Re: [PATCH v1 1/1] mmc: core: control EXT_CSD_CACHE_CTRL from device tree

From: Alex Lemberg
Date: Tue Dec 04 2018 - 11:26:37 EST



Hi,


ïOn 11/20/18, 10:07 PM, "linux-mmc-owner@xxxxxxxxxxxxxxx on behalf of Liming Sun" <linux-mmc-owner@xxxxxxxxxxxxxxx on behalf of lsun@xxxxxxxxxxxx> wrote:

Currently the EXT_CSD_CACHE_CTRL register is controlled by API
mmc_card_broken_hpi(), which only works for the quirks settings.
This commit enhances it to use card->ext_csd.hpi instead. This
flag works for both the quirks and the broken-hpi configuration
in the device tree.

Signed-off-by: Liming Sun <lsun@xxxxxxxxxxxx>
---
drivers/mmc/core/mmc.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index bc1bd2c..2f2b65c 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1791,8 +1791,7 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
* If cache size is higher than 0, this indicates
* the existence of cache and it can be turned on.
*/
- if (!mmc_card_broken_hpi(card) &&
- card->ext_csd.cache_size > 0) {
+ if (card->ext_csd.hpi && card->ext_csd.cache_size > 0) {


Any reason for making a connection between HPI and Cache
in current driver implementation?
BTW, I missed it before, but the previous commit making this connection -
is also doesn't make any sense.
Although by the spec FLUSH_CACHE is interruptible command, I don't think
we should prevent devices with no HPI support, using the Cache.
Please correct me if I wrong, but the current driver implementation allows
to send HPI for BKOPS and Sanitize (on timeout error) commands only -
so why we should limit the FLUSH_CACHE command?


err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
EXT_CSD_CACHE_CTRL, 1,
card->ext_csd.generic_cmd6_time);
--
1.8.3.1