[3/3] mtd: add SMEM parser for QCOM platforms

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.

Signed-off-by: Mathieu Olivari <mathieu@codeaurora.org>
---
 drivers/mtd/Kconfig          |   7 ++
 drivers/mtd/Makefile         |   1 +
 drivers/mtd/qcom_smem_part.c | 224 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 232 insertions(+)
 create mode 100644 drivers/mtd/qcom_smem_part.c

On 08/13/2015 02:33 PM, Mathieu Olivari wrote:
> diff --git a/drivers/mtd/qcom_smem_part.c b/drivers/mtd/qcom_smem_part.c
> new file mode 100644
> index 0000000..6cbf610
> --- /dev/null
> +++ b/drivers/mtd/qcom_smem_part.c
>
> +#define SMEM_PARTS_MAX			32
> +
> +struct smem_partition {
> +	char name[SMEM_PART_NAME_SZ];
> +	uint32_t start;
> +	uint32_t size;
> +	uint32_t attr;

Is this little endian? __le32? I think so.

> +};
> +
> +struct smem_partition_table {
> +	uint32_t magic[2];
> +	uint32_t version;
> +	uint32_t len;

Same for these being little endian. And if so, please make magic into a 
byte array of size 8 and then do a memcmp with another static byte array.

> +	struct smem_partition parts[SMEM_PARTS_MAX];
> +};
> +
> +static int qcom_smem_get_flash_blksz(uint64_t **smem_blksz)

I don't know, but I prefer u64 because it's short and sweet. But I'm not 
the maintainer here.

> +{
> +	int ret;
> +	size_t size;
> +
> +	ret = qcom_smem_get(SMEM_HOST_APPS, SMEM_BOOT_FLASH_BLOCK_SIZE,
> +			    (void **) smem_blksz, &size);

Is the cast necessary?

> +
> +	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;
> +	}
> +
> +	return 0;
> +}
> +
> +static int qcom_smem_get_flash_type(uint64_t **smem_flash_type)
> +{
> +	int ret;
> +	size_t size;
> +
> +	ret = qcom_smem_get(SMEM_HOST_APPS, 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;
> +	}
> +
> +	return 0;
> +}
> +
> +static int qcom_smem_get_flash_partitions(struct smem_partition_table **pparts)
> +{
> +	int ret;
> +	size_t size;
> +
> +	ret = qcom_smem_get(SMEM_HOST_APPS, SMEM_AARM_PARTITION_TABLE,
> +			    (void **) pparts, &size);
> +
> +	if (ret < 0) {
> +		pr_err("Unable to read partition table from SMEM\n");
> +		return -ENOENT;
> +	}
> +
> +	return 0;
> +}
> +
> +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);

I'm pretty sure this holds a reference to the device that needs to be 
released with put_device().

> +	return dev ? true : false;
> +}
> +
> +static int parse_qcom_smem_partitions(struct mtd_info *master,
> +				      struct mtd_partition **pparts,
> +				      struct mtd_part_parser_data *data)
> +{
> +	struct smem_partition_table *smem_parts;
> +	uint64_t *smem_flash_type, *smem_blksz;
> +	struct mtd_partition *mtd_parts;
> +	struct device_node *of_node = data->of_node;
> +	int i, ret;
> +
> +	/*
> +	 * SMEM will only store the partition table of the boot device.
> +	 * If this is not the boot device, do not return any partition.
> +	 */
> +	ret = qcom_smem_get_flash_type(&smem_flash_type);
> +	if (ret < 0)
> +		return ret;
> +
> +	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;
> +
> +	/*
> +	 * Just for sanity purpose, make sure the block size in SMEM matches the
> +	 * block size of the MTD device
> +	 */
> +	ret = qcom_smem_get_flash_blksz(&smem_blksz);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (*smem_blksz != master->erasesize) {
> +		pr_err("SMEM block size differs from MTD block size\n");
> +		return -EINVAL;
> +	}
> +
> +	/* Get partition pointer from SMEM */
> +	ret = qcom_smem_get_flash_partitions(&smem_parts);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (smem_parts->magic[0] != SMEM_PTABLE_MAGIC_1 ||
> +	    smem_parts->magic[1] != SMEM_PTABLE_MAGIC_2) {
> +		pr_err("SMEM partition magic invalid\n");
> +		return -EINVAL;
> +	}
> +
> +	/* Allocate and populate the mtd structures */
> +	mtd_parts = kcalloc(smem_parts->len, sizeof(struct mtd_partition),

sizeof(*mtd_parts)?

> +			    GFP_KERNEL);
> +	if (mtd_parts == NULL)

if (!mtd_parts) is more kernel style.

> +		return -ENOMEM;
> +
> +	for (i = 0; i < smem_parts->len; i++) {
> +		struct smem_partition *part = &smem_parts->parts[i];
> +
> +		mtd_parts[i].name = part->name;
> +		mtd_parts[i].size = part->size * (*smem_blksz);
> +		mtd_parts[i].offset = 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[i].offset + mtd_parts[i].size > master->size)
> +			mtd_parts[i].size = master->size - mtd_parts[i].offset;

That is 7 mtd_parts[i]. instances. Consider making a local variable 
pointer instead. Actually we could make two pointers for 
smem_parts->part and mtd_parts and increment both in the loop to make 
tighter code.

> +	}
> +
> +	*pparts = mtd_parts;

Oh we already have the pointer, so just do this assignment before iterating.

On Thu, Aug 13, 2015 at 05:38:02PM -0700, Stephen Boyd wrote:
> On 08/13/2015 02:33 PM, Mathieu Olivari wrote:
> >diff --git a/drivers/mtd/qcom_smem_part.c b/drivers/mtd/qcom_smem_part.c
> >new file mode 100644
> >index 0000000..6cbf610
> >--- /dev/null
> >+++ b/drivers/mtd/qcom_smem_part.c
> >
> >+#define SMEM_PARTS_MAX			32
> >+
> >+struct smem_partition {
> >+	char name[SMEM_PART_NAME_SZ];
> >+	uint32_t start;
> >+	uint32_t size;
> >+	uint32_t attr;
> 
> Is this little endian? __le32? I think so.
Yes. I'll make the change.
> 
> >+};
> >+
> >+struct smem_partition_table {
> >+	uint32_t magic[2];
> >+	uint32_t version;
> >+	uint32_t len;
> 
> Same for these being little endian. And if so, please make magic into a byte
> array of size 8 and then do a memcmp with another static byte array.
Done.
> 
> >+	struct smem_partition parts[SMEM_PARTS_MAX];
> >+};
> >+
> >+static int qcom_smem_get_flash_blksz(uint64_t **smem_blksz)
> 
> I don't know, but I prefer u64 because it's short and sweet. But I'm not the
> maintainer here.
Agreed.
> 
> >+{
> >+	int ret;
> >+	size_t size;
> >+
> >+	ret = qcom_smem_get(SMEM_HOST_APPS, SMEM_BOOT_FLASH_BLOCK_SIZE,
> >+			    (void **) smem_blksz, &size);
> 
> Is the cast necessary?
Compiler will issue a warning if it's not there.
> 
> >+
> >+	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;
> >+	}
> >+
> >+	return 0;
> >+}
> >+
> >+static int qcom_smem_get_flash_type(uint64_t **smem_flash_type)
> >+{
> >+	int ret;
> >+	size_t size;
> >+
> >+	ret = qcom_smem_get(SMEM_HOST_APPS, 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;
> >+	}
> >+
> >+	return 0;
> >+}
> >+
> >+static int qcom_smem_get_flash_partitions(struct smem_partition_table **pparts)
> >+{
> >+	int ret;
> >+	size_t size;
> >+
> >+	ret = qcom_smem_get(SMEM_HOST_APPS, SMEM_AARM_PARTITION_TABLE,
> >+			    (void **) pparts, &size);
> >+
> >+	if (ret < 0) {
> >+		pr_err("Unable to read partition table from SMEM\n");
> >+		return -ENOENT;
> >+	}
> >+
> >+	return 0;
> >+}
> >+
> >+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);
> 
> I'm pretty sure this holds a reference to the device that needs to be
> released with put_device().
You're right. I'll add the corresponding put_device().
> 
> >+	return dev ? true : false;
> >+}
> >+
> >+static int parse_qcom_smem_partitions(struct mtd_info *master,
> >+				      struct mtd_partition **pparts,
> >+				      struct mtd_part_parser_data *data)
> >+{
> >+	struct smem_partition_table *smem_parts;
> >+	uint64_t *smem_flash_type, *smem_blksz;
> >+	struct mtd_partition *mtd_parts;
> >+	struct device_node *of_node = data->of_node;
> >+	int i, ret;
> >+
> >+	/*
> >+	 * SMEM will only store the partition table of the boot device.
> >+	 * If this is not the boot device, do not return any partition.
> >+	 */
> >+	ret = qcom_smem_get_flash_type(&smem_flash_type);
> >+	if (ret < 0)
> >+		return ret;
> >+
> >+	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;
> >+
> >+	/*
> >+	 * Just for sanity purpose, make sure the block size in SMEM matches the
> >+	 * block size of the MTD device
> >+	 */
> >+	ret = qcom_smem_get_flash_blksz(&smem_blksz);
> >+	if (ret < 0)
> >+		return ret;
> >+
> >+	if (*smem_blksz != master->erasesize) {
> >+		pr_err("SMEM block size differs from MTD block size\n");
> >+		return -EINVAL;
> >+	}
> >+
> >+	/* Get partition pointer from SMEM */
> >+	ret = qcom_smem_get_flash_partitions(&smem_parts);
> >+	if (ret < 0)
> >+		return ret;
> >+
> >+	if (smem_parts->magic[0] != SMEM_PTABLE_MAGIC_1 ||
> >+	    smem_parts->magic[1] != SMEM_PTABLE_MAGIC_2) {
> >+		pr_err("SMEM partition magic invalid\n");
> >+		return -EINVAL;
> >+	}
> >+
> >+	/* Allocate and populate the mtd structures */
> >+	mtd_parts = kcalloc(smem_parts->len, sizeof(struct mtd_partition),
> 
> sizeof(*mtd_parts)?
OK.
> 
> >+			    GFP_KERNEL);
> >+	if (mtd_parts == NULL)
> 
> if (!mtd_parts) is more kernel style.
OK.
> 
> >+		return -ENOMEM;
> >+
> >+	for (i = 0; i < smem_parts->len; i++) {
> >+		struct smem_partition *part = &smem_parts->parts[i];
> >+
> >+		mtd_parts[i].name = part->name;
> >+		mtd_parts[i].size = part->size * (*smem_blksz);
> >+		mtd_parts[i].offset = 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[i].offset + mtd_parts[i].size > master->size)
> >+			mtd_parts[i].size = master->size - mtd_parts[i].offset;
> 
> That is 7 mtd_parts[i]. instances. Consider making a local variable pointer
> instead. Actually we could make two pointers for smem_parts->part and
> mtd_parts and increment both in the loop to make tighter code.
OK; I'll simplify it by making a new pointer.
> 
> >+	}
> >+
> >+	*pparts = mtd_parts;
> 
> Oh we already have the pointer, so just do this assignment before iterating.
pparts is an argument; I'd rather not make double use of it for clarity
purpose. I'll create a new one similar to the SMEM one instead.
> 
> -- 
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
> a Linux Foundation Collaborative Project
>