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    Subject[PATCH] soc: qcom: cmd-db: Make endian-agnostic
    Date
    This driver deals with memory that is stored in little-endian format.
    Update the structures with the proper little-endian types and then
    do the proper conversions when reading the fields. Note that we compare
    the ids with a memcmp() because we already pad out the string 'id' field
    to exactly 8 bytes with the strncpy() onto the stack.

    Cc: Mahesh Sivasubramanian <msivasub@codeaurora.org>
    Cc: Lina Iyer <ilina@codeaurora.org>
    Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
    Cc: Evan Green <evgreen@chromium.org>
    Signed-off-by: Stephen Boyd <swboyd@chromium.org>
    ---

    Changes from inline patch:
    * Fixed magic
    * Made function for memcmp()
    *

    drivers/soc/qcom/cmd-db.c | 116 +++++++++++++++++++++-----------------
    1 file changed, 65 insertions(+), 51 deletions(-)

    diff --git a/drivers/soc/qcom/cmd-db.c b/drivers/soc/qcom/cmd-db.c
    index b5172049f608..88723b66afbc 100644
    --- a/drivers/soc/qcom/cmd-db.c
    +++ b/drivers/soc/qcom/cmd-db.c
    @@ -13,18 +13,9 @@

    #define NUM_PRIORITY 2
    #define MAX_SLV_ID 8
    -#define CMD_DB_MAGIC 0x0C0330DBUL
    #define SLAVE_ID_MASK 0x7
    #define SLAVE_ID_SHIFT 16

    -#define ENTRY_HEADER(hdr) ((void *)cmd_db_header + \
    - sizeof(*cmd_db_header) + \
    - hdr->header_offset)
    -
    -#define RSC_OFFSET(hdr, ent) ((void *)cmd_db_header + \
    - sizeof(*cmd_db_header) + \
    - hdr.data_offset + ent.offset)
    -
    /**
    * struct entry_header: header for each entry in cmddb
    *
    @@ -35,11 +26,11 @@
    * @offset: offset from :@data_offset, start of the data
    */
    struct entry_header {
    - u64 id;
    - u32 priority[NUM_PRIORITY];
    - u32 addr;
    - u16 len;
    - u16 offset;
    + u8 id[8];
    + __le32 priority[NUM_PRIORITY];
    + __le32 addr;
    + __le16 len;
    + __le16 offset;
    };

    /**
    @@ -53,12 +44,12 @@ struct entry_header {
    * @reserved: reserved for future use.
    */
    struct rsc_hdr {
    - u16 slv_id;
    - u16 header_offset;
    - u16 data_offset;
    - u16 cnt;
    - u16 version;
    - u16 reserved[3];
    + __le16 slv_id;
    + __le16 header_offset;
    + __le16 data_offset;
    + __le16 cnt;
    + __le16 version;
    + __le16 reserved[3];
    };

    /**
    @@ -72,11 +63,11 @@ struct rsc_hdr {
    * @data: driver specific data
    */
    struct cmd_db_header {
    - u32 version;
    - u32 magic_num;
    + __le32 version;
    + __le32 magic_num;
    struct rsc_hdr header[MAX_SLV_ID];
    - u32 checksum;
    - u32 reserved;
    + __le32 checksum;
    + __le32 reserved;
    u8 data[];
    };

    @@ -99,8 +90,34 @@ struct cmd_db_header {
    * h/w accelerator and request a resource state.
    */

    +static const char CMD_DB_MAGIC[] = { 0xdb, 0x30, 0x03, 0x0c };
    +
    +static bool cmd_db_magic_matches(struct cmd_db_header *header)
    +{
    + __le32 *magic = &header->magic_num;
    +
    + return memcmp(magic, CMD_DB_MAGIC, sizeof(CMD_DB_MAGIC)) == 0;
    +}
    +
    static struct cmd_db_header *cmd_db_header;

    +
    +static inline void *rsc_to_entry_header(struct rsc_hdr *hdr)
    +{
    + u16 offset = le16_to_cpu(hdr->header_offset);
    +
    + return cmd_db_header->data + offset;
    +}
    +
    +static inline void *
    +rsc_offset(struct rsc_hdr *hdr, struct entry_header *ent)
    +{
    + u16 offset = le16_to_cpu(hdr->header_offset);
    + u16 loffset = le16_to_cpu(ent->offset);
    +
    + return cmd_db_header->data + offset + loffset;
    +}
    +
    /**
    * cmd_db_ready - Indicates if command DB is available
    *
    @@ -110,29 +127,20 @@ int cmd_db_ready(void)
    {
    if (cmd_db_header == NULL)
    return -EPROBE_DEFER;
    - else if (cmd_db_header->magic_num != CMD_DB_MAGIC)
    + else if (!cmd_db_magic_matches(cmd_db_header))
    return -EINVAL;

    return 0;
    }
    EXPORT_SYMBOL(cmd_db_ready);

    -static u64 cmd_db_get_u64_id(const char *id)
    -{
    - u64 rsc_id = 0;
    - u8 *ch = (u8 *)&rsc_id;
    -
    - strncpy(ch, id, min(strlen(id), sizeof(rsc_id)));
    -
    - return rsc_id;
    -}
    -
    -static int cmd_db_get_header(u64 query, struct entry_header *eh,
    +static int cmd_db_get_header(const char *id, struct entry_header *eh,
    struct rsc_hdr *rh)
    {
    struct rsc_hdr *rsc_hdr;
    struct entry_header *ent;
    int ret, i, j;
    + char query[8];

    ret = cmd_db_ready();
    if (ret)
    @@ -141,18 +149,21 @@ static int cmd_db_get_header(u64 query, struct entry_header *eh,
    if (!eh || !rh)
    return -EINVAL;

    + /* Pad out query string to same length as in DB */
    + strncpy(query, id, sizeof(query));
    +
    for (i = 0; i < MAX_SLV_ID; i++) {
    rsc_hdr = &cmd_db_header->header[i];
    if (!rsc_hdr->slv_id)
    break;

    - ent = ENTRY_HEADER(rsc_hdr);
    - for (j = 0; j < rsc_hdr->cnt; j++, ent++) {
    - if (ent->id == query)
    + ent = rsc_to_entry_header(rsc_hdr);
    + for (j = 0; j < le16_to_cpu(rsc_hdr->cnt); j++, ent++) {
    + if (memcmp(ent->id, query, sizeof(ent->id)))
    break;
    }

    - if (j < rsc_hdr->cnt) {
    + if (j < le16_to_cpu(rsc_hdr->cnt)) {
    memcpy(eh, ent, sizeof(*ent));
    memcpy(rh, rsc_hdr, sizeof(*rh));
    return 0;
    @@ -166,9 +177,7 @@ static int cmd_db_get_header_by_rsc_id(const char *id,
    struct entry_header *ent_hdr,
    struct rsc_hdr *rsc_hdr)
    {
    - u64 rsc_id = cmd_db_get_u64_id(id);
    -
    - return cmd_db_get_header(rsc_id, ent_hdr, rsc_hdr);
    + return cmd_db_get_header(id, ent_hdr, rsc_hdr);
    }

    /**
    @@ -189,7 +198,7 @@ u32 cmd_db_read_addr(const char *id)

    ret = cmd_db_get_header_by_rsc_id(id, &ent, &rsc_hdr);

    - return ret < 0 ? 0 : ent.addr;
    + return ret < 0 ? 0 : le32_to_cpu(ent.addr);
    }
    EXPORT_SYMBOL(cmd_db_read_addr);

    @@ -207,6 +216,7 @@ int cmd_db_read_aux_data(const char *id, u8 *data, size_t len)
    int ret;
    struct entry_header ent;
    struct rsc_hdr rsc_hdr;
    + u16 ent_len;

    if (!data)
    return -EINVAL;
    @@ -215,11 +225,12 @@ int cmd_db_read_aux_data(const char *id, u8 *data, size_t len)
    if (ret)
    return ret;

    - if (len < ent.len)
    + ent_len = le16_to_cpu(ent.len);
    + if (len < ent_len)
    return -EINVAL;

    - len = min_t(u16, ent.len, len);
    - memcpy(data, RSC_OFFSET(rsc_hdr, ent), len);
    + len = min_t(u16, ent_len, len);
    + memcpy(data, rsc_offset(&rsc_hdr, &ent), len);

    return len;
    }
    @@ -240,7 +251,7 @@ size_t cmd_db_read_aux_data_len(const char *id)

    ret = cmd_db_get_header_by_rsc_id(id, &ent, &rsc_hdr);

    - return ret < 0 ? 0 : ent.len;
    + return ret < 0 ? 0 : le16_to_cpu(ent.len);
    }
    EXPORT_SYMBOL(cmd_db_read_aux_data_len);

    @@ -256,11 +267,14 @@ enum cmd_db_hw_type cmd_db_read_slave_id(const char *id)
    int ret;
    struct entry_header ent;
    struct rsc_hdr rsc_hdr;
    + u32 addr;

    ret = cmd_db_get_header_by_rsc_id(id, &ent, &rsc_hdr);
    + if (ret < 0)
    + return CMD_DB_HW_INVALID;

    - return ret < 0 ? CMD_DB_HW_INVALID :
    - (ent.addr >> SLAVE_ID_SHIFT) & SLAVE_ID_MASK;
    + addr = le32_to_cpu(ent.addr);
    + return (addr >> SLAVE_ID_SHIFT) & SLAVE_ID_MASK;
    }
    EXPORT_SYMBOL(cmd_db_read_slave_id);

    @@ -282,7 +296,7 @@ static int cmd_db_dev_probe(struct platform_device *pdev)
    return ret;
    }

    - if (cmd_db_header->magic_num != CMD_DB_MAGIC) {
    + if (cmd_db_magic_matches(cmd_db_header)) {
    dev_err(&pdev->dev, "Invalid Command DB Magic\n");
    return -EINVAL;
    }
    --
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