On Fri 14 Aug 17:46 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.
>
Nice to see another user of the smem code :)
> diff --git a/drivers/mtd/qcom_smem_part.c b/drivers/mtd/qcom_smem_part.c
[..]
> +
> +/* Processor/host identifier for the application processor */
> +#define SMEM_HOST_APPS 0
This makes me wonder if there will ever be an apps partition. I would
have picked QCOM_SMEM_HOST_ANY, but I don't know what future platforms
might hold for us.
And as a side note, I think I will propose that we rename that define
QCOM_SMEM_GLOBAL.
> +
> +/* 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(u64 **smem_blksz)
Instead of passing pointers around I think you should just make this
function return < 0 for errors and >= 0 for the requested data. You can
probably still have it as an int, as the current values are well below
the size of the int.
> +{
> + int ret;
> + size_t size;
> +
> + ret = qcom_smem_get(SMEM_HOST_APPS, 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;
> + }
> +
> + return 0;
> +}
> +
> +static int qcom_smem_get_flash_type(u64 **smem_flash_type)
Same as above.
> +{
> + 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 you don't care about the size just pass NULL as the last argument.
> + if (ret < 0) {
> + pr_err("Unable to read partition table from SMEM\n");
> + return -ENOENT;
> + }
I think it would be cleaner if you had this function check the magic and
version and then return the partition pointer. That is:
static smem_partition *qcom_smem_get_flash_partitions(size_t *count)
And make *count = le32_to_cpu(table->len); so you don't have to care
about that below.
(And use NULL or ERR_PTR for the error paths)
> +
> + 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);
> + 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_table *smem_parts;
> + u64 *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.
> + */
I guess this is the result of below checks, but it's not describing
what's actually done here. I think it should say "only parse
partitions on the specified memory type" or something like that.
> + 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
> + */
Well, this is not only for sanity purpose, as you multiply all sizes
with this number below...
> + 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 (memcmp(SMEM_PTABLE_MAGIC, smem_parts->magic,
> + sizeof(SMEM_PTABLE_MAGIC))) {
> + pr_err("SMEM partition magic invalid\n");
> + return -EINVAL;
> + }
> +
> + /* Allocate and populate the mtd structures */
> + mtd_parts = kcalloc(le32_to_cpu(smem_parts->len), sizeof(*mtd_parts),
> + GFP_KERNEL);
> + if (!mtd_parts)
> + return -ENOMEM;
> +
> + for (i = 0; i < smem_parts->len; i++) {
This might have the wrong endian...
> + struct smem_partition *s_part = &smem_parts->parts[i];
> + struct mtd_partition *m_part = &mtd_parts[i];
I think Stephens suggestion was that you assign *pparts before looping
and then you simply do:
*pparts = mtd_parts;
while (len--) {
..
s_part++;
mtd_parts++;
}
> +
> + m_part->name = s_part->name;
I tried to follow the mtd code, and I believe that this pointer might
be freed in free_partition(). If so you must kstrdup it here.
> + m_part->size = le32_to_cpu(s_part->size) * (*smem_blksz);
> + m_part->offset = le32_to_cpu(s_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 (m_part->offset + m_part->size > master->size)
> + m_part->size = master->size - m_part->offset;
> + }
> +
> + *pparts = mtd_parts;
> +
> + return smem_parts->len;
Again, this might be in the wrong endian.
> +}
> +
> +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);
Mostly unrelated to this patch; This makes me appreciate the
module_platform_driver() macro, would be nice to see a patch that
introduces something similar for partition parsers.
> +
> +MODULE_LICENSE("GPL");
Are you sure you don't mean "GPL v2" here?
> +MODULE_AUTHOR("Mathieu Olivari <mathieu@xxxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Parsing code for SMEM based partition tables");
Regards,
Bjorn
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
