Hi Boris,
Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx> wrote on Sun, 10 May
2020 09:02:30 +0200:
> On Fri, 8 May 2020 19:13:38 +0200
> Miquel Raynal <miquel.raynal@xxxxxxxxxxx> wrote:
>
> > +static int anfc_len_to_steps(struct nand_chip *chip, unsigned int len)
> > +{
> > + unsigned int steps = 1, pktsize = len;
> > +
> > + while (pktsize > ANFC_MAX_PKT_SIZE) {
> > + steps *= 2;
> > + pktsize = DIV_ROUND_UP(len, steps);
> > + }
>
>
> Same here, you shouldn't have a round_up() but instead complain if
> "len != pkt_size * steps"
>
> if (len % 4)
> return -ENOTSUPP;
>
> if (len < ANFC_MAX_PKT_SIZE)
> return len;
>
> for (steps = 2; steps < ANFC_MAX_STEPS; steps *= 2) {
> pkt_size = len / steps;
> if (pkt_size <= ANFC_MAX_PKT_SIZE)
> break;
> }
>
> if (pkt_size * steps != len)
> return -ENOTSUPP;
>
> return pkt_size;
>
> > +
> > + if (steps > ANFC_MAX_STEPS)
> > + return -ENOTSUPP;
> > +
> > + return steps;
> > +}
I took the logic of the above proposal and extended the helper to be
"anfc_pkt_len_config", taking two pointers as argument: *steps and
*pktsize, which will be updated in case of success. Otherwise
this function returns an error and can be added to the "check_op" path
instead of only failing at execution time.
---8<---
+static int anfc_pkt_len_config(unsigned int len, unsigned int *steps,
+ unsigned int *pktsize)
+{
+ unsigned int nb, sz;
+
+ for (nb = 1; nb < ANFC_MAX_STEPS; nb *= 2) {
+ sz = len / nb;
+ if (sz <= ANFC_MAX_PKT_SIZE)
+ break;
+ }
+
+ if (sz * nb != len)
+ return -ENOTSUPP;
+
+ if (steps)
+ *steps = nb;
+
+ if (pktsize)
+ *pktsize = sz;
+
+ return 0;
+}
--->8---
And then, in anfc_check_op():
+ case NAND_OP_DATA_IN_INSTR:
+ case NAND_OP_DATA_OUT_INSTR:
+ if (instr->ctx.data.len > ANFC_MAX_CHUNK_SIZE)
+ return -ENOTSUPP;
+
+ if (anfc_pkt_len_config(instr->ctx.data.len NULL, NULL))
+ return -ENOTSUPP;
+
+ break;
