diff options
| author | Subhash Jadavani <subhashj@codeaurora.org> | 2014-09-02 18:02:57 -0700 |
|---|---|---|
| committer | Subhash Jadavani <subhashj@codeaurora.org> | 2016-05-31 15:28:16 -0700 |
| commit | 8cd010a89a5207965584aa1b716591ccc9c7f525 (patch) | |
| tree | f6653b1bb8e2a6a42c31fa812c816100c05376bd /drivers/mmc | |
| parent | d69edcbcaed2001b9c305a2b8668dc0599801f2a (diff) | |
mmc: host: sdhci: don't queue zero length descriptor
If zero length ADMA descriptor with "Tran" attribute is queued to ADMA
descriptor table then host controller ADMA engine might get stuck.
Currently we are seeing zero length descriptor getting queued in for
SDIO transactions:
SDHCi driver requires that any data buffer address should be 4-byte
aligned for 32-bit ADMA and 8-bytes aligned for 64-bit ADMA. For 64-bit
ADMA, it forces 8-byte alignment for any data buffer addresses. This
aligment requirement is not an issue with eMMC/SD cards as their
transactions are always in multiple of 512-bytes (block size) and hence
sdhci driver would always get the data buffers whose address is properly
aligned.
SDIO can have transactions less than 512-bytes. Hence its quite possible
for driver to receives data buffer addresses which are not properly
aligned. And if they are not aligned, SDHCi driver bounces the non-aligned
bytes to pre-allocated aligned buffer until the rest of the data buffer
becomes aligned. But this logic has a bug where after moving the
non-aligned number of bytes to aligned buffer, it assumes that we will
always be left with non-zero number of bytes in original data buffer and
hence driver ends up queuing one more descriptor which can be of zero
length.
Fix this by checking for the remaining data length before queuing up the
next descriptor.
Change-Id: I7af77b2a2661c00f2b1da47953717b1506bdba83
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
[subhashj@codeaurora.org: fixed merge conflicts]
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Diffstat (limited to 'drivers/mmc')
| -rw-r--r-- | drivers/mmc/host/sdhci.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 2b34aec58c2c..572555876643 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -626,9 +626,11 @@ static int sdhci_adma_table_pre(struct sdhci_host *host, BUG_ON(len > 65536); - /* tran, valid */ - sdhci_adma_write_desc(host, desc, addr, len, ADMA2_TRAN_VALID); - desc += host->desc_sz; + if (len) { + /* tran, valid */ + sdhci_adma_write_desc(host, desc, addr, len, ADMA2_TRAN_VALID); + desc += host->desc_sz; + } /* * If this triggers then we have a calculation bug |