep93xx_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+	unsigned short preload, delete;
+
+	ep93xx_rtc_get_swcomp(dev, &preload, &delete);
+
+	seq_printf(seq, "preload\t\t: %d\n", preload);
+	seq_printf(seq, "delete\t\t: %d\n", delete);
+
+	return 0;
+}
+
+static const struct rtc_class_ops ep93xx_rtc_ops = {
+	.read_time	= ep93xx_rtc_read_time,
+	.set_time	= ep93xx_rtc_set_time,
+	.proc		= ep93xx_rtc_proc,
+};
+
+static ssize_t comp_preload_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	unsigned short preload;
+
+	ep93xx_rtc_get_swcomp(dev->parent, &preload, NULL);
+
+	return sprintf(buf, "%d\n", preload);
+}
+static DEVICE_ATTR_RO(comp_preload);
+
+static ssize_t comp_delete_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	unsigned short delete;
+
+	ep93xx_rtc_get_swcomp(dev->parent, NULL, &delete);
+
+	return sprintf(buf, "%d\n", delete);
+}
+static DEVICE_ATTR_RO(comp_delete);
+
+static struct attribute *ep93xx_rtc_attrs[] = {
+	&dev_attr_comp_preload.attr,
+	&dev_attr_comp_delete.attr,
+	NULL
+};
+
+static const struct attribute_group ep93xx_rtc_sysfs_files = {
+	.attrs	= ep93xx_rtc_attrs,
+};
+
+static int ep93xx_rtc_probe(struct platform_device *pdev)
+{
+	struct ep93xx_rtc *ep93xx_rtc;
+	struct rtc_device *rtc;
+	int err;
+
+	ep93xx_rtc = devm_kzalloc(&pdev->dev, sizeof(*ep93xx_rtc), GFP_KERNEL);
+	if (!ep93xx_rtc)
+		return -ENOMEM;
+
+	ep93xx_rtc->mmio_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(ep93xx_rtc->mmio_base))
+		return PTR_ERR(ep93xx_rtc->mmio_base);
+
+	platform_set_drvdata(pdev, ep93xx_rtc);
+
+	rtc = devm_rtc_allocate_device(&pdev->dev);
+	if (IS_ERR(rtc))
+		return PTR_ERR(rtc);
+
+	rtc->ops = &ep93xx_rtc_ops;
+	rtc->range_max = U32_MAX;
+
+	err = rtc_add_group(rtc, &ep93xx_rtc_sysfs_files);
+	if (err)
+		return err;
+
+	return devm_rtc_register_device(rtc);
+}
+
+static const struct of_device_id ep93xx_rtc_of_ids[] = {
+	{ .compatible = "cirrus,ep9301-rtc" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ep93xx_rtc_of_ids);
+
+static struct platform_driver ep93xx_rtc_driver = {
+	.driver		= {
+		.name	= "ep93xx-rtc",
+		.of_match_table = ep93xx_rtc_of_ids,
+	},
+	.probe		= ep93xx_rtc_probe,
+};
+
+module_platform_driver(ep93xx_rtc_driver);
+
+MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
+MODULE_DESCRIPTION("EP93XX RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ep93xx-rtc");