[PATCH v2 3/7] mtd: spi-nor: Add support for panic writes
Paul Cercueil
paul.cercueil at bootlin.com
Tue Oct 13 07:13:46 PDT 2026
From: Tanmay Jagdale <tanmay at marvell.com>
If the SPI controller supports it, provide the functionality of doing a
panic write.
Update the spi-nor core code and controllers to make sure they won't try
to grab locked mutexes or sleep when doing a panic write, as preemption
and IRQs are disabled.
The information is carried down to the SPI controller driver through the
spi_mem_op structure. If the corresponding flag is set there, and the
SPI driver does support panic writes, it then has to respect the same
rules.
Signed-off-by: Tanmay Jagdale <tanmay at marvell.com>
Co-developed-by: Paul Cercueil <paul.cercueil at bootlin.com>
Signed-off-by: Paul Cercueil <paul.cercueil at bootlin.com>
---
Notes:
v2: - Update spi_nor_wait_till_ready_with_timeout() to use
poll_timeout_us_atomic() on panic
- Alloc temp buffer with GFP_ATOMIC in spi_nor_octal_dtr_write()
on panic
- Bail out if nor->rww.ongoing_pe is set in spi_nor_panic_write()
drivers/mtd/spi-nor/core.c | 78 +++++++++++++++++++++++++++++++++++---
1 file changed, 73 insertions(+), 5 deletions(-)
diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index 2509fb983d4f..281acc54b324 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -97,6 +97,9 @@ void spi_nor_spimem_setup_op(const struct spi_nor *nor,
if (op->data.nbytes)
op->data.buswidth = spi_nor_get_protocol_data_nbits(proto);
+ if (nor->mtd.oops_panic_write)
+ op->panic_write = true;
+
if (spi_nor_protocol_is_dtr(proto)) {
/*
* SPIMEM supports mixed DTR modes, but right now we can only
@@ -282,7 +285,7 @@ static ssize_t spi_nor_spimem_write_data(struct spi_nor *nor, loff_t to,
if (spi_nor_spimem_bounce(nor, &op))
memcpy(nor->bouncebuf, buf, op.data.nbytes);
- if (nor->dirmap.wdesc) {
+ if (nor->dirmap.wdesc && !nor->mtd.oops_panic_write) {
nbytes = spi_mem_dirmap_write(nor->dirmap.wdesc, op.addr.val,
op.data.nbytes, op.data.buf.out);
} else {
@@ -665,6 +668,9 @@ static void spi_nor_rww_end_rdst(struct spi_nor *nor)
static int spi_nor_lock_rdst(struct spi_nor *nor)
{
+ if (nor->mtd.oops_panic_write)
+ return 0;
+
if (spi_nor_use_parallel_locking(nor))
return spi_nor_rww_start_rdst(nor);
@@ -673,6 +679,9 @@ static int spi_nor_lock_rdst(struct spi_nor *nor)
static void spi_nor_unlock_rdst(struct spi_nor *nor)
{
+ if (nor->mtd.oops_panic_write)
+ return;
+
if (spi_nor_use_parallel_locking(nor)) {
spi_nor_rww_end_rdst(nor);
wake_up(&nor->rww.wait);
@@ -717,8 +726,14 @@ static int spi_nor_wait_till_ready_with_timeout(struct spi_nor *nor,
{
int ret, status;
- ret = poll_timeout_us(status = spi_nor_ready(nor), status,
- 100, timeout_ms * 1000, false);
+ if (nor->mtd.oops_panic_write) {
+ ret = poll_timeout_us_atomic(status = spi_nor_ready(nor), status,
+ 100, timeout_ms * 1000, false);
+ } else {
+ ret = poll_timeout_us(status = spi_nor_ready(nor), status,
+ 100, timeout_ms * 1000, false);
+ }
+
if (ret < 0) {
dev_dbg(nor->dev, "flash operation timed out\n");
return ret;
@@ -1284,6 +1299,9 @@ static void spi_nor_rww_end_io(struct spi_nor *nor)
static int spi_nor_lock_device(struct spi_nor *nor)
{
+ if (nor->mtd.oops_panic_write)
+ return 0;
+
if (!spi_nor_use_parallel_locking(nor))
return 0;
@@ -1292,6 +1310,9 @@ static int spi_nor_lock_device(struct spi_nor *nor)
static void spi_nor_unlock_device(struct spi_nor *nor)
{
+ if (nor->mtd.oops_panic_write)
+ return;
+
if (spi_nor_use_parallel_locking(nor)) {
spi_nor_rww_end_io(nor);
wake_up(&nor->rww.wait);
@@ -1329,6 +1350,9 @@ int spi_nor_prep_and_lock(struct spi_nor *nor)
{
int ret;
+ if (nor->mtd.oops_panic_write)
+ return 0;
+
ret = spi_nor_prep(nor);
if (ret)
return ret;
@@ -1344,6 +1368,9 @@ int spi_nor_prep_and_lock(struct spi_nor *nor)
void spi_nor_unlock_and_unprep(struct spi_nor *nor)
{
+ if (nor->mtd.oops_panic_write)
+ return;
+
if (!spi_nor_use_parallel_locking(nor)) {
mutex_unlock(&nor->lock);
} else {
@@ -1400,6 +1427,9 @@ static int spi_nor_prep_and_lock_pe(struct spi_nor *nor, loff_t start, size_t le
{
int ret;
+ if (nor->mtd.oops_panic_write)
+ return 0;
+
ret = spi_nor_prep(nor);
if (ret)
return ret;
@@ -1415,6 +1445,9 @@ static int spi_nor_prep_and_lock_pe(struct spi_nor *nor, loff_t start, size_t le
static void spi_nor_unlock_and_unprep_pe(struct spi_nor *nor, loff_t start, size_t len)
{
+ if (nor->mtd.oops_panic_write)
+ return;
+
if (!spi_nor_use_parallel_locking(nor)) {
mutex_unlock(&nor->lock);
} else {
@@ -1473,6 +1506,9 @@ static int spi_nor_prep_and_lock_rd(struct spi_nor *nor, loff_t start, size_t le
{
int ret;
+ if (nor->mtd.oops_panic_write)
+ return 0;
+
ret = spi_nor_prep(nor);
if (ret)
return ret;
@@ -1488,6 +1524,9 @@ static int spi_nor_prep_and_lock_rd(struct spi_nor *nor, loff_t start, size_t le
static void spi_nor_unlock_and_unprep_rd(struct spi_nor *nor, loff_t start, size_t len)
{
+ if (nor->mtd.oops_panic_write)
+ return;
+
if (!spi_nor_use_parallel_locking(nor)) {
mutex_unlock(&nor->lock);
} else {
@@ -2196,6 +2235,7 @@ static int spi_nor_read(struct mtd_info *mtd, loff_t from, size_t len,
static int spi_nor_octal_dtr_write(struct spi_nor *nor, loff_t to, size_t len,
const u8 *buf)
{
+ gfp_t mm_flags = GFP_KERNEL;
u8 *tmp_buf;
size_t bytes_written;
loff_t start, end;
@@ -2204,7 +2244,10 @@ static int spi_nor_octal_dtr_write(struct spi_nor *nor, loff_t to, size_t len,
if (IS_ALIGNED(to, 2) && IS_ALIGNED(len, 2))
return spi_nor_write_data(nor, to, len, buf);
- tmp_buf = kmalloc(nor->params->page_size, GFP_KERNEL);
+ if (nor->mtd.oops_panic_write)
+ mm_flags |= GFP_ATOMIC;
+
+ tmp_buf = kmalloc(nor->params->page_size, mm_flags);
if (!tmp_buf)
return -ENOMEM;
@@ -3386,6 +3429,26 @@ static void spi_nor_soft_reset(struct spi_nor *nor)
usleep_range(SPI_NOR_SRST_SLEEP_MIN, SPI_NOR_SRST_SLEEP_MAX);
}
+static int spi_nor_panic_write(struct mtd_info *mtd, loff_t to, size_t len,
+ size_t *retlen, const u_char *buf)
+{
+ struct spi_nor *nor = mtd_to_spi_nor(mtd);
+
+ /*
+ * At this point preemption and local interrupts are disabled, so we
+ * can't get the lock if it's taken.
+ */
+ if (mutex_is_locked(&nor->lock))
+ return -EPERM;
+
+ if (spi_nor_use_parallel_locking(nor) &&
+ (nor->rww.ongoing_io || nor->rww.ongoing_rd || nor->rww.ongoing_pe)) {
+ return -EPERM;
+ }
+
+ return spi_nor_write(mtd, to, len, retlen, buf);
+}
+
/* mtd suspend handler */
static int spi_nor_suspend(struct mtd_info *mtd)
{
@@ -3589,8 +3652,13 @@ static int spi_nor_set_mtd_info(struct spi_nor *nor)
mtd->size = nor->params->size;
mtd->_read = spi_nor_read;
/* Might be already set by some SST flashes. */
- if (!mtd->_write)
+ if (!mtd->_write) {
mtd->_write = spi_nor_write;
+ if (nor->spimem &&
+ spi_mem_controller_is_capable(nor->spimem->spi->controller, panic_write)) {
+ mtd->_panic_write = spi_nor_panic_write;
+ }
+ }
mtd->_suspend = spi_nor_suspend;
mtd->_resume = spi_nor_resume;
mtd->_get_device = spi_nor_get_device;
--
2.47.3
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