Re: [PATCH v3] soc: qcom: cmd-db: Make endian-agnostic
From: Lina Iyer
Date: Mon Apr 23 2018 - 13:22:45 EST
On Mon, Apr 23 2018 at 10:21 -0600, Stephen Boyd wrote:
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@xxxxxxxxxxxxxx>
Cc: Lina Iyer <ilina@xxxxxxxxxxxxxx>
Cc: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
Cc: Evan Green <evgreen@xxxxxxxxxxxx>
Signed-off-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>
---
Tested-by: Lina Iyer <ilina@xxxxxxxxxxxxxx>
Changes from v2:
* Fixed rsc_offset conversion to use data_offset instead of header_offset
for finding first offset
* Tested and confirmed slave ids and aux data for ARC regulators look
the same as before
Changes from v1:
* Fixed negation on probe time magic matches check to be correct
* Fixed kernel doc and renamed magic_num to magic
* Killed cmd_db_get_header_by_rsc_id() entirely
* Changed chars to u8s for simplicity of thinking about signedness
* Fixed cmd_db_get_header()'s memcmp to do the right thing by checking
for a match instead of the opposite
* Tested on real hardware
drivers/soc/qcom/cmd-db.c | 131 ++++++++++++++++++++------------------
1 file changed, 69 insertions(+), 62 deletions(-)
diff --git a/drivers/soc/qcom/cmd-db.c b/drivers/soc/qcom/cmd-db.c
index b5172049f608..a6f646295f06 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;
};
/**
@@ -53,30 +44,30 @@ 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];
};
/**
* struct cmd_db_header: The DB header information
*
* @version: The cmd db version
- * @magic_number: constant expected in the database
+ * @magic: constant expected in the database
* @header: array of resources
* @checksum: checksum for the header. Unused.
* @reserved: reserved memory
* @data: driver specific data
*/
struct cmd_db_header {
- u32 version;
- u32 magic_num;
+ __le32 version;
+ u8 magic[4];
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 u8 CMD_DB_MAGIC[] = { 0xdb, 0x30, 0x03, 0x0c };
+
+static bool cmd_db_magic_matches(const struct cmd_db_header *header)
+{
+ const u8 *magic = header->magic;
+
+ return memcmp(magic, CMD_DB_MAGIC, ARRAY_SIZE(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->data_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;
+ u8 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)) == 0)
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;
@@ -162,15 +173,6 @@ static int cmd_db_get_header(u64 query, struct entry_header *eh,
return -ENODEV;
}
-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);
-}
-
/**
* cmd_db_read_addr() - Query command db for resource id address.
*
@@ -187,9 +189,9 @@ u32 cmd_db_read_addr(const char *id)
struct entry_header ent;
struct rsc_hdr rsc_hdr;
- ret = cmd_db_get_header_by_rsc_id(id, &ent, &rsc_hdr);
+ ret = cmd_db_get_header(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);
@@ -207,19 +209,21 @@ 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;
- ret = cmd_db_get_header_by_rsc_id(id, &ent, &rsc_hdr);
+ ret = cmd_db_get_header(id, &ent, &rsc_hdr);
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;
}
@@ -238,9 +242,9 @@ size_t cmd_db_read_aux_data_len(const char *id)
struct entry_header ent;
struct rsc_hdr rsc_hdr;
- ret = cmd_db_get_header_by_rsc_id(id, &ent, &rsc_hdr);
+ ret = cmd_db_get_header(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 +260,14 @@ 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);
+ ret = cmd_db_get_header(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 +289,7 @@ 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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