Message-ID: <20150819163752.GZ13472@usrtlx11787.corpusers.net>
Date:	Wed, 19 Aug 2015 09:37:52 -0700
From:	Bjorn Andersson <bjorn.andersson@...ymobile.com>
To:	Mathieu Olivari <mathieu@...eaurora.org>
CC:	"robh+dt@...nel.org" <robh+dt@...nel.org>,
	"pawel.moll@....com" <pawel.moll@....com>,
	"mark.rutland@....com" <mark.rutland@....com>,
	"ijc+devicetree@...lion.org.uk" <ijc+devicetree@...lion.org.uk>,
	"galak@...eaurora.org" <galak@...eaurora.org>,
	"linux@....linux.org.uk" <linux@....linux.org.uk>,
	"dwmw2@...radead.org" <dwmw2@...radead.org>,
	"computersforpeace@...il.com" <computersforpeace@...il.com>,
	"agross@...eaurora.org" <agross@...eaurora.org>,
	"sboyd@...eaurora.org" <sboyd@...eaurora.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>
Subject: Re: [PATCH v4 3/3] mtd: add SMEM parser for QCOM platforms

On Tue 18 Aug 14:04 PDT 2015, Mathieu Olivari wrote:

> On QCOM platforms using MTD devices storage (such as IPQ806x), SMEM is
> used to store partition layout. This new parser can now be used to read
> SMEM and use it to register an MTD layout according to its content.
> 

Still looks good, but you should have added:

Acked-by: Bjorn Andersson <bjorn.andersson@...ymobile.com>

> Signed-off-by: Mathieu Olivari <mathieu@...eaurora.org>
> ---
> 
> Notes:
>     v2:
>     *Release the SPI device reference after looking it up (put_device())
>     *Represent SMEM data as __le32 rather than u32
>     *Move new DT nodes in their proper respective location
>     *Address readability concerns in MTD parser
>     
>     v3:
>     *Redefine SMEM functions prototypes for better readability
>     *Duplicate MTD name instead of pointing to SMEM string location in case
>      mtd layer tries to free it
>     *Rework some of the comments
>     
>     v4:
>     *Fix case in the license string
> 
>  drivers/mtd/Kconfig          |   7 ++
>  drivers/mtd/Makefile         |   1 +
>  drivers/mtd/qcom_smem_part.c | 246 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 254 insertions(+)
>  create mode 100644 drivers/mtd/qcom_smem_part.c
> 
> diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig
> index a03ad29..debc887 100644
> --- a/drivers/mtd/Kconfig
> +++ b/drivers/mtd/Kconfig
> @@ -155,6 +155,13 @@ config MTD_BCM47XX_PARTS
>  	  This provides partitions parser for devices based on BCM47xx
>  	  boards.
>  
> +config MTD_QCOM_SMEM_PARTS
> +	tristate "QCOM SMEM partitioning support"
> +	depends on QCOM_SMEM
> +	help
> +	  This provides partitions parser for QCOM devices using SMEM
> +	  such as IPQ806x.
> +
>  comment "User Modules And Translation Layers"
>  
>  #
> diff --git a/drivers/mtd/Makefile b/drivers/mtd/Makefile
> index 99bb9a1..b3c7de4 100644
> --- a/drivers/mtd/Makefile
> +++ b/drivers/mtd/Makefile
> @@ -13,6 +13,7 @@ obj-$(CONFIG_MTD_AFS_PARTS)	+= afs.o
>  obj-$(CONFIG_MTD_AR7_PARTS)	+= ar7part.o
>  obj-$(CONFIG_MTD_BCM63XX_PARTS)	+= bcm63xxpart.o
>  obj-$(CONFIG_MTD_BCM47XX_PARTS)	+= bcm47xxpart.o
> +obj-$(CONFIG_MTD_QCOM_SMEM_PARTS) += qcom_smem_part.o
>  
>  # 'Users' - code which presents functionality to userspace.
>  obj-$(CONFIG_MTD_BLKDEVS)	+= mtd_blkdevs.o
> diff --git a/drivers/mtd/qcom_smem_part.c b/drivers/mtd/qcom_smem_part.c
> new file mode 100644
> index 0000000..b4f8acc
> --- /dev/null
> +++ b/drivers/mtd/qcom_smem_part.c
> @@ -0,0 +1,246 @@
> +/*
> + * Copyright (c) 2015, The Linux Foundation. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 and
> + * only version 2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/device.h>
> +#include <linux/slab.h>
> +
> +#include <linux/mtd/mtd.h>
> +#include <linux/mtd/partitions.h>
> +#include <linux/spi/spi.h>
> +#include <linux/module.h>
> +
> +#include <linux/soc/qcom/smem.h>
> +
> +/* Processor/host identifier for the application processor */
> +#define QCOM_SMEM_GLOBAL		0
> +
> +/* SMEM items index */
> +#define SMEM_AARM_PARTITION_TABLE	9
> +#define SMEM_BOOT_FLASH_TYPE		421
> +#define SMEM_BOOT_FLASH_BLOCK_SIZE	424
> +
> +/* SMEM Flash types */
> +#define SMEM_FLASH_NAND			2
> +#define SMEM_FLASH_SPI			6
> +
> +#define SMEM_PART_NAME_SZ		16
> +#define SMEM_PARTS_MAX			32
> +
> +struct smem_partition {
> +	char name[SMEM_PART_NAME_SZ];
> +	__le32 start;
> +	__le32 size;
> +	__le32 attr;
> +};
> +
> +struct smem_partition_table {
> +	u8 magic[8];
> +	__le32 version;
> +	__le32 len;
> +	struct smem_partition parts[SMEM_PARTS_MAX];
> +};
> +
> +/* SMEM Magic values in partition table */
> +static const u8 SMEM_PTABLE_MAGIC[] = {
> +	0xaa, 0x73, 0xee, 0x55,
> +	0xdb, 0xbd, 0x5e, 0xe3,
> +};
> +
> +static int qcom_smem_get_flash_blksz(void)
> +{
> +	int ret;
> +	size_t size;
> +	u64 *smem_blksz;
> +
> +	ret = qcom_smem_get(QCOM_SMEM_GLOBAL, SMEM_BOOT_FLASH_BLOCK_SIZE,
> +			    (void **) &smem_blksz, &size);
> +
> +	if (ret < 0) {
> +		pr_err("Unable to read flash blksz from SMEM\n");
> +		return -ENOENT;
> +	}
> +
> +	if (size != sizeof(*smem_blksz)) {
> +		pr_err("Invalid flash blksz size in SMEM\n");
> +		return -EINVAL;
> +	}
> +
> +	/* Sanity check block size value before casting it */
> +	if (*smem_blksz > INT_MAX) {
> +		pr_err("Invalid flash block size in SMEM\n");
> +		return -EINVAL;
> +	}
> +
> +	return (int) *smem_blksz;
> +}
> +
> +static int qcom_smem_get_flash_type(void)
> +{
> +	int ret;
> +	size_t size;
> +	u64 *smem_flash_type;
> +
> +	ret = qcom_smem_get(QCOM_SMEM_GLOBAL, SMEM_BOOT_FLASH_TYPE,
> +			    (void **) &smem_flash_type, &size);
> +
> +	if (ret < 0) {
> +		pr_err("Unable to read flash type from SMEM\n");
> +		return -ENOENT;
> +	}
> +
> +	if (size != sizeof(*smem_flash_type)) {
> +		pr_err("Invalid flash type size in SMEM\n");
> +		return -EINVAL;
> +	}
> +
> +	/* Sanity check flash type value before casting it */
> +	if (*smem_flash_type > INT_MAX) {
> +		pr_err("Invalid flash type in SMEM\n");
> +		return -EINVAL;
> +	}
> +
> +	return (int) *smem_flash_type;
> +}
> +
> +static struct smem_partition *qcom_smem_get_flash_partitions(size_t *count)
> +{
> +	struct smem_partition_table *smem_parts;
> +	int ret;
> +
> +	ret = qcom_smem_get(QCOM_SMEM_GLOBAL, SMEM_AARM_PARTITION_TABLE,
> +			    (void **) &smem_parts, NULL);
> +
> +	if (ret < 0) {
> +		pr_err("Unable to read partition table from SMEM\n");
> +		return ERR_PTR(-ENOENT);
> +	}
> +
> +	if (memcmp(SMEM_PTABLE_MAGIC, smem_parts->magic,
> +		   sizeof(SMEM_PTABLE_MAGIC))) {
> +		pr_err("SMEM partition magic invalid\n");
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	if (le32_to_cpu(smem_parts->version) != 3) {
> +		pr_err("SMEM version unsupported\n");
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	*count = le32_to_cpu(smem_parts->len);
> +
> +	return smem_parts->parts;
> +}
> +
> +static int of_dev_node_match(struct device *dev, void *data)
> +{
> +	return dev->of_node == data;
> +}
> +
> +static bool is_spi_device(struct device_node *np)
> +{
> +	struct device *dev;
> +
> +	dev = bus_find_device(&spi_bus_type, NULL, np, of_dev_node_match);
> +	if (!dev)
> +		return false;
> +
> +	put_device(dev);
> +	return true;
> +}
> +
> +static int parse_qcom_smem_partitions(struct mtd_info *master,
> +				      struct mtd_partition **pparts,
> +				      struct mtd_part_parser_data *data)
> +{
> +	struct smem_partition *smem_part;
> +	int smem_flash_type, smem_blksz;
> +	size_t nbparts = 0, len;
> +	struct mtd_partition *mtd_parts;
> +	struct device_node *of_node = data->of_node;
> +
> +	/* Only parse partitions on the specified memory type */
> +	smem_flash_type = qcom_smem_get_flash_type();
> +	if (smem_flash_type < 0)
> +		return smem_flash_type;
> +
> +	if ((smem_flash_type == SMEM_FLASH_NAND && !mtd_type_is_nand(master))
> +	    || (smem_flash_type == SMEM_FLASH_SPI && !is_spi_device(of_node)))
> +		return 0;
> +
> +	/* Make sure the block size in SMEM matches the block size in MTD */
> +	smem_blksz = qcom_smem_get_flash_blksz();
> +	if (smem_blksz < 0)
> +		return smem_blksz;
> +
> +	if (smem_blksz != master->erasesize) {
> +		pr_err("SMEM block size differs from MTD block size\n");
> +		return -EINVAL;
> +	}
> +
> +	/* Get partition pointer from SMEM */
> +	smem_part = qcom_smem_get_flash_partitions(&nbparts);
> +	if (IS_ERR_OR_NULL(smem_part))
> +		return -EINVAL;
> +
> +	/* Allocate and populate the mtd structures */
> +	mtd_parts = kcalloc(nbparts, sizeof(*mtd_parts), GFP_KERNEL);
> +	if (!mtd_parts)
> +		return -ENOMEM;
> +
> +	*pparts = mtd_parts;
> +	len = nbparts;
> +
> +	while (len--) {
> +		mtd_parts->name = kstrdup(smem_part->name, GFP_KERNEL);
> +		mtd_parts->size = le32_to_cpu(smem_part->size) * smem_blksz;
> +		mtd_parts->offset = le32_to_cpu(smem_part->start) * smem_blksz;
> +
> +		/*
> +		 * The last SMEM partition may have its size marked as
> +		 * something like 0xffffffff, which means "until the end of the
> +		 * flash device". In this case, truncate it.
> +		 */
> +		if (mtd_parts->offset + mtd_parts->size > master->size)
> +			mtd_parts->size = master->size - mtd_parts->offset;
> +
> +		smem_part++;
> +		mtd_parts++;
> +	}
> +
> +	return nbparts;
> +}
> +
> +static struct mtd_part_parser qcom_smem_parser = {
> +	.owner = THIS_MODULE,
> +	.parse_fn = parse_qcom_smem_partitions,
> +	.name = "qcom-smem",
> +};
> +
> +static int __init qcom_smem_parser_init(void)
> +{
> +	register_mtd_parser(&qcom_smem_parser);
> +	return 0;
> +}
> +
> +static void __exit qcom_smem_parser_exit(void)
> +{
> +	deregister_mtd_parser(&qcom_smem_parser);
> +}
> +
> +module_init(qcom_smem_parser_init);
> +module_exit(qcom_smem_parser_exit);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("Mathieu Olivari <mathieu@...eaurora.org>");
> +MODULE_DESCRIPTION("Parsing code for SMEM based partition tables");
> -- 
> 2.1.4
> 
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