Hi Boris,
On 2018/8/2 5:50, Boris Brezillon wrote:
Hi Yixun,
On Thu, 19 Jul 2018 17:46:12 +0800
Yixun Lan <yixun.lan@xxxxxxxxxxx> wrote:
I haven't finished reviewing the driver yet (I'll try to do that later
this week), but I already pointed a few things to fix/improve.
+
+static int meson_nfc_exec_op(struct nand_chip *chip,
+ const struct nand_operation *op, bool check_only)
+{
+ struct mtd_info *mtd = nand_to_mtd(chip);
+ struct meson_nfc *nfc = nand_get_controller_data(chip);
+ const struct nand_op_instr *instr = NULL;
+ int ret = 0, cmd;
+ unsigned int op_id;
+ int i;
+
+ for (op_id = 0; op_id < op->ninstrs; op_id++) {
+ instr = &op->instrs[op_id];
+ switch (instr->type) {
+ case NAND_OP_CMD_INSTR:
+ cmd = nfc->param.chip_select | NFC_CMD_CLE;
+ cmd |= instr->ctx.cmd.opcode & 0xff;
+ writel(cmd, nfc->reg_base + NFC_REG_CMD);
+ meson_nfc_cmd_idle(nfc, NAND_TWB_TIME_CYCLE);
This is not necessarily TWB you have to wait after a CMD cycle. It can
be tWHR. And you should definitely not hardcode the value, since,
AFAIR, it depends on the selected SDR timings. Probably something you
should calculate in ->setup_data_interface().
Indeed. TWB is not necessarily. And tWHR will be promised by NFC.
so I will delete it.
+ meson_nfc_drain_cmd(nfc);
I don't know exactly how the NAND controller works, but it's usually
not a good idea to execute the operation right away, especially if you
have address/cmd/data cycles following this cmd and those can be
packed in the same controller operation.
it doesn't need meson_nfc_drain_cmd(nfc) here. i will delete it next version
+ break;
+
+ case NAND_OP_ADDR_INSTR:
+ for (i = 0; i < instr->ctx.addr.naddrs; i++) {
+ cmd = nfc->param.chip_select | NFC_CMD_ALE;
+ cmd |= instr->ctx.addr.addrs[i] & 0xff;
+ writel(cmd, nfc->reg_base + NFC_REG_CMD);
+ }
+ break;
+
+ case NAND_OP_DATA_IN_INSTR:
+ meson_nfc_read_buf(mtd, instr->ctx.data.buf.in,
+ instr->ctx.data.len);
+ break;
+
+ case NAND_OP_DATA_OUT_INSTR:
+ meson_nfc_write_buf(mtd, instr->ctx.data.buf.out,
+ instr->ctx.data.len);
Well, I'm not entirely sure what happens when you call
read/write_buf(), but it seems you're doing that one byte at a time,
and that sounds not so efficient given the operation you do for each
byte read/written. Don't you have a way to tell the engine that you
want to read/write X bytes?
As i known, there is no way to read/write X bytes once.
+ break;
+
+ case NAND_OP_WAITRDY_INSTR:
+ mdelay(instr->ctx.waitrdy.timeout_ms);
+ ret = nand_soft_waitrdy(chip,
+ instr->ctx.waitrdy.timeout_ms);
Hm, i'd be surprised if the controller does not have a way to optimize
waits on R/B transitions.
When i delete the delay here, erasing operation will be failed.
Does it mean NFC send 0x70 to nand device when rb is busy(low)?
If so, i will ask our NFC designer for comfirmation or grasping the waveform.
+ break;
+ }
+ }
+ return ret;
+}
+
+static int meson_ooblayout_ecc(struct mtd_info *mtd, int section,
+ struct mtd_oob_region *oobregion)
+{
+ struct nand_chip *chip = mtd_to_nand(mtd);
+ int free_oob;
+
+ if (section >= chip->ecc.steps)
+ return -ERANGE;
+
+ free_oob = (section + 1) * 2;
+ oobregion->offset = section * chip->ecc.bytes + free_oob;
Hm, this offset calculation looks weird. Are you sure it's correct?
I'd bet on something like:
oobregion->offset = 2 + (section * (chip->ecc.bytes + 4));
Each ecc page have 2 user bytes. Assume one 2KB+64B page size nand
flash using ECC8/1KB which ecc parity bytes is 14B.
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
| | | | | | | not |
| 1KB |2B| 14B | 1KB |2B| 14B | used | (layout on nand)
|_ _ _ _ _ _ _|_ |_ _ _ | _ _ _ _ _ _ |_ |_ _ _|_ _ _ _|
(2KB + 64B)
when reading from nand, I will format the page as follow:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
| | | | | | | not |
| 1KB | 1KB |2B| 14B |2B| 14B | used |(layout on ddr)
|_ _ _ _ _ _ _|_ _ _ _ _ _ _|_ |_ _ _|_ |_ _ _ |_ _ _ _|
(2KB + 64B)
So i get "oobregion->offset = section * chip->ecc.bytes + free_oob".
Maybe i don't get what does 'section' mean. i think it means the ecc page number.
+ oobregion->length = chip->ecc.bytes;
+
+ return 0;
+}
+
+static int meson_ooblayout_free(struct mtd_info *mtd, int section,
+ struct mtd_oob_region *oobregion)
+{
+ struct nand_chip *chip = mtd_to_nand(mtd);
+
+ if (section >= chip->ecc.steps)
+ return -ERANGE;
+
+ oobregion->offset = section * (2 + chip->ecc.bytes);
+ oobregion->length = 2;
+
+ return 0;
+}
+
+static const struct mtd_ooblayout_ops meson_ooblayout_ops = {
+ .ecc = meson_ooblayout_ecc,
+ .free = meson_ooblayout_free,
+};
+
+static int meson_nfc_ecc_init(struct device *dev, struct mtd_info *mtd)
+{
+ struct nand_chip *nand = mtd_to_nand(mtd);
+ struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
+ struct meson_nfc *nfc = nand_get_controller_data(nand);
+ const struct meson_nand_ecc *meson_ecc = nfc->data->ecc;
+ int num = nfc->data->ecc_num;
+ int nsectors, i, bytes;
+
+ /* support only ecc hw mode */
+ if (nand->ecc.mode != NAND_ECC_HW) {
+ dev_err(dev, "ecc.mode not supported\n");
+ return -EINVAL;
+ }
+
+ if (!nand->ecc.size || !nand->ecc.strength) {
+ /* use datasheet requirements */
+ nand->ecc.strength = nand->ecc_strength_ds;
+ nand->ecc.size = nand->ecc_step_ds;
+ }
+
+ if (nand->ecc.options & NAND_ECC_MAXIMIZE) {
+ nand->ecc.size = 1024;
+ nsectors = mtd->writesize / nand->ecc.size;
+ bytes = mtd->oobsize - 2 * nsectors;
+ bytes /= nsectors;
+
+ /* and bytes has to be even. */
+ if (bytes % 2)
+ bytes--;
+
+ nand->ecc.strength = bytes * 8 / fls(8 * nand->ecc.size);
+ } else {
+ if (nand->ecc.strength > meson_ecc[num - 1].strength) {
+ dev_err(dev, "not support ecc strength\n");
+ return -EINVAL;
+ }
+ }
+
+ for (i = 0; i < num; i++) {
+ if (meson_ecc[i].strength == 0xff ||
+ nand->ecc.strength < meson_ecc[i].strength)
+ break;
+ }
I'd suggest that you look at nand_match_ecc_req(). It's likely that the
selection logic you have here can be replaced by the generic function.
em, I will try it next version.
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