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Message-ID: <20230607145026.2899547-3-AVKrasnov@sberdevices.ru>
Date: Wed, 7 Jun 2023 17:50:25 +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>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
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>,
Arseniy Krasnov <AVKrasnov@...rdevices.ru>,
<linux-mtd@...ts.infradead.org>, <devicetree@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-amlogic@...ts.infradead.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH v1 2/2] mtd: rawnand: meson: waiting w/o wired ready/busy pin
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 | 82 +++++++++++++++++++++++++++++--
1 file changed, 78 insertions(+), 4 deletions(-)
diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
index 074e14225c06..935de8e4934d 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))
@@ -179,6 +180,7 @@ struct meson_nfc {
u32 info_bytes;
unsigned long assigned_cs;
+ bool no_rb_pin;
};
enum {
@@ -392,7 +394,42 @@ 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,
+ bool need_cmd_read0)
+{
+ 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);
+
+ /* 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);
+
+ if (!wait_for_completion_timeout(&nfc->completion,
+ msecs_to_jiffies(timeout_ms)))
+ return -ETIMEDOUT;
+
+ if (need_cmd_read0) {
+ 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 +457,27 @@ 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,
+ bool need_cmd_read0)
+{
+ 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 if
+ * needed (for all cases except page programming - this
+ * is reason of 'need_cmd_read0' flag).
+ */
+ return meson_nfc_wait_no_rb_pin(nfc, timeout_ms,
+ need_cmd_read0);
+ } 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);
@@ -623,7 +681,7 @@ static int meson_nfc_rw_cmd_prepare_and_execute(struct nand_chip *nand,
if (in) {
nfc->cmdfifo.rw.cmd1 = cs | NFC_CMD_CLE | NAND_CMD_READSTART;
writel(nfc->cmdfifo.rw.cmd1, nfc->reg_base + NFC_REG_CMD);
- meson_nfc_queue_rb(nfc, PSEC_TO_MSEC(sdr->tR_max));
+ meson_nfc_queue_rb(nfc, PSEC_TO_MSEC(sdr->tR_max), true);
} else {
meson_nfc_cmd_idle(nfc, nfc->timing.tadl);
}
@@ -669,7 +727,7 @@ static int meson_nfc_write_page_sub(struct nand_chip *nand,
cmd = nfc->param.chip_select | NFC_CMD_CLE | NAND_CMD_PAGEPROG;
writel(cmd, nfc->reg_base + NFC_REG_CMD);
- meson_nfc_queue_rb(nfc, PSEC_TO_MSEC(sdr->tPROG_max));
+ meson_nfc_queue_rb(nfc, PSEC_TO_MSEC(sdr->tPROG_max), false);
meson_nfc_dma_buffer_release(nand, data_len, info_len, DMA_TO_DEVICE);
@@ -952,7 +1010,8 @@ static int meson_nfc_exec_op(struct nand_chip *nand,
break;
case NAND_OP_WAITRDY_INSTR:
- meson_nfc_queue_rb(nfc, instr->ctx.waitrdy.timeout_ms);
+ meson_nfc_queue_rb(nfc, instr->ctx.waitrdy.timeout_ms,
+ true);
if (instr->delay_ns)
meson_nfc_cmd_idle(nfc, delay_idle);
break;
@@ -1248,6 +1307,7 @@ meson_nfc_nand_chip_init(struct device *dev,
struct mtd_info *mtd;
int ret, i;
u32 tmp, nsels;
+ u32 nand_rb_val;
nsels = of_property_count_elems_of_size(np, "reg", sizeof(u32));
if (!nsels || nsels > MAX_CE_NUM) {
@@ -1287,6 +1347,20 @@ meson_nfc_nand_chip_init(struct device *dev,
mtd->owner = THIS_MODULE;
mtd->dev.parent = dev;
+ ret = of_property_read_u32(np, "nand-rb", &nand_rb_val);
+ if (ret) {
+ /* If property was not found, don't use rb pin. */
+ if (ret == -EINVAL)
+ nfc->no_rb_pin = true;
+ else
+ return -EINVAL;
+ } else {
+ if (nand_rb_val)
+ return -EINVAL;
+
+ nfc->no_rb_pin = false;
+ }
+
ret = nand_scan(nand, nsels);
if (ret)
return ret;
--
2.35.0
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