path: root/drivers/misc/genwqe/card_utils.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * IBM Accelerator Family 'GenWQE'
 *
 * (C) Copyright IBM Corp. 2013
 *
 * Author: Frank Haverkamp <haver@linux.vnet.ibm.com>
 * Author: Joerg-Stephan Vogt <jsvogt@de.ibm.com>
 * Author: Michael Jung <mijung@gmx.net>
 * Author: Michael Ruettger <michael@ibmra.de>
 */

/*
 * Miscelanous functionality used in the other GenWQE driver parts.
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/vmalloc.h>
#include <linux/page-flags.h>
#include <linux/scatterlist.h>
#include <linux/hugetlb.h>
#include <linux/iommu.h>
#include <linux/pci.h>
#include <linux/dma-mapping.h>
#include <linux/ctype.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/pgtable.h>

#include "genwqe_driver.h"
#include "card_base.h"
#include "card_ddcb.h"

/**
 * __genwqe_writeq() - Write 64-bit register
 * @cd:	        genwqe device descriptor
 * @byte_offs:  byte offset within BAR
 * @val:        64-bit value
 *
 * Return: 0 if success; < 0 if error
 */
int __genwqe_writeq(struct genwqe_dev *cd, u64 byte_offs, u64 val)
{
	struct pci_dev *pci_dev = cd->pci_dev;

	if (cd->err_inject & GENWQE_INJECT_HARDWARE_FAILURE)
		return -EIO;

	if (cd->mmio == NULL)
		return -EIO;

	if (pci_channel_offline(pci_dev))
		return -EIO;

	__raw_writeq((__force u64)cpu_to_be64(val), cd->mmio + byte_offs);
	return 0;
}

/**
 * __genwqe_readq() - Read 64-bit register
 * @cd:         genwqe device descriptor
 * @byte_offs:  offset within BAR
 *
 * Return: value from register
 */
u64 __genwqe_readq(struct genwqe_dev *cd, u64 byte_offs)
{
	if (cd->err_inject & GENWQE_INJECT_HARDWARE_FAILURE)
		return 0xffffffffffffffffull;

	if ((cd->err_inject & GENWQE_INJECT_GFIR_FATAL) &&
	    (byte_offs == IO_SLC_CFGREG_GFIR))
		return 0x000000000000ffffull;

	if ((cd->err_inject & GENWQE_INJECT_GFIR_INFO) &&
	    (byte_offs == IO_SLC_CFGREG_GFIR))
		return 0x00000000ffff0000ull;

	if (cd->mmio == NULL)
		return 0xffffffffffffffffull;

	return be64_to_cpu((__force __be64)__raw_readq(cd->mmio + byte_offs));
}

/**
 * __genwqe_writel() - Write 32-bit register
 * @cd:	        genwqe device descriptor
 * @byte_offs:  byte offset within BAR
 * @val:        32-bit value
 *
 * Return: 0 if success; < 0 if error
 */
int __genwqe_writel(struct genwqe_dev *cd, u64 byte_offs, u32 val)
{
	struct pci_dev *pci_dev = cd->pci_dev;

	if (cd->err_inject & GENWQE_INJECT_HARDWARE_FAILURE)
		return -EIO;

	if (cd->mmio == NULL)
		return -EIO;

	if (pci_channel_offline(pci_dev))
		return -EIO;

	__raw_writel((__force u32)cpu_to_be32(val), cd->mmio + byte_offs);
	return 0;
}

/**
 * __genwqe_readl() - Read 32-bit register
 * @cd:         genwqe device descriptor
 * @byte_offs:  offset within BAR
 *
 * Return: Value from register
 */
u32 __genwqe_readl(struct genwqe_dev *cd, u64 byte_offs)
{
	if (cd->err_inject & GENWQE_INJECT_HARDWARE_FAILURE)
		return 0xffffffff;

	if (cd->mmio == NULL)
		return 0xffffffff;

	return be32_to_cpu((__force __be32)__raw_readl(cd->mmio + byte_offs));
}

/**
 * genwqe_read_app_id() - Extract app_id
 * @cd:	        genwqe device descriptor
 * @app_name:   carrier used to pass-back name
 * @len:        length of data for name
 *
 * app_unitcfg need to be filled with valid data first
 */
int genwqe_read_app_id(struct genwqe_dev *cd, char *app_name, int len)
{
	int i, j;
	u32 app_id = (u32)cd->app_unitcfg;

	memset(app_name, 0, len);
	for (i = 0, j = 0; j < min(len, 4); j++) {
		char ch = (char)((app_id >> (24 - j*8)) & 0xff);

		if (ch == ' ')
			continue;
		app_name[i++] = isprint(ch) ? ch : 'X';
	}
	return i;
}

/**
 * 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
 * @init:       initial crc (0xffffffff at start)
 *
 * polynomial = x^32 * + x^29 + x^18 + x^14 + x^3 + 1 (0x20044009)
 *
 * Example: 4 bytes 0x01 0x02 0x03 0x04 with init=0xffffffff should
 * result in a crc32 of 0xf33cb7d3.
 *
 * The existing kernel crc functions did not cover this polynom yet.
 *
 * Return: crc32 checksum.
 */
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;
}</