4.19-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit a6a66f80c85e8e20573ca03fabf32445954a88d5 ]
The current Cadence QSPI driver caused a kernel panic sporadically when writing to QSPI. The problem was caused by writing more bytes than needed because the QSPI operated on 4 bytes at a time. <snip> [ 11.202044] Unable to handle kernel paging request at virtual address bffd3000 [ 11.209254] pgd = e463054d [ 11.211948] [bffd3000] *pgd=2fffb811, *pte=00000000, *ppte=00000000 [ 11.218202] Internal error: Oops: 7 [#1] SMP ARM [ 11.222797] Modules linked in: [ 11.225844] CPU: 1 PID: 1317 Comm: systemd-hwdb Not tainted 4.17.7-d0c45cd44a8f [ 11.235796] Hardware name: Altera SOCFPGA Arria10 [ 11.240487] PC is at __raw_writesl+0x70/0xd4 [ 11.244741] LR is at cqspi_write+0x1a0/0x2cc </snip> On a page boundary limit the number of bytes copied from the tx buffer to remain within the page.
This patch uses a temporary buffer to hold the 4 bytes to write and then copies only the bytes required from the tx buffer.
Reported-by: Adrian Amborzewicz adrian.ambrozewicz@intel.com Signed-off-by: Thor Thayer thor.thayer@linux.intel.com Signed-off-by: Boris Brezillon boris.brezillon@bootlin.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/mtd/spi-nor/cadence-quadspi.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-)
diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c b/drivers/mtd/spi-nor/cadence-quadspi.c index 6e9cbd1a0b6d..0806c7a81c0f 100644 --- a/drivers/mtd/spi-nor/cadence-quadspi.c +++ b/drivers/mtd/spi-nor/cadence-quadspi.c @@ -644,9 +644,23 @@ static int cqspi_indirect_write_execute(struct spi_nor *nor, loff_t to_addr, ndelay(cqspi->wr_delay);
while (remaining > 0) { + size_t write_words, mod_bytes; + write_bytes = remaining > page_size ? page_size : remaining; - iowrite32_rep(cqspi->ahb_base, txbuf, - DIV_ROUND_UP(write_bytes, 4)); + write_words = write_bytes / 4; + mod_bytes = write_bytes % 4; + /* Write 4 bytes at a time then single bytes. */ + if (write_words) { + iowrite32_rep(cqspi->ahb_base, txbuf, write_words); + txbuf += (write_words * 4); + } + if (mod_bytes) { + unsigned int temp = 0xFFFFFFFF; + + memcpy(&temp, txbuf, mod_bytes); + iowrite32(temp, cqspi->ahb_base); + txbuf += mod_bytes; + }
if (!wait_for_completion_timeout(&cqspi->transfer_complete, msecs_to_jiffies(CQSPI_TIMEOUT_MS))) { @@ -655,7 +669,6 @@ static int cqspi_indirect_write_execute(struct spi_nor *nor, loff_t to_addr, goto failwr; }
- txbuf += write_bytes; remaining -= write_bytes;
if (remaining > 0)