[PATCH] parisc: Remove memcpy_fromio

From: Julian Vetter
Date: Thu Jan 30 2025 - 08:51:19 EST


Fully migrate parisc to the IO functions from lib/iomem_copy.c. In a
recent patch the functions memset_io and memcpy_toio were removed, but
the memcpy_fromio was kept, because for very short sequences it does
half word accesses, whereas the functions in lib/iomem_copy.c do byte
accesses until the memory is naturally aligned and then do machine word
accesses. But I don't think the single half-word access merits keeping
the arch specific implementation, so, remove it as well.

Signed-off-by: Julian Vetter <julian@xxxxxxxxxxxxxxxx>
---
arch/parisc/include/asm/io.h | 3 --
arch/parisc/kernel/parisc_ksyms.c | 1 -
arch/parisc/lib/io.c | 61 -------------------------------
3 files changed, 65 deletions(-)

diff --git a/arch/parisc/include/asm/io.h b/arch/parisc/include/asm/io.h
index 3143cf29ce27..61173a2b38e4 100644
--- a/arch/parisc/include/asm/io.h
+++ b/arch/parisc/include/asm/io.h
@@ -135,9 +135,6 @@ static inline void gsc_writeq(unsigned long long val, unsigned long addr)

#define pci_iounmap pci_iounmap

-void memcpy_fromio(void *dst, const volatile void __iomem *src, int count);
-#define memcpy_fromio memcpy_fromio
-
/* Port-space IO */

#define inb_p inb
diff --git a/arch/parisc/kernel/parisc_ksyms.c b/arch/parisc/kernel/parisc_ksyms.c
index 1c366b0d3134..509146a52725 100644
--- a/arch/parisc/kernel/parisc_ksyms.c
+++ b/arch/parisc/kernel/parisc_ksyms.c
@@ -43,7 +43,6 @@ EXPORT_SYMBOL($global$);
#endif

#include <asm/io.h>
-EXPORT_SYMBOL(memcpy_fromio);

extern void $$divI(void);
extern void $$divU(void);
diff --git a/arch/parisc/lib/io.c b/arch/parisc/lib/io.c
index 6e81200dc87a..3c7e617f5a93 100644
--- a/arch/parisc/lib/io.c
+++ b/arch/parisc/lib/io.c
@@ -12,67 +12,6 @@
#include <linux/module.h>
#include <asm/io.h>

-/*
-** Copies a block of memory from a device in an efficient manner.
-** Assumes the device can cope with 32-bit transfers. If it can't,
-** don't use this function.
-**
-** CR16 counts on C3000 reading 256 bytes from Symbios 896 RAM:
-** 27341/64 = 427 cyc per int
-** 61311/128 = 478 cyc per short
-** 122637/256 = 479 cyc per byte
-** Ergo bus latencies dominant (not transfer size).
-** Minimize total number of transfers at cost of CPU cycles.
-** TODO: only look at src alignment and adjust the stores to dest.
-*/
-void memcpy_fromio(void *dst, const volatile void __iomem *src, int count)
-{
- /* first compare alignment of src/dst */
- if ( (((unsigned long)dst ^ (unsigned long)src) & 1) || (count < 2) )
- goto bytecopy;
-
- if ( (((unsigned long)dst ^ (unsigned long)src) & 2) || (count < 4) )
- goto shortcopy;
-
- /* Then check for misaligned start address */
- if ((unsigned long)src & 1) {
- *(u8 *)dst = readb(src);
- src++;
- dst++;
- count--;
- if (count < 2) goto bytecopy;
- }
-
- if ((unsigned long)src & 2) {
- *(u16 *)dst = __raw_readw(src);
- src += 2;
- dst += 2;
- count -= 2;
- }
-
- while (count > 3) {
- *(u32 *)dst = __raw_readl(src);
- dst += 4;
- src += 4;
- count -= 4;
- }
-
- shortcopy:
- while (count > 1) {
- *(u16 *)dst = __raw_readw(src);
- src += 2;
- dst += 2;
- count -= 2;
- }
-
- bytecopy:
- while (count--) {
- *(char *)dst = readb(src);
- src++;
- dst++;
- }
-}
-
/*
* Read COUNT 8-bit bytes from port PORT into memory starting at
* SRC.
--
2.34.1