crypto: omap - add base support library for common routines

This contains the generic APIs for aligning SG buffers.
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/Kconfig

@@ -314,6 +314,15 @@ config HW_RANDOM_PPC4XX
 	 This option provides the kernel-side support for the TRNG hardware
 	 found in the security function of some PowerPC 4xx SoCs.
 
+config CRYPTO_DEV_OMAP
+	tristate "Support for OMAP crypto HW accelerators"
+	depends on ARCH_OMAP2PLUS
+	help
+	  OMAP processors have various crypto HW accelerators. Select this if
+          you want to use the OMAP modules for any of the crypto algorithms.
+
+if CRYPTO_DEV_OMAP
+
 config CRYPTO_DEV_OMAP_SHAM
 	tristate "Support for OMAP MD5/SHA1/SHA2 hw accelerator"
 	depends on ARCH_OMAP2PLUS
@@ -351,6 +360,8 @@ config CRYPTO_DEV_OMAP_DES
 	  the ECB and CBC modes of operation are supported by the driver. Also
 	  accesses made on unaligned boundaries are supported.
 
+endif # CRYPTO_DEV_OMAP
+
 config CRYPTO_DEV_PICOXCELL
 	tristate "Support for picoXcell IPSEC and Layer2 crypto engines"
 	depends on (ARCH_PICOXCELL || COMPILE_TEST) && HAVE_CLK

drivers/crypto/Makefile

@@ -20,6 +20,7 @@ obj-$(CONFIG_CRYPTO_DEV_MXC_SCC) += mxc-scc.o
 obj-$(CONFIG_CRYPTO_DEV_NIAGARA2) += n2_crypto.o
 n2_crypto-y := n2_core.o n2_asm.o
 obj-$(CONFIG_CRYPTO_DEV_NX) += nx/
+obj-$(CONFIG_CRYPTO_DEV_OMAP) += omap-crypto.o
 obj-$(CONFIG_CRYPTO_DEV_OMAP_AES) += omap-aes.o
 obj-$(CONFIG_CRYPTO_DEV_OMAP_DES) += omap-des.o
 obj-$(CONFIG_CRYPTO_DEV_OMAP_SHAM) += omap-sham.o

drivers/crypto/omap-crypto.c

+/*
+ * OMAP Crypto driver common support routines.
+ *
+ * Copyright (c) 2017 Texas Instruments Incorporated
+ *   Tero Kristo <t-kristo@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/scatterlist.h>
+#include <crypto/scatterwalk.h>
+
+#include "omap-crypto.h"
+
+static int omap_crypto_copy_sg_lists(int total, int bs,
+				     struct scatterlist **sg,
+				     struct scatterlist *new_sg, u16 flags)
+{
+	int n = sg_nents(*sg);
+	struct scatterlist *tmp;
+
+	if (!(flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY)) {
+		new_sg = kmalloc_array(n, sizeof(*sg), GFP_KERNEL);
+		if (!new_sg)
+			return -ENOMEM;
+
+		sg_init_table(new_sg, n);
+	}
+
+	tmp = new_sg;
+
+	while (*sg && total) {
+		int len = (*sg)->length;
+
+		if (total < len)
+			len = total;
+
+		if (len > 0) {
+			total -= len;
+			sg_set_page(tmp, sg_page(*sg), len, (*sg)->offset);
+			if (total <= 0)
+				sg_mark_end(tmp);
+			tmp = sg_next(tmp);
+		}
+
+		*sg = sg_next(*sg);
+	}
+
+	*sg = new_sg;
+
+	return 0;
+}
+
+static int omap_crypto_copy_sgs(int total, int bs, struct scatterlist **sg,
+				struct scatterlist *new_sg, u16 flags)
+{
+	void *buf;
+	int pages;
+	int new_len;
+
+	new_len = ALIGN(total, bs);
+	pages = get_order(new_len);
+
+	buf = (void *)__get_free_pages(GFP_ATOMIC, pages);
+	if (!buf) {
+		pr_err("%s: Couldn't allocate pages for unaligned cases.\n",
+		       __func__);
+		return -ENOMEM;
+	}
+
+	if (flags & OMAP_CRYPTO_COPY_DATA) {
+		scatterwalk_map_and_copy(buf, *sg, 0, total, 0);
+		if (flags & OMAP_CRYPTO_ZERO_BUF)
+			memset(buf + total, 0, new_len - total);
+	}
+
+	if (!(flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY))
+		sg_init_table(new_sg, 1);
+
+	sg_set_buf(new_sg, buf, new_len);
+
+	*sg = new_sg;
+
+	return 0;
+}
+
+static int omap_crypto_check_sg(struct scatterlist *sg, int total, int bs,
+				u16 flags)
+{
+	int len = 0;
+	int num_sg = 0;
+
+	if (!IS_ALIGNED(total, bs))
+		return OMAP_CRYPTO_NOT_ALIGNED;
+
+	while (sg) {
+		num_sg++;
+
+		if (!IS_ALIGNED(sg->offset, 4))
+			return OMAP_CRYPTO_NOT_ALIGNED;
+		if (!IS_ALIGNED(sg->length, bs))
+			return OMAP_CRYPTO_NOT_ALIGNED;
+
+		len += sg->length;
+		sg = sg_next(sg);
+
+		if (len >= total)
+			break;
+	}
+
+	if ((flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY) && num_sg > 1)
+		return OMAP_CRYPTO_NOT_ALIGNED;
+
+	if (len != total)
+		return OMAP_CRYPTO_BAD_DATA_LENGTH;
+
+	return 0;
+}
+
+int omap_crypto_align_sg(struct scatterlist **sg, int total, int bs,
+			 struct scatterlist *new_sg, u16 flags,
+			 u8 flags_shift, unsigned long *dd_flags)
+{
+	int ret;
+
+	*dd_flags &= ~(OMAP_CRYPTO_COPY_MASK << flags_shift);
+
+	if (flags & OMAP_CRYPTO_FORCE_COPY)
+		ret = OMAP_CRYPTO_NOT_ALIGNED;
+	else
+		ret = omap_crypto_check_sg(*sg, total, bs, flags);
+
+	if (ret == OMAP_CRYPTO_NOT_ALIGNED) {
+		ret = omap_crypto_copy_sgs(total, bs, sg, new_sg, flags);
+		if (ret)
+			return ret;
+		*dd_flags |= OMAP_CRYPTO_DATA_COPIED << flags_shift;
+	} else if (ret == OMAP_CRYPTO_BAD_DATA_LENGTH) {
+		ret = omap_crypto_copy_sg_lists(total, bs, sg, new_sg, flags);
+		if (ret)
+			return ret;
+		if (!(flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY))
+			*dd_flags |= OMAP_CRYPTO_SG_COPIED << flags_shift;
+	} else if (flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY) {
+		sg_set_buf(new_sg, sg_virt(*sg), (*sg)->length);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(omap_crypto_align_sg);
+
+void omap_crypto_cleanup(struct scatterlist *sg, struct scatterlist *orig,
+			 int offset, int len, u8 flags_shift,
+			 unsigned long flags)
+{
+	void *buf;
+	int pages;
+
+	flags >>= flags_shift;
+	flags &= OMAP_CRYPTO_COPY_MASK;
+
+	if (!flags)
+		return;
+
+	buf = sg_virt(sg);
+	pages = get_order(len);
+
+	if (orig && (flags & OMAP_CRYPTO_COPY_MASK))
+		scatterwalk_map_and_copy(buf, orig, offset, len, 1);
+
+	if (flags & OMAP_CRYPTO_DATA_COPIED)
+		free_pages((unsigned long)buf, pages);
+	else if (flags & OMAP_CRYPTO_SG_COPIED)
+		kfree(sg);
+}
+EXPORT_SYMBOL_GPL(omap_crypto_cleanup);
+
+MODULE_DESCRIPTION("OMAP crypto support library.");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Tero Kristo <t-kristo@ti.com>");

drivers/crypto/omap-crypto.h

+/*
+ * OMAP Crypto driver common support routines.
+ *
+ * Copyright (c) 2017 Texas Instruments Incorporated
+ *   Tero Kristo <t-kristo@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#ifndef __CRYPTO_OMAP_CRYPTO_H
+#define __CRYPTO_OMAP_CRYPTO_H
+
+enum {
+	OMAP_CRYPTO_NOT_ALIGNED = 1,
+	OMAP_CRYPTO_BAD_DATA_LENGTH,
+};
+
+#define OMAP_CRYPTO_DATA_COPIED		BIT(0)
+#define OMAP_CRYPTO_SG_COPIED		BIT(1)
+
+#define OMAP_CRYPTO_COPY_MASK		0x3
+
+#define OMAP_CRYPTO_COPY_DATA		BIT(0)
+#define OMAP_CRYPTO_FORCE_COPY		BIT(1)
+#define OMAP_CRYPTO_ZERO_BUF		BIT(2)
+#define OMAP_CRYPTO_FORCE_SINGLE_ENTRY	BIT(3)
+
+int omap_crypto_align_sg(struct scatterlist **sg, int total, int bs,
+			 struct scatterlist *new_sg, u16 flags,
+			 u8 flags_shift, unsigned long *dd_flags);
+void omap_crypto_cleanup(struct scatterlist *sg, struct scatterlist *orig,
+			 int offset, int len, u8 flags_shift,
+			 unsigned long flags);
+
+#endif