| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <6c0b4c3c-fd7b-f6e9-34b3-27901c5c7d18@sberdevices.ru>
Date: Wed, 7 Jun 2023 10:31:26 +0300
From: Arseniy Krasnov <avkrasnov@...rdevices.ru>
To: Liang Yang <liang.yang@...ogic.com>,
Miquel Raynal <miquel.raynal@...tlin.com>,
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>
CC: <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 v1] mtd: rawnand: meson: waiting w/o wired ready/busy pin
On 07.06.2023 06:14, Liang Yang wrote:
> Hi Arseniy,
>
> On 2023/6/7 3:54, Arseniy Krasnov wrote:
>> [ EXTERNAL EMAIL ]
>>
>> On 06.06.2023 22:51, Arseniy Krasnov wrote:
>>> If there is no wired ready/busy pin, classic way to wait for command
>>> completion is to use function 'nand_soft_waitrdy()'. Meson NAND has
>>> special command which allows to wait for NAND_STATUS_READY bit without
>>> reading status in a software loop (as 'nand_soft_waitrdy()' does). To
>>> use it send this command along with NAND_CMD_STATUS, then wait for an
>>> interrupt, and after interrupt send NAND_CMD_READ0. So this feature
>>> allows to use interrupt driven waiting without wired ready/busy pin.
>>>
>>> Suggested-by: Liang Yang <liang.yang@...ogic.com>
>>> Signed-off-by: Arseniy Krasnov <AVKrasnov@...rdevices.ru>
>>> ---
>>> drivers/mtd/nand/raw/meson_nand.c | 58 ++++++++++++++++++++++++++++++-
>>> 1 file changed, 57 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
>>> index 074e14225c06..f4c5309a9527 100644
>>> --- a/drivers/mtd/nand/raw/meson_nand.c
>>> +++ b/drivers/mtd/nand/raw/meson_nand.c
>>> @@ -38,6 +38,7 @@
>>> #define NFC_CMD_SCRAMBLER_DISABLE 0
>>> #define NFC_CMD_SHORTMODE_DISABLE 0
>>> #define NFC_CMD_RB_INT BIT(14)
>>> +#define NFC_CMD_RB_INT_NO_PIN ((0xb << 10) | BIT(18) | BIT(16))
>>>
>>> #define NFC_CMD_GET_SIZE(x) (((x) >> 22) & GENMASK(4, 0))
>>>
>>> @@ -94,6 +95,7 @@
>>>
>>> /* nand flash controller delay 3 ns */
>>> #define NFC_DEFAULT_DELAY 3000
>>> +#define NFC_NO_RB_PIN_DELAY 5
>>>
>>> #define ROW_ADDER(page, index) (((page) >> (8 * (index))) & 0xff)
>>> #define MAX_CYCLE_ADDRS 5
>>> @@ -179,6 +181,7 @@ struct meson_nfc {
>>> u32 info_bytes;
>>>
>>> unsigned long assigned_cs;
>>> + bool no_rb_pin;
>>> };
>>>
>>> enum {
>>> @@ -392,7 +395,41 @@ static void meson_nfc_set_data_oob(struct nand_chip *nand,
>>> }
>>> }
>>>
>>> -static int meson_nfc_queue_rb(struct meson_nfc *nfc, int timeout_ms)
>>> +static int meson_nfc_wait_no_rb_pin(struct meson_nfc *nfc, int timeout_ms)
>>> +{
>>> + u32 cmd, cfg;
>>> +
>>> + meson_nfc_cmd_idle(nfc, nfc->timing.twb);
>>> + meson_nfc_drain_cmd(nfc);
>>> + meson_nfc_wait_cmd_finish(nfc, CMD_FIFO_EMPTY_TIMEOUT);
>>> +
>>> + cfg = readl(nfc->reg_base + NFC_REG_CFG);
>>> + cfg |= NFC_RB_IRQ_EN;
>>> + writel(cfg, nfc->reg_base + NFC_REG_CFG);
>>> +
>>> + reinit_completion(&nfc->completion);
>>> + cmd = nfc->param.chip_select | NFC_CMD_CLE | NAND_CMD_STATUS;
>>> + writel(cmd, nfc->reg_base + NFC_REG_CMD);
>>> + meson_nfc_cmd_idle(nfc, NFC_NO_RB_PIN_DELAY);
>>
>> ^^^
>>
>>> +
>>> + /* use the max erase time as the maximum clock for waiting R/B */
>>> + cmd = NFC_CMD_RB | NFC_CMD_RB_INT_NO_PIN | nfc->timing.tbers_max;
>>> + writel(cmd, nfc->reg_base + NFC_REG_CMD);
>>> + meson_nfc_cmd_idle(nfc, NFC_NO_RB_PIN_DELAY);
>>
>> ^^^
>> Liang, I've implemented "new RB_INT" way instead of 'nand_soft_waitrdy()'. There were two numbers
>> 2 and 5 in 'meson_nfc_cmd_idle()' as time argument (here and above). I've replaced both with
>> define of 5 == NFC_NO_RB_PIN_DELAY. Is it correct? 2 and 5 were from doc?
>
> You can do like that. as i know, bigger has no impact.
> yes, them come from the example code of the controller datasheet; but i think we can delete them also.
Done, removed in v2.
Thanks, Arseniy
>
>>
>> Thanks, Arseniy
>>
>>> +
>>> + if (!wait_for_completion_timeout(&nfc->completion,
>>> + msecs_to_jiffies(timeout_ms)))
>>> + return -ETIMEDOUT;
>>> +
>>> + cmd = nfc->param.chip_select | NFC_CMD_CLE | NAND_CMD_READ0;
>>> + writel(cmd, nfc->reg_base + NFC_REG_CMD);
>>> + meson_nfc_drain_cmd(nfc);
>>> + meson_nfc_wait_cmd_finish(nfc, CMD_FIFO_EMPTY_TIMEOUT);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int meson_nfc_wait_rb_pin(struct meson_nfc *nfc, int timeout_ms)
>>> {
>>> u32 cmd, cfg;
>>> int ret = 0;
>>> @@ -420,6 +457,23 @@ static int meson_nfc_queue_rb(struct meson_nfc *nfc, int timeout_ms)
>>> return ret;
>>> }
>>>
>>> +static int meson_nfc_queue_rb(struct meson_nfc *nfc, int timeout_ms)
>>> +{
>>> + if (nfc->no_rb_pin) {
>>> + /* This mode is used when there is no wired R/B pin.
>>> + * It works like 'nand_soft_waitrdy()', but instead of
>>> + * polling NAND_CMD_STATUS bit in the software loop,
>>> + * it will wait for interrupt - controllers checks IO
>>> + * bus and when it detects NAND_CMD_STATUS on it, it
>>> + * raises interrupt. After interrupt, NAND_CMD_READ0 is
>>> + * sent as terminator of the ready waiting procedure.
>>> + */
>>> + return meson_nfc_wait_no_rb_pin(nfc, timeout_ms);
>>> + } else {
>>> + return meson_nfc_wait_rb_pin(nfc, timeout_ms);
>>> + }
>>> +}
>>> +
>>> static void meson_nfc_set_user_byte(struct nand_chip *nand, u8 *oob_buf)
>>> {
>>> struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
>>> @@ -1412,6 +1466,8 @@ static int meson_nfc_probe(struct platform_device *pdev)
>>> return ret;
>>> }
>>>
>>> + nfc->no_rb_pin = !of_property_read_bool(dev->of_node, "nand-rb");
>>> +
>>> writel(0, nfc->reg_base + NFC_REG_CFG);
>>> ret = devm_request_irq(dev, irq, meson_nfc_irq, 0, dev_name(dev), nfc);
>>> if (ret) {
Powered by blists - more mailing lists