[PATCH 1/4] Consolidate __memcpy_{to,from}io and __memset_io into a single lib

[Julian Vetter]

Various architectures have almost the same implementations for
__memcpy_{to,from}io and __memset_io functions. So, consolidate them and
introduce a CONFIG_GENERIC_IO flag to build the given lib/io.c.

Reviewed-by: Yann Sionneau <ysionneau at kalrayinc.com>
Signed-off-by: Julian Vetter <jvetter at kalrayinc.com>
---
 lib/Kconfig  |   3 ++
 lib/Makefile |   2 +
 lib/io.c     | 101 +++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 106 insertions(+)
 create mode 100644 lib/io.c

diff --git a/lib/Kconfig b/lib/Kconfig
index b38849af6f13..2ebdc41cf0a1 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -765,6 +765,9 @@ config GENERIC_LIB_UCMPDI2
 config GENERIC_LIB_DEVMEM_IS_ALLOWED
 	bool
 
+config GENERIC_IO
+	bool
+
 config PLDMFW
 	bool
 	default n
diff --git a/lib/Makefile b/lib/Makefile
index 322bb127b4dc..d231a1c49715 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -135,6 +135,8 @@ obj-$(CONFIG_HAS_IOMEM) += iomap_copy.o devres.o
 obj-$(CONFIG_CHECK_SIGNATURE) += check_signature.o
 obj-$(CONFIG_DEBUG_LOCKING_API_SELFTESTS) += locking-selftest.o
 
+obj-$(CONFIG_GENERIC_IO) += io.o
+
 lib-y += logic_pio.o
 
 lib-$(CONFIG_INDIRECT_IOMEM) += logic_iomem.o
diff --git a/lib/io.c b/lib/io.c
new file mode 100644
index 000000000000..c3385566a3e1
--- /dev/null
+++ b/lib/io.c
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * derived from arch/arm/kernel/io.c
+ *
+ * Copyright (C) 2024 Kalray Inc.
+ * Author(s): Julian Vetter
+ */
+
+#include <linux/export.h>
+#include <linux/types.h>
+#include <linux/io.h>
+
+#define NATIVE_STORE_SIZE	(BITS_PER_LONG/8)
+
+#if IS_ENABLED(CONFIG_64BIT)
+#define __raw_write_native(val, dst) __raw_writeq(val, dst)
+#define __raw_read_native(src) __raw_readq((src))
+#else
+#define __raw_write_native(val, dst) __raw_writel(val, dst)
+#define __raw_read_native(src) __raw_readl(src)
+#endif
+
+void __memcpy_fromio(void *to, const volatile void __iomem *from, size_t count)
+{
+	while (count && !IS_ALIGNED((unsigned long)from, NATIVE_STORE_SIZE)) {
+		*(u8 *)to = __raw_readb(from);
+		from++;
+		to++;
+		count--;
+	}
+
+	while (count >= NATIVE_STORE_SIZE) {
+		*(uintptr_t *)to = __raw_read_native(from);
+		from += NATIVE_STORE_SIZE;
+		to += NATIVE_STORE_SIZE;
+		count -= NATIVE_STORE_SIZE;
+	}
+
+	while (count) {
+		*(u8 *)to = __raw_readb(from);
+		from++;
+		to++;
+		count--;
+	}
+}
+EXPORT_SYMBOL(__memcpy_fromio);
+
+void __memcpy_toio(volatile void __iomem *to, const void *from, size_t count)
+{
+	while (count && !IS_ALIGNED((unsigned long)to, NATIVE_STORE_SIZE)) {
+		__raw_writeb(*(u8 *)from, to);
+		from++;
+		to++;
+		count--;
+	}
+
+	while (count >= NATIVE_STORE_SIZE) {
+		__raw_write_native(*(uintptr_t *)from, to);
+		from += NATIVE_STORE_SIZE;
+		to += NATIVE_STORE_SIZE;
+		count -= NATIVE_STORE_SIZE;
+	}
+
+	while (count) {
+		__raw_writeb(*(u8 *)from, to);
+		from++;
+		to++;
+		count--;
+	}
+}
+EXPORT_SYMBOL(__memcpy_toio);
+
+void __memset_io(volatile void __iomem *dst, int c, size_t count)
+{
+	uintptr_t qc = (u8)c;
+
+	qc |= qc << 8;
+	qc |= qc << 16;
+#if IS_ENABLED(CONFIG_64BIT)
+	qc |= qc << 32;
+#endif
+
+	while (count && !IS_ALIGNED((unsigned long)dst, NATIVE_STORE_SIZE)) {
+		__raw_writeb(c, dst);
+		dst++;
+		count--;
+	}
+
+	while (count >= NATIVE_STORE_SIZE) {
+		__raw_write_native(qc, dst);
+		dst += NATIVE_STORE_SIZE;
+		count -= NATIVE_STORE_SIZE;
+	}
+
+	while (count) {
+		__raw_writeb(c, dst);
+		dst++;
+		count--;
+	}
+}
+EXPORT_SYMBOL(__memset_io);
-- 
2.34.1