From d7dace92d0402d2c64d2486b93f8b655a87f33b2 Mon Sep 17 00:00:00 2001 From: Thor Thayer Date: Fri, 16 Nov 2018 08:25:49 -0600 Subject: [PATCH] mtd: spi-nor: Fix Cadence QSPI page fault kernel panic [ 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. [ 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 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 Signed-off-by: Thor Thayer Signed-off-by: Boris Brezillon Signed-off-by: Sasha Levin --- 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 6e9cbd1..0806c7a 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) -- 2.7.4