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Message-ID: <a6a20b50-02b0-53c0-1e65-75035bc59c87@amlogic.com>
Date: Thu, 8 Jun 2023 20:37:14 +0800
From: Liang Yang <liang.yang@...ogic.com>
To: Miquel Raynal <miquel.raynal@...tlin.com>,
Arseniy Krasnov <avkrasnov@...rdevices.ru>
Cc: Richard Weinberger <richard@....at>,
Vignesh Raghavendra <vigneshr@...com>,
Neil Armstrong <neil.armstrong@...aro.org>,
Kevin Hilman <khilman@...libre.com>,
Jerome Brunet <jbrunet@...libre.com>,
Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
oxffffaa@...il.com, kernel@...rdevices.ru,
linux-mtd@...ts.infradead.org,
linux-arm-kernel@...ts.infradead.org,
linux-amlogic@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] mtd: rawnand: meson: check buffer length
Hi Arseniy and Miquel,
On 2023/6/8 15:12, Liang Yang wrote:
> Hi Miquel,
>
> On 2023/6/8 14:54, Miquel Raynal wrote:
>> [ EXTERNAL EMAIL ]
>>
>> Hi Liang,
>>
>> liang.yang@...ogic.com wrote on Thu, 8 Jun 2023 14:42:53 +0800:
>>
>>> Hi Arseniy,
>>>
>>> On 2023/6/8 5:17, Arseniy Krasnov wrote:
>>>> [ EXTERNAL EMAIL ]
>>>>
>>>> Hi again Miquel, Liang!
>>>>
>>>> What do You think about this patch?
>>>>
>>>> Thanks, Arseniy
>>>>
>>>> On 06.06.2023 19:29, Arseniy Krasnov wrote:
>>>>> Sorry, here is changelog:
>>>>> v1 -> v2:
>>>>> * Move checks from 'switch/case' which executes commands in
>>>>> 'meson_nfc_exec_op()' to a special
>>>>> separated function 'meson_nfc_check_op()' which is called
>>>>> before commands processing.
>>>>>
>>>>> On 06.06.2023 13:16, Arseniy Krasnov wrote:
>>>>>> Meson NAND controller has limited buffer length, so check it before
>>>>>> command execution to avoid length trim. Also check MTD write size on
>>>>>> chip attach.
>>>>>>
>>>>>> Signed-off-by: Arseniy Krasnov <AVKrasnov@...rdevices.ru>
>>>>>> ---
>>>>>> drivers/mtd/nand/raw/meson_nand.c | 47
>>>>>> +++++++++++++++++++++++++++----
>>>>>> 1 file changed, 42 insertions(+), 5 deletions(-)
>>>>>>
>>>>>> diff --git a/drivers/mtd/nand/raw/meson_nand.c
>>>>>> b/drivers/mtd/nand/raw/meson_nand.c
>>>>>> index 23a73268421b..db6b18753071 100644
>>>>>> --- a/drivers/mtd/nand/raw/meson_nand.c
>>>>>> +++ b/drivers/mtd/nand/raw/meson_nand.c
>>>>>> @@ -111,6 +111,8 @@
>>>>>>
>>>>>> #define PER_INFO_BYTE 8
>>>>>>
>>>>>> +#define NFC_CMD_RAW_LEN GENMASK(13, 0)
>>>>>> +
>>>>>> struct meson_nfc_nand_chip {
>>>>>> struct list_head node;
>>>>>> struct nand_chip nand;
>>>>>> @@ -284,7 +286,7 @@ static void meson_nfc_cmd_access(struct
>>>>>> nand_chip *nand, int raw, bool dir,
>>>>>>
>>>>>> if (raw) {
>>>>>> len = mtd->writesize + mtd->oobsize;
>>>>>> - cmd = (len & GENMASK(13, 0)) | scrambler | DMA_DIR(dir);
>>>>>> + cmd = len | scrambler | DMA_DIR(dir);
>>>>>> writel(cmd, nfc->reg_base + NFC_REG_CMD);
>>>
>>> I think we could keep "& GENMASK(13, 0)". it is better here to
>>> indicate how many bits of length in this command and don't destory
>>> the command once we don't check the "len" outside of this function.
>>> or the code "if (len > NFC_CMD_RAW_LEN)" is better to put inside
>>> this function nearly. Thanks.
>>
>> It depends who calls this helper. If only used inside
>> exec_op,write_page_raw() and read_page_raw() also call
>> meson_nfc_cmd_access(),
> but i don't find where constrain the "len".
Is the helper "meson_nfc_check_op()" needed by exec_op() after the
constraint in attach_chip()? the length passed in exec_op() seems
smaller than "mtd->writesize + mtd->oobsize" now.
@Arseniy if it does need, I think the same constraint is needed by
"meson_nfc_cmd_access()"
>
>> it's not useful. If used outside, then if you want to clarify
>> things you may want to use:
>>
>> #define NFC_CMD_OP_LEN(cmd) FIELD_PREP(GENMASK(13, 0), (cmd))
>>
>> This is by far my favorite construction. Could apply to many other
>> fields, like DMA_DIR, scrambler, etc.
@Miquel, FIELD_PREP() is better, but i have no idea whether we should
add FIELD_PREP() in this patch, or keep the previous code.
>>
>>>>>> return;
>>>>>> }
>>>>>> @@ -573,7 +575,7 @@ static int meson_nfc_read_buf(struct nand_chip
>>>>>> *nand, u8 *buf, int len)
>>>>>> if (ret)
>>>>>> goto out;
>>>>>>
>>>>>> - cmd = NFC_CMD_N2M | (len & GENMASK(13, 0));
>>>>>> + cmd = NFC_CMD_N2M | len;
>>>>>> writel(cmd, nfc->reg_base + NFC_REG_CMD);
>>>>>>
>>>>>> meson_nfc_drain_cmd(nfc);
>>>>>> @@ -597,7 +599,7 @@ static int meson_nfc_write_buf(struct
>>>>>> nand_chip *nand, u8 *buf, int len)
>>>>>> if (ret)
>>>>>> return ret;
>>>>>>
>>>>>> - cmd = NFC_CMD_M2N | (len & GENMASK(13, 0));
>>>>>> + cmd = NFC_CMD_M2N | len;
>>>>>> writel(cmd, nfc->reg_base + NFC_REG_CMD);
>>>>>>
>>>>>> meson_nfc_drain_cmd(nfc);
>>>>>> @@ -1007,6 +1009,31 @@ meson_nand_op_put_dma_safe_output_buf(const
>>>>>> struct nand_op_instr *instr,
>>>>>> kfree(buf);
>>>>>> }
>>>>>>
>>>>>> +static int meson_nfc_check_op(struct nand_chip *chip,
>>>>>> + const struct nand_operation *op)
>>>>>> +{
>>>>>> + int op_id;
>>>>>> +
>>>>>> + for (op_id = 0; op_id < op->ninstrs; op_id++) {
>>>>>> + const struct nand_op_instr *instr;
>>>>>> +
>>>>>> + instr = &op->instrs[op_id];
>>>>>> +
>>>>>> + switch (instr->type) {
>>>>>> + case NAND_OP_DATA_IN_INSTR:
>>>>>> + case NAND_OP_DATA_OUT_INSTR:
>>>>>> + if (instr->ctx.data.len > NFC_CMD_RAW_LEN)
>>>>>> + return -ENOTSUPP;
>>>>>> +
>>>>>> + break;
>>>>>> + default:
>>>>>> + break;
>>>>>> + }
>>>>>> + }
>>>>>> +
>>>>>> + return 0;
>>>>>> +}
>>>>>> +
>>>>>> static int meson_nfc_exec_op(struct nand_chip *nand,
>>>>>> const struct nand_operation *op, bool
>>>>>> check_only)
>>>>>> {
>>>>>> @@ -1015,10 +1042,12 @@ static int meson_nfc_exec_op(struct
>>>>>> nand_chip *nand,
>>>>>> const struct nand_op_instr *instr = NULL;
>>>>>> void *buf;
>>>>>> u32 op_id, delay_idle, cmd;
>>>>>> + int err;
>>>>>> int i;
>>>>>>
>>>>>> - if (check_only)
>>>>>> - return 0;
>>>>>> + err = meson_nfc_check_op(nand, op);
>>>>>> + if (err || check_only)
>>>>>> + return err;
>>>>>>
>>>>>> meson_nfc_select_chip(nand, op->cs);
>>>>>> for (op_id = 0; op_id < op->ninstrs; op_id++) {
>>>>>> @@ -1293,6 +1322,7 @@ static int meson_nand_attach_chip(struct
>>>>>> nand_chip *nand)
>>>>>> struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
>>>>>> struct mtd_info *mtd = nand_to_mtd(nand);
>>>>>> int nsectors = mtd->writesize / 1024;
>>>>>> + int raw_writesize;
>>>>>> int ret;
>>>>>>
>>>>>> if (!mtd->name) {
>>>>>> @@ -1304,6 +1334,13 @@ static int meson_nand_attach_chip(struct
>>>>>> nand_chip *nand)
>>>>>> return -ENOMEM;
>>>>>> }
>>>>>>
>>>>>> + raw_writesize = mtd->writesize + mtd->oobsize;
>>>>>> + if (raw_writesize > NFC_CMD_RAW_LEN) {
>>>>>> + dev_err(nfc->dev, "too big write size in raw mode: %d
>>>>>> > %ld\n",
>>>>>> + raw_writesize, NFC_CMD_RAW_LEN);
>>>>>> + return -EINVAL;
>>>>>> + }
>>>>>> +
>>>>>> if (nand->bbt_options & NAND_BBT_USE_FLASH)
>>>>>> nand->bbt_options |= NAND_BBT_NO_OOB;
>>>>>>
>>
>>
>> Thanks,
>> Miquèl
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