linux-kernel - [RFC 2/2] GenWQE: Make use of the generic CRC kernel infrastructure

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Message-Id: <1386780563-1722-2-git-send-email-haver@linux.vnet.ibm.com>
Date:	Wed, 11 Dec 2013 17:49:23 +0100
From:	Frank Haverkamp <haver@...ux.vnet.ibm.com>
To:	linux-kernel@...r.kernel.org
Cc:	arnd@...db.de, gregkh@...uxfoundation.org, cody@...ux.vnet.ibm.com,
	schwidefsky@...ibm.com, utz.bacher@...ibm.com, mmarek@...e.cz,
	rmallon@...il.com, jsvogt@...ibm.com, MIJUNG@...ibm.com,
	cascardo@...ux.vnet.ibm.com, michael@...ra.de,
	haver@...ux.vnet.ibm.com
Subject: [RFC 2/2] GenWQE: Make use of the generic CRC kernel infrastructure

Instead of reimplementing the CRC, make use of the generic CRC kernel
infrastructure. Note that GenWQE seems currently the only one using
this particular polynomial.

This change requires a previous patch which adds the GenWQE crc32 to
the generic kernel crc32 support.

Signed-off-by: Frank Haverkamp <haver@...ux.vnet.ibm.com>
---
 drivers/misc/genwqe/card_base.c  |    2 	0 +	2 -	0 !
 drivers/misc/genwqe/card_base.h  |    1 	0 +	1 -	0 !
 drivers/misc/genwqe/card_utils.c |   39 	2 +	37 -	0 !
 3 files changed, 2 insertions(+), 40 deletions(-)

--- a/drivers/misc/genwqe/card_base.c
+++ b/drivers/misc/genwqe/card_base.c
@@ -1016,8 +1016,6 @@ static int genwqe_probe(struct pci_dev *
 	int err;
 	struct genwqe_dev *cd;
 
-	genwqe_init_crc32();
-
 	cd = genwqe_dev_alloc();
 	if (IS_ERR(cd)) {
 		dev_err(&pci_dev->dev, "err: could not alloc mem (err=%d)!\n",
--- a/drivers/misc/genwqe/card_base.h
+++ b/drivers/misc/genwqe/card_base.h
@@ -441,7 +441,6 @@ int  genwqe_ffdc_dump_dma(struct genwqe_
 int  genwqe_init_debug_data(struct genwqe_dev *cd,
 			    struct genwqe_debug_data *d);
 
-void genwqe_init_crc32(void);
 int  genwqe_read_app_id(struct genwqe_dev *cd, char *app_name, int len);
 
 /* Memory allocation/deallocation; dma address handling */
--- a/drivers/misc/genwqe/card_utils.c
+++ b/drivers/misc/genwqe/card_utils.c
@@ -37,6 +37,7 @@
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/delay.h>
+#include <linux/crc32.h>
 #include <asm/pgtable.h>
 
 #include "genwqe_driver.h"
@@ -151,34 +152,6 @@ int genwqe_read_app_id(struct genwqe_dev
 }
 
 /**
- * genwqe_init_crc32() - Prepare a lookup table for fast crc32 calculations
- *
- * Existing kernel functions seem to use a different polynom,
- * therefore we could not use them here.
- *
- * Genwqe's Polynomial = 0x20044009
- */
-#define CRC32_POLYNOMIAL	0x20044009
-static u32 crc32_tab[256];	/* crc32 lookup table */
-
-void genwqe_init_crc32(void)
-{
-	int i, j;
-	u32 crc;
-
-	for (i = 0;  i < 256;  i++) {
-		crc = i << 24;
-		for (j = 0;  j < 8;  j++) {
-			if (crc & 0x80000000)
-				crc = (crc << 1) ^ CRC32_POLYNOMIAL;
-			else
-				crc = (crc << 1);
-		}
-		crc32_tab[i] = crc;
-	}
-}
-
-/**
  * genwqe_crc32() - Generate 32-bit crc as required for DDCBs
  * @buff:       pointer to data buffer
  * @len:        length of data for calculation
@@ -195,15 +168,7 @@ void genwqe_init_crc32(void)
  */
 u32 genwqe_crc32(u8 *buff, size_t len, u32 init)
 {
-	int i;
-	u32 crc;
-
-	crc = init;
-	while (len--) {
-		i = ((crc >> 24) ^ *buff++) & 0xFF;
-		crc = (crc << 8) ^ crc32_tab[i];
-	}
-	return crc;
+	return __crc32g_be(init, buff, len);
 }
 
 void *__genwqe_alloc_consistent(struct genwqe_dev *cd, size_t size,

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