mtd: parsers: Add Qcom SMEM parser

NAND based Qualcomm platforms have the partition table populated in the
Shared Memory (SMEM). Hence, add a parser for parsing the partitions
from it.
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210104041137.113075-3-manivannan.sadhasivam@linaro.org

drivers/mtd/parsers/Kconfig

@@ -160,3 +160,11 @@ config MTD_REDBOOT_PARTS_READONLY
 	  'FIS directory' images, enable this option.
 
 endif # MTD_REDBOOT_PARTS
+
+config MTD_QCOMSMEM_PARTS
+	tristate "Qualcomm SMEM NAND flash partition parser"
+	depends on MTD_NAND_QCOM || COMPILE_TEST
+	depends on QCOM_SMEM
+	help
+	  This provides support for parsing partitions from Shared Memory (SMEM)
+	  for NAND flash on Qualcomm platforms.

drivers/mtd/parsers/Makefile

@@ -9,3 +9,4 @@ obj-$(CONFIG_MTD_AFS_PARTS)		+= afs.o
 obj-$(CONFIG_MTD_PARSER_TRX)		+= parser_trx.o
 obj-$(CONFIG_MTD_SHARPSL_PARTS)		+= sharpslpart.o
 obj-$(CONFIG_MTD_REDBOOT_PARTS)		+= redboot.o
+obj-$(CONFIG_MTD_QCOMSMEM_PARTS)	+= qcomsmempart.o

drivers/mtd/parsers/qcomsmempart.c

+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Qualcomm SMEM NAND flash partition parser
+ *
+ * Copyright (C) 2020, Linaro Ltd.
+ */
+
+#include <linux/ctype.h>
+#include <linux/module.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/slab.h>
+#include <linux/soc/qcom/smem.h>
+
+#define SMEM_AARM_PARTITION_TABLE	9
+#define SMEM_APPS			0
+
+#define SMEM_FLASH_PART_MAGIC1		0x55ee73aa
+#define SMEM_FLASH_PART_MAGIC2		0xe35ebddb
+#define SMEM_FLASH_PTABLE_V3		3
+#define SMEM_FLASH_PTABLE_V4		4
+#define SMEM_FLASH_PTABLE_MAX_PARTS_V3	16
+#define SMEM_FLASH_PTABLE_MAX_PARTS_V4	48
+#define SMEM_FLASH_PTABLE_HDR_LEN	(4 * sizeof(u32))
+#define SMEM_FLASH_PTABLE_NAME_SIZE	16
+
+/**
+ * struct smem_flash_pentry - SMEM Flash partition entry
+ * @name: Name of the partition
+ * @offset: Offset in blocks
+ * @length: Length of the partition in blocks
+ * @attr: Flags for this partition
+ */
+struct smem_flash_pentry {
+	char name[SMEM_FLASH_PTABLE_NAME_SIZE];
+	__le32 offset;
+	__le32 length;
+	u8 attr;
+} __packed __aligned(4);
+
+/**
+ * struct smem_flash_ptable - SMEM Flash partition table
+ * @magic1: Partition table Magic 1
+ * @magic2: Partition table Magic 2
+ * @version: Partition table version
+ * @numparts: Number of partitions in this ptable
+ * @pentry: Flash partition entries belonging to this ptable
+ */
+struct smem_flash_ptable {
+	__le32 magic1;
+	__le32 magic2;
+	__le32 version;
+	__le32 numparts;
+	struct smem_flash_pentry pentry[SMEM_FLASH_PTABLE_MAX_PARTS_V4];
+} __packed __aligned(4);
+
+static int parse_qcomsmem_part(struct mtd_info *mtd,
+			       const struct mtd_partition **pparts,
+			       struct mtd_part_parser_data *data)
+{
+	struct smem_flash_pentry *pentry;
+	struct smem_flash_ptable *ptable;
+	size_t len = SMEM_FLASH_PTABLE_HDR_LEN;
+	struct mtd_partition *parts;
+	int ret, i, numparts;
+	char *name, *c;
+
+	pr_debug("Parsing partition table info from SMEM\n");
+	ptable = qcom_smem_get(SMEM_APPS, SMEM_AARM_PARTITION_TABLE, &len);
+	if (IS_ERR(ptable)) {
+		pr_err("Error reading partition table header\n");
+		return PTR_ERR(ptable);
+	}
+
+	/* Verify ptable magic */
+	if (le32_to_cpu(ptable->magic1) != SMEM_FLASH_PART_MAGIC1 ||
+	    le32_to_cpu(ptable->magic2) != SMEM_FLASH_PART_MAGIC2) {
+		pr_err("Partition table magic verification failed\n");
+		return -EINVAL;
+	}
+
+	/* Ensure that # of partitions is less than the max we have allocated */
+	numparts = le32_to_cpu(ptable->numparts);
+	if (numparts > SMEM_FLASH_PTABLE_MAX_PARTS_V4) {
+		pr_err("Partition numbers exceed the max limit\n");
+		return -EINVAL;
+	}
+
+	/* Find out length of partition data based on table version */
+	if (le32_to_cpu(ptable->version) <= SMEM_FLASH_PTABLE_V3) {
+		len = SMEM_FLASH_PTABLE_HDR_LEN + SMEM_FLASH_PTABLE_MAX_PARTS_V3 *
+			sizeof(struct smem_flash_pentry);
+	} else if (le32_to_cpu(ptable->version) == SMEM_FLASH_PTABLE_V4) {
+		len = SMEM_FLASH_PTABLE_HDR_LEN + SMEM_FLASH_PTABLE_MAX_PARTS_V4 *
+			sizeof(struct smem_flash_pentry);
+	} else {
+		pr_err("Unknown ptable version (%d)", le32_to_cpu(ptable->version));
+		return -EINVAL;
+	}
+
+	/*
+	 * Now that the partition table header has been parsed, verified
+	 * and the length of the partition table calculated, read the
+	 * complete partition table
+	 */
+	ptable = qcom_smem_get(SMEM_APPS, SMEM_AARM_PARTITION_TABLE, &len);
+	if (IS_ERR_OR_NULL(ptable)) {
+		pr_err("Error reading partition table\n");
+		return PTR_ERR(ptable);
+	}
+
+	parts = kcalloc(numparts, sizeof(*parts), GFP_KERNEL);
+	if (!parts)
+		return -ENOMEM;
+
+	for (i = 0; i < numparts; i++) {
+		pentry = &ptable->pentry[i];
+		if (pentry->name[0] == '\0')
+			continue;
+
+		name = kstrdup(pentry->name, GFP_KERNEL);
+		if (!name) {
+			ret = -ENOMEM;
+			goto out_free_parts;
+		}
+
+		/* Convert name to lower case */
+		for (c = name; *c != '\0'; c++)
+			*c = tolower(*c);
+
+		parts[i].name = name;
+		parts[i].offset = le32_to_cpu(pentry->offset) * mtd->erasesize;
+		parts[i].mask_flags = pentry->attr;
+		parts[i].size = le32_to_cpu(pentry->length) * mtd->erasesize;
+		pr_debug("%d: %s offs=0x%08x size=0x%08x attr:0x%08x\n",
+			 i, pentry->name, le32_to_cpu(pentry->offset),
+			 le32_to_cpu(pentry->length), pentry->attr);
+	}
+
+	pr_debug("SMEM partition table found: ver: %d len: %d\n",
+		 le32_to_cpu(ptable->version), numparts);
+	*pparts = parts;
+
+	return numparts;
+
+out_free_parts:
+	while (--i >= 0)
+		kfree(parts[i].name);
+	kfree(parts);
+	*pparts = NULL;
+
+	return ret;
+}
+
+static const struct of_device_id qcomsmem_of_match_table[] = {
+	{ .compatible = "qcom,smem-part" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, qcomsmem_of_match_table);
+
+static struct mtd_part_parser mtd_parser_qcomsmem = {
+	.parse_fn = parse_qcomsmem_part,
+	.name = "qcomsmem",
+	.of_match_table = qcomsmem_of_match_table,
+};
+module_mtd_part_parser(mtd_parser_qcomsmem);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>");
+MODULE_DESCRIPTION("Qualcomm SMEM NAND flash partition parser");