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Message-ID: <20180423172230.GD18235@codeaurora.org>
Date: Mon, 23 Apr 2018 11:22:30 -0600
From: Lina Iyer <ilina@...eaurora.org>
To: Stephen Boyd <swboyd@...omium.org>
Cc: Andy Gross <andy.gross@...aro.org>, linux-arm-msm@...r.kernel.org,
linux-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
Mahesh Sivasubramanian <msivasub@...eaurora.org>,
Bjorn Andersson <bjorn.andersson@...aro.org>,
Evan Green <evgreen@...omium.org>
Subject: Re: [PATCH v3] soc: qcom: cmd-db: Make endian-agnostic
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@...eaurora.org>
>Cc: Lina Iyer <ilina@...eaurora.org>
>Cc: Bjorn Andersson <bjorn.andersson@...aro.org>
>Cc: Evan Green <evgreen@...omium.org>
>Signed-off-by: Stephen Boyd <swboyd@...omium.org>
>---
>
Tested-by: Lina Iyer <ilina@...eaurora.org>
>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;
> }
>--
>Sent by a computer through tubes
>
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