mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
From: Julian Vetter <julian@outer-limits.org>
To: Arnd Bergmann <arnd@arndb.de>,
	"James E . J . Bottomley" <James.Bottomley@HansenPartnership.com>,
	Helge Deller <deller@gmx.de>
Cc: linux-parisc@vger.kernel.org, linux-kernel@vger.kernel.org,
	Julian Vetter <julian@outer-limits.org>
Subject: [PATCH] parisc: Remove memcpy_fromio
Date: Thu, 30 Jan 2025 14:48:25 +0100	[thread overview]
Message-ID: <20250130134825.2646380-1-julian@outer-limits.org> (raw)

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@outer-limits.org>
---
 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


             reply	other threads:[~2025-01-30 13:48 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-01-30 13:48 Julian Vetter [this message]
2025-01-31  7:28 ` Arnd Bergmann
2025-02-03 10:21   ` Julian Vetter
2025-02-03 10:49     ` Arnd Bergmann
2025-02-03 18:39   ` Helge Deller

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20250130134825.2646380-1-julian@outer-limits.org \
    --to=julian@outer-limits.org \
    --cc=James.Bottomley@HansenPartnership.com \
    --cc=arnd@arndb.de \
    --cc=deller@gmx.de \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-parisc@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox

all inboxes | Powered by JetHome®