lkml.org 
[lkml]   [2019]   [Mar]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 1/4] mmc: mmci: avoid fake busy polling
Date
From: Ludovic Barre <ludovic.barre@st.com>

The busy status bit could occurred even if no busy response is
expected (example cmd11). On sdmmc variant, the busy_detect_flag
reflects inverted value of d0 state, it's sampled at the end of a
CMD response and a second time 2 clk cycles after the CMD response.
To avoid a fake busy, the busy status could be checked and polled
only if the command has RSP_BUSY flag.

Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
---
drivers/mmc/host/mmci.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 387ff14..4901b73 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -1220,12 +1220,13 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd,
unsigned int status)
{
void __iomem *base = host->base;
- bool sbc;
+ bool sbc, busy_resp;

if (!cmd)
return;

sbc = (cmd == host->mrq->sbc);
+ busy_resp = !!(cmd->flags & MMC_RSP_BUSY);

/*
* We need to be one of these interrupts to be considered worth
@@ -1239,8 +1240,7 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd,
/*
* ST Micro variant: handle busy detection.
*/
- if (host->variant->busy_detect) {
- bool busy_resp = !!(cmd->flags & MMC_RSP_BUSY);
+ if (busy_resp && host->variant->busy_detect) {

/* We are busy with a command, return */
if (host->busy_status &&
@@ -1253,7 +1253,7 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd,
* that the special busy status bit is still set before
* proceeding.
*/
- if (!host->busy_status && busy_resp &&
+ if (!host->busy_status &&
!(status & (MCI_CMDCRCFAIL|MCI_CMDTIMEOUT)) &&
(readl(base + MMCISTATUS) & host->variant->busy_detect_flag)) {

@@ -1508,6 +1508,7 @@ static irqreturn_t mmci_irq(int irq, void *dev_id)
{
struct mmci_host *host = dev_id;
u32 status;
+ bool busy_resp;
int ret = 0;

spin_lock(&host->lock);
@@ -1550,9 +1551,15 @@ static irqreturn_t mmci_irq(int irq, void *dev_id)
}

/*
- * Don't poll for busy completion in irq context.
+ * Don't poll for:
+ * -busy completion in irq context.
+ * -no busy response expected.
*/
- if (host->variant->busy_detect && host->busy_status)
+ busy_resp = host->cmd ?
+ !!(host->cmd->flags & MMC_RSP_BUSY) : false;
+
+ if (host->variant->busy_detect &&
+ (!busy_resp || host->busy_status))
status &= ~host->variant->busy_detect_flag;

ret = 1;
--
2.7.4
\
 
 \ /
  Last update: 2019-03-05 17:11    [W:0.105 / U:6.076 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site