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authorGuo Ren <guoren@linux.alibaba.com>2022-04-06 15:32:22 +0200
committerGuo Ren <guoren@linux.alibaba.com>2022-04-18 15:23:55 +0200
commit8318f7c231d5be09e47410c5ab387b9bef6fe19e (patch)
tree0072d121bd5f7b4d5615e72a34d0b6ebb9841a98 /arch
parentcsky: Add C based string functions (diff)
downloadlinux-8318f7c231d5be09e47410c5ab387b9bef6fe19e.tar.xz
linux-8318f7c231d5be09e47410c5ab387b9bef6fe19e.zip
csky: optimize memcpy_{from,to}io() and memset_io()
Optimize memcpy_{from,to}io() and memset_io() by transferring in 64 bit as much as possible with minimized barrier usage. This simplest optimization brings faster throughput compare to current byte-by-byte read and write with barrier in the loop. Code's skeleton is taken from the powerpc & arm64. Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Signed-off-by: Guo Ren <guoren@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/csky/include/asm/io.h11
-rw-r--r--arch/csky/kernel/Makefile2
-rw-r--r--arch/csky/kernel/io.c91
3 files changed, 103 insertions, 1 deletions
diff --git a/arch/csky/include/asm/io.h b/arch/csky/include/asm/io.h
index ed53f0b47388..4725bb977b0f 100644
--- a/arch/csky/include/asm/io.h
+++ b/arch/csky/include/asm/io.h
@@ -32,6 +32,17 @@
#endif
/*
+ * String version of I/O memory access operations.
+ */
+extern void __memcpy_fromio(void *, const volatile void __iomem *, size_t);
+extern void __memcpy_toio(volatile void __iomem *, const void *, size_t);
+extern void __memset_io(volatile void __iomem *, int, size_t);
+
+#define memset_io(c,v,l) __memset_io((c),(v),(l))
+#define memcpy_fromio(a,c,l) __memcpy_fromio((a),(c),(l))
+#define memcpy_toio(c,a,l) __memcpy_toio((c),(a),(l))
+
+/*
* I/O memory mapping functions.
*/
#define ioremap_wc(addr, size) \
diff --git a/arch/csky/kernel/Makefile b/arch/csky/kernel/Makefile
index 6c0f36010ed0..4eb41421ca5b 100644
--- a/arch/csky/kernel/Makefile
+++ b/arch/csky/kernel/Makefile
@@ -2,7 +2,7 @@
extra-y := head.o vmlinux.lds
obj-y += entry.o atomic.o signal.o traps.o irq.o time.o vdso.o vdso/
-obj-y += power.o syscall.o syscall_table.o setup.o
+obj-y += power.o syscall.o syscall_table.o setup.o io.o
obj-y += process.o cpu-probe.o ptrace.o stacktrace.o
obj-y += probes/
diff --git a/arch/csky/kernel/io.c b/arch/csky/kernel/io.c
new file mode 100644
index 000000000000..5883f13fa2b1
--- /dev/null
+++ b/arch/csky/kernel/io.c
@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <linux/types.h>
+#include <linux/io.h>
+
+/*
+ * Copy data from IO memory space to "real" memory space.
+ */
+void __memcpy_fromio(void *to, const volatile void __iomem *from, size_t count)
+{
+ while (count && !IS_ALIGNED((unsigned long)from, 4)) {
+ *(u8 *)to = __raw_readb(from);
+ from++;
+ to++;
+ count--;
+ }
+
+ while (count >= 4) {
+ *(u32 *)to = __raw_readl(from);
+ from += 4;
+ to += 4;
+ count -= 4;
+ }
+
+ while (count) {
+ *(u8 *)to = __raw_readb(from);
+ from++;
+ to++;
+ count--;
+ }
+}
+EXPORT_SYMBOL(__memcpy_fromio);
+
+/*
+ * Copy data from "real" memory space to IO memory space.
+ */
+void __memcpy_toio(volatile void __iomem *to, const void *from, size_t count)
+{
+ while (count && !IS_ALIGNED((unsigned long)to, 4)) {
+ __raw_writeb(*(u8 *)from, to);
+ from++;
+ to++;
+ count--;
+ }
+
+ while (count >= 4) {
+ __raw_writel(*(u32 *)from, to);
+ from += 4;
+ to += 4;
+ count -= 4;
+ }
+
+ while (count) {
+ __raw_writeb(*(u8 *)from, to);
+ from++;
+ to++;
+ count--;
+ }
+}
+EXPORT_SYMBOL(__memcpy_toio);
+
+/*
+ * "memset" on IO memory space.
+ */
+void __memset_io(volatile void __iomem *dst, int c, size_t count)
+{
+ u32 qc = (u8)c;
+
+ qc |= qc << 8;
+ qc |= qc << 16;
+
+ while (count && !IS_ALIGNED((unsigned long)dst, 4)) {
+ __raw_writeb(c, dst);
+ dst++;
+ count--;
+ }
+
+ while (count >= 4) {
+ __raw_writel(qc, dst);
+ dst += 4;
+ count -= 4;
+ }
+
+ while (count) {
+ __raw_writeb(c, dst);
+ dst++;
+ count--;
+ }
+}
+EXPORT_SYMBOL(__memset_io);