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, 221 insertions, 0 deletions

diff --git a/arch/powerpc/mm/cacheflush.c b/arch/powerpc/mm/cacheflush.c
new file mode 100644
index 000000000..7186516ec
--- /dev/null
+++ b/arch/powerpc/mm/cacheflush.c
@@ -0,0 +1,221 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/highmem.h>
+#include <linux/kprobes.h>
+
+/**
+ * flush_coherent_icache() - if a CPU has a coherent icache, flush it
+ * Return true if the cache was flushed, false otherwise
+ */
+static inline bool flush_coherent_icache(void)
+{
+	/*
+	 * For a snooping icache, we still need a dummy icbi to purge all the
+	 * prefetched instructions from the ifetch buffers. We also need a sync
+	 * before the icbi to order the actual stores to memory that might
+	 * have modified instructions with the icbi.
+	 */
+	if (cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) {
+		mb(); /* sync */
+		icbi((void *)PAGE_OFFSET);
+		mb(); /* sync */
+		isync();
+		return true;
+	}
+
+	return false;
+}
+
+/**
+ * invalidate_icache_range() - Flush the icache by issuing icbi across an address range
+ * @start: the start address
+ * @stop: the stop address (exclusive)
+ */
+static void invalidate_icache_range(unsigned long start, unsigned long stop)
+{
+	unsigned long shift = l1_icache_shift();
+	unsigned long bytes = l1_icache_bytes();
+	char *addr = (char *)(start & ~(bytes - 1));
+	unsigned long size = stop - (unsigned long)addr + (bytes - 1);
+	unsigned long i;
+
+	for (i = 0; i < size >> shift; i++, addr += bytes)
+		icbi(addr);
+
+	mb(); /* sync */
+	isync();
+}
+
+/**
+ * flush_icache_range: Write any modified data cache blocks out to memory
+ * and invalidate the corresponding blocks in the instruction cache
+ *
+ * Generic code will call this after writing memory, before executing from it.
+ *
+ * @start: the start address
+ * @stop: the stop address (exclusive)
+ */
+void flush_icache_range(unsigned long start, unsigned long stop)
+{
+	if (flush_coherent_icache())
+		return;
+
+	clean_dcache_range(start, stop);
+
+	if (IS_ENABLED(CONFIG_44x)) {
+		/*
+		 * Flash invalidate on 44x because we are passed kmapped
+		 * addresses and this doesn't work for userspace pages due to
+		 * the virtually tagged icache.
+		 */
+		iccci((void *)start);
+		mb(); /* sync */
+		isync();
+	} else
+		invalidate_icache_range(start, stop);
+}
+EXPORT_SYMBOL(flush_icache_range);
+
+#ifdef CONFIG_HIGHMEM
+/**
+ * flush_dcache_icache_phys() - Flush a page by its physical address
+ * @physaddr: the physical address of the page
+ */
+static void flush_dcache_icache_phys(unsigned long physaddr)
+{
+	unsigned long bytes = l1_dcache_bytes();
+	unsigned long nb = PAGE_SIZE / bytes;
+	unsigned long addr = physaddr & PAGE_MASK;
+	unsigned long msr, msr0;
+	unsigned long loop1 = addr, loop2 = addr;
+
+	msr0 = mfmsr();
+	msr = msr0 & ~MSR_DR;
+	/*
+	 * This must remain as ASM to prevent potential memory accesses
+	 * while the data MMU is disabled
+	 */
+	asm volatile(
+		"   mtctr %2;\n"
+		"   mtmsr %3;\n"
+		"   isync;\n"
+		"0: dcbst   0, %0;\n"
+		"   addi    %0, %0, %4;\n"
+		"   bdnz    0b;\n"
+		"   sync;\n"
+		"   mtctr %2;\n"
+		"1: icbi    0, %1;\n"
+		"   addi    %1, %1, %4;\n"
+		"   bdnz    1b;\n"
+		"   sync;\n"
+		"   mtmsr %5;\n"
+		"   isync;\n"
+		: "+&r" (loop1), "+&r" (loop2)
+		: "r" (nb), "r" (msr), "i" (bytes), "r" (msr0)
+		: "ctr", "memory");
+}
+NOKPROBE_SYMBOL(flush_dcache_icache_phys)
+#else
+static void flush_dcache_icache_phys(unsigned long physaddr)
+{
+}
+#endif
+
+/**
+ * __flush_dcache_icache(): Flush a particular page from the data cache to RAM.
+ * Note: this is necessary because the instruction cache does *not*
+ * snoop from the data cache.
+ *
+ * @p: the address of the page to flush
+ */
+static void __flush_dcache_icache(void *p)
+{
+	unsigned long addr = (unsigned long)p & PAGE_MASK;
+
+	clean_dcache_range(addr, addr + PAGE_SIZE);
+
+	/*
+	 * We don't flush the icache on 44x. Those have a virtual icache and we
+	 * don't have access to the virtual address here (it's not the page
+	 * vaddr but where it's mapped in user space). The flushing of the
+	 * icache on these is handled elsewhere, when a change in the address
+	 * space occurs, before returning to user space.
+	 */
+
+	if (mmu_has_feature(MMU_FTR_TYPE_44x))
+		return;
+
+	invalidate_icache_range(addr, addr + PAGE_SIZE);
+}
+
+void flush_dcache_icache_folio(struct folio *folio)
+{
+	unsigned int i, nr = folio_nr_pages(folio);
+
+	if (flush_coherent_icache())
+		return;
+
+	if (!folio_test_highmem(folio)) {
+		void *addr = folio_address(folio);
+		for (i = 0; i < nr; i++)
+			__flush_dcache_icache(addr + i * PAGE_SIZE);
+	} else if (IS_ENABLED(CONFIG_BOOKE) || sizeof(phys_addr_t) > sizeof(void *)) {
+		for (i = 0; i < nr; i++) {
+			void *start = kmap_local_folio(folio, i * PAGE_SIZE);
+
+			__flush_dcache_icache(start);
+			kunmap_local(start);
+		}
+	} else {
+		unsigned long pfn = folio_pfn(folio);
+		for (i = 0; i < nr; i++)
+			flush_dcache_icache_phys((pfn + i) * PAGE_SIZE);
+	}
+}
+EXPORT_SYMBOL(flush_dcache_icache_folio);
+
+void clear_user_page(void *page, unsigned long vaddr, struct page *pg)
+{
+	clear_page(page);
+
+	/*
+	 * We shouldn't have to do this, but some versions of glibc
+	 * require it (ld.so assumes zero filled pages are icache clean)
+	 * - Anton
+	 */
+	flush_dcache_page(pg);
+}
+EXPORT_SYMBOL(clear_user_page);
+
+void copy_user_page(void *vto, void *vfrom, unsigned long vaddr,
+		    struct page *pg)
+{
+	copy_page(vto, vfrom);
+
+	/*
+	 * We should be able to use the following optimisation, however
+	 * there are two problems.
+	 * Firstly a bug in some versions of binutils meant PLT sections
+	 * were not marked executable.
+	 * Secondly the first word in the GOT section is blrl, used
+	 * to establish the GOT address. Until recently the GOT was
+	 * not marked executable.
+	 * - Anton
+	 */
+#if 0
+	if (!vma->vm_file && ((vma->vm_flags & VM_EXEC) == 0))
+		return;
+#endif
+
+	flush_dcache_page(pg);
+}
+
+void flush_icache_user_page(struct vm_area_struct *vma, struct page *page,
+			     unsigned long addr, int len)
+{
+	void *maddr;
+
+	maddr = kmap_local_page(page) + (addr & ~PAGE_MASK);
+	flush_icache_range((unsigned long)maddr, (unsigned long)maddr + len);
+	kunmap_local(maddr);
+}