[U-Boot] [PATCH v3 3/7] dfu: DFU backend implementation

Lukasz Majewski
2012-08-02T13:55:24Z

Dear Mike Frysinger,

> On Tuesday 31 July 2012 02:36:59 Lukasz Majewski wrote:
> > --- /dev/null
> > +++ b/drivers/dfu/dfu.c
> >
> > +static int dfu_find_alt_num(char *s)
>
> const char *s
Good point.
>
> > +{
> > + int i = 0;
> > +
> > + for (; *s; s++)
> > + if (*s == ';')
> > + i++;
> > +
> > + return ++i;
> > +}

In this function I count how many times the ';' separator appears.
I didn't found proper function at ./lib/string.c.

>
> looks kind of like:
> return (strrchr(s, ';') - s) + 1;

The above code returns position of the last occurrence of the ';'
separator.

>
> > +int dfu_write(struct dfu_entity *dfu, void *buf, int size, int
> > blk_seq_num) +{
> > + static unsigned char *i_buf;
> > + static int i_blk_seq_num;
> > + long w_size = 0;
> > + int ret = 0;
> > +
> > + if (blk_seq_num == 0) {
> > + memset(dfu_buf, '\0', sizeof(dfu_buf));
> > ...
> > + memcpy(i_buf, buf, size);
> > + i_buf += size;
>
> why bother clearing it ? since right below we memcpy() in the data
> we care about from buf, i'd skip the memset() completely.
You are right, removed.
>
> > +int dfu_read(struct dfu_entity *dfu, void *buf, int size, int
> > blk_seq_num) +{
> > + static unsigned char *i_buf;
> > + static int i_blk_seq_num;
> > + static long r_size;
> > + static u32 crc;
> > + int ret = 0;
> > +
> > + if (blk_seq_num == 0) {
> > + i_buf = dfu_buf;
> > + memset(dfu_buf, '\0', sizeof(dfu_buf));
> > + ret = dfu->read_medium(dfu, i_buf, &r_size);
> > + debug("%s: %s %ld [B]\n", __func__, dfu->name,
> > r_size);
> > + i_blk_seq_num = 0;
> > + /* Integrity check (if needed) */
> > + crc = crc32(0, dfu_buf, r_size);
> > + }
>
> same here -- punt the memset()
OK,
>
> > +static int dfu_fill_entity(struct dfu_entity *dfu, char* s, int
> > alt,
>
> "char *s", not "char* s"
OK,
>
> > +int dfu_config_entities(char *env, char *interface, int num)
> > +{
> > + struct dfu_entity *dfu;
> > + int i, ret;
> > + char *s;
> > +
> > + dfu_alt_num = dfu_find_alt_num(env);
> > + debug("%s: dfu_alt_num=%d\n", __func__, dfu_alt_num);
> > +
> > + for (i = 0; i < dfu_alt_num; i++) {
> > + dfu = calloc(sizeof(struct dfu_entity), 1);
>
> seems like you can do this in a single call outside of the for loop:
> dfu = calloc(sizeof(*dfu), dfu_alt_num);
> if (!dfu)
> return -1;
> for (i = 0; i < dfu_alt_num; i++) {
> s = strsep(&env, ";");
> ret = dfu_fill_entity(&dfu[i], s, i, interface, num);
> if (ret)
> return -1;
> list_add_tail(&dfu[i].list, &dfu_list);
> }
>

I'd prefer to leave it as it is (since IMHO is more readable) with the
addition of following code:

for (i = 0; i < dfu_alt_num; i++) {
dfu = calloc(sizeof(struct dfu_entity), 1);
if (!dfu) {
dfu_free_entities();
return -1;
}
}

> > --- /dev/null
> > +++ b/include/dfu.h
> >
> > +char *dfu_extract_token(char** e, int *n);
> > +extern int dfu_fill_entity_mmc(struct dfu_entity *dfu, char* s);
> > +static inline int dfu_fill_entity_mmc(struct dfu_entity *dfu,
> > char* s)
>
> "char *s", not "char* s"
OK
> -mike

--
Best regards,

Lukasz Majewski

Samsung Poland R&D Center | Linux Platform Group