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, 144 insertions, 0 deletions

diff --git a/drivers/misc/smpro-misc.c b/drivers/misc/smpro-misc.c
new file mode 100644
index 000000000..2ca5e3bcc
--- /dev/null
+++ b/drivers/misc/smpro-misc.c
@@ -0,0 +1,144 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Ampere Computing SoC's SMpro Misc Driver
+ *
+ * Copyright (c) 2022, Ampere Computing LLC
+ */
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+/* Boot Stage/Progress Registers */
+#define BOOTSTAGE	0xB0
+#define BOOTSTAGE_LO	0xB1
+#define CUR_BOOTSTAGE	0xB2
+#define BOOTSTAGE_HI	0xB3
+
+/* SOC State Registers */
+#define SOC_POWER_LIMIT		0xE5
+
+struct smpro_misc {
+	struct regmap *regmap;
+};
+
+static ssize_t boot_progress_show(struct device *dev, struct device_attribute *da, char *buf)
+{
+	struct smpro_misc *misc = dev_get_drvdata(dev);
+	u16 boot_progress[3] = { 0 };
+	u32 bootstage;
+	u8 boot_stage;
+	u8 cur_stage;
+	u32 reg_lo;
+	u32 reg;
+	int ret;
+
+	/* Read current boot stage */
+	ret = regmap_read(misc->regmap, CUR_BOOTSTAGE, &reg);
+	if (ret)
+		return ret;
+
+	cur_stage = reg & 0xff;
+
+	ret = regmap_read(misc->regmap, BOOTSTAGE, &bootstage);
+	if (ret)
+		return ret;
+
+	boot_stage = (bootstage >> 8) & 0xff;
+
+	if (boot_stage > cur_stage)
+		return -EINVAL;
+
+	ret = regmap_read(misc->regmap,	BOOTSTAGE_LO, &reg_lo);
+	if (!ret)
+		ret = regmap_read(misc->regmap, BOOTSTAGE_HI, &reg);
+	if (ret)
+		return ret;
+
+	/* Firmware to report new boot stage next time */
+	if (boot_stage < cur_stage) {
+		ret = regmap_write(misc->regmap, BOOTSTAGE, ((bootstage & 0xff00) | 0x1));
+		if (ret)
+			return ret;
+	}
+
+	boot_progress[0] = bootstage;
+	boot_progress[1] = swab16(reg);
+	boot_progress[2] = swab16(reg_lo);
+
+	return sysfs_emit(buf, "%*phN\n", (int)sizeof(boot_progress), boot_progress);
+}
+
+static DEVICE_ATTR_RO(boot_progress);
+
+static ssize_t soc_power_limit_show(struct device *dev, struct device_attribute *da, char *buf)
+{
+	struct smpro_misc *misc = dev_get_drvdata(dev);
+	unsigned int value;
+	int ret;
+
+	ret = regmap_read(misc->regmap, SOC_POWER_LIMIT, &value);
+	if (ret)
+		return ret;
+
+	return sysfs_emit(buf, "%d\n", value);
+}
+
+static ssize_t soc_power_limit_store(struct device *dev, struct device_attribute *da,
+				     const char *buf, size_t count)
+{
+	struct smpro_misc *misc = dev_get_drvdata(dev);
+	unsigned long val;
+	s32 ret;
+
+	ret = kstrtoul(buf, 0, &val);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(misc->regmap, SOC_POWER_LIMIT, (unsigned int)val);
+	if (ret)
+		return -EPROTO;
+
+	return count;
+}
+
+static DEVICE_ATTR_RW(soc_power_limit);
+
+static struct attribute *smpro_misc_attrs[] = {
+	&dev_attr_boot_progress.attr,
+	&dev_attr_soc_power_limit.attr,
+	NULL
+};
+
+ATTRIBUTE_GROUPS(smpro_misc);
+
+static int smpro_misc_probe(struct platform_device *pdev)
+{
+	struct smpro_misc *misc;
+
+	misc = devm_kzalloc(&pdev->dev, sizeof(struct smpro_misc), GFP_KERNEL);
+	if (!misc)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, misc);
+
+	misc->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!misc->regmap)
+		return -ENODEV;
+
+	return 0;
+}
+
+static struct platform_driver smpro_misc_driver = {
+	.probe		= smpro_misc_probe,
+	.driver = {
+		.name	= "smpro-misc",
+		.dev_groups = smpro_misc_groups,
+	},
+};
+
+module_platform_driver(smpro_misc_driver);
+
+MODULE_AUTHOR("Tung Nguyen <tungnguyen@os.amperecomputing.com>");
+MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>");
+MODULE_DESCRIPTION("Ampere Altra SMpro Misc driver");
+MODULE_LICENSE("GPL");