lkml.org 
[lkml]   [2018]   [Dec]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 1/4] mmc: meson-gx: make sure the descriptor is stopped on errors
Date
On errors, if we don't stop the descriptor chain, it may continue to
run and raise IRQ after we have called mmc_request_done(). This is bad
because we won't be able to get cmd anymore and properly deal with the
IRQ.

This patch makes sure the descriptor chain is stopped before
calling mmc_request_done()

Fixes: 79ed05e329c3 ("mmc: meson-gx: add support for descriptor chain mode")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
---
drivers/mmc/host/meson-gx-mmc.c | 73 ++++++++++++++++++++++++++++-----
1 file changed, 63 insertions(+), 10 deletions(-)

diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
index c201c378537e..fcb5d693c897 100644
--- a/drivers/mmc/host/meson-gx-mmc.c
+++ b/drivers/mmc/host/meson-gx-mmc.c
@@ -21,6 +21,7 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
+#include <linux/delay.h>
#include <linux/device.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
@@ -90,9 +91,11 @@
#define CFG_CLK_ALWAYS_ON BIT(18)
#define CFG_CHK_DS BIT(20)
#define CFG_AUTO_CLK BIT(23)
+#define CFG_ERR_ABORT BIT(27)

#define SD_EMMC_STATUS 0x48
#define STATUS_BUSY BIT(31)
+#define STATUS_DESC_BUSY BIT(30)
#define STATUS_DATI GENMASK(23, 16)

#define SD_EMMC_IRQ_EN 0x4c
@@ -928,6 +931,7 @@ static void meson_mmc_start_cmd(struct mmc_host *mmc, struct mmc_command *cmd)

cmd_cfg |= FIELD_PREP(CMD_CFG_CMD_INDEX_MASK, cmd->opcode);
cmd_cfg |= CMD_CFG_OWNER; /* owned by CPU */
+ cmd_cfg |= CMD_CFG_ERROR; /* stop in case of error */

meson_mmc_set_response_bits(cmd, &cmd_cfg);

@@ -1022,6 +1026,17 @@ static irqreturn_t meson_mmc_irq(int irq, void *dev_id)
u32 irq_en, status, raw_status;
irqreturn_t ret = IRQ_NONE;

+ irq_en = readl(host->regs + SD_EMMC_IRQ_EN);
+ raw_status = readl(host->regs + SD_EMMC_STATUS);
+ status = raw_status & irq_en;
+
+ if (!status) {
+ dev_dbg(host->dev,
+ "Unexpected IRQ! irq_en 0x%08x - status 0x%08x\n",
+ irq_en, raw_status);
+ return IRQ_NONE;
+ }
+
if (WARN_ON(!host) || WARN_ON(!host->cmd))
return IRQ_NONE;

@@ -1029,22 +1044,18 @@ static irqreturn_t meson_mmc_irq(int irq, void *dev_id)

cmd = host->cmd;
data = cmd->data;
- irq_en = readl(host->regs + SD_EMMC_IRQ_EN);
- raw_status = readl(host->regs + SD_EMMC_STATUS);
- status = raw_status & irq_en;
-
cmd->error = 0;
if (status & IRQ_CRC_ERR) {
dev_dbg(host->dev, "CRC Error - status 0x%08x\n", status);
cmd->error = -EILSEQ;
- ret = IRQ_HANDLED;
+ ret = IRQ_WAKE_THREAD;
goto out;
}

if (status & IRQ_TIMEOUTS) {
dev_dbg(host->dev, "Timeout - status 0x%08x\n", status);
cmd->error = -ETIMEDOUT;
- ret = IRQ_HANDLED;
+ ret = IRQ_WAKE_THREAD;
goto out;
}

@@ -1069,17 +1080,49 @@ static irqreturn_t meson_mmc_irq(int irq, void *dev_id)
/* ack all enabled interrupts */
writel(irq_en, host->regs + SD_EMMC_STATUS);

+ if (cmd->error) {
+ /* Stop desc in case of errors */
+ u32 start = readl(host->regs + SD_EMMC_START);
+
+ start &= ~START_DESC_BUSY;
+ writel(start, host->regs + SD_EMMC_START);
+ }
+
if (ret == IRQ_HANDLED)
meson_mmc_request_done(host->mmc, cmd->mrq);
- else if (ret == IRQ_NONE)
- dev_warn(host->dev,
- "Unexpected IRQ! status=0x%08x, irq_en=0x%08x\n",
- raw_status, irq_en);

spin_unlock(&host->lock);
return ret;
}

+static int meson_mmc_wait_desc_stop(struct meson_host *host)
+{
+ int loop;
+ u32 status;
+
+ /*
+ * It may sometimes take a while for it to actually halt. Here, we
+ * are giving it 5ms to comply
+ *
+ * If we don't confirm the descriptor is stopped, it might raise new
+ * IRQs after we have called mmc_request_done() which is bad.
+ */
+ for (loop = 50; loop; loop--) {
+ status = readl(host->regs + SD_EMMC_STATUS);
+ if (status & (STATUS_BUSY | STATUS_DESC_BUSY))
+ udelay(100);
+ else
+ break;
+ }
+
+ if (status & (STATUS_BUSY | STATUS_DESC_BUSY)) {
+ dev_err(host->dev, "Timed out waiting for host to stop\n");
+ return -ETIMEDOUT;
+ }
+
+ return 0;
+}
+
static irqreturn_t meson_mmc_irq_thread(int irq, void *dev_id)
{
struct meson_host *host = dev_id;
@@ -1090,6 +1133,13 @@ static irqreturn_t meson_mmc_irq_thread(int irq, void *dev_id)
if (WARN_ON(!cmd))
return IRQ_NONE;

+ if (cmd->error) {
+ meson_mmc_wait_desc_stop(host);
+ meson_mmc_request_done(host->mmc, cmd->mrq);
+
+ return IRQ_HANDLED;
+ }
+
data = cmd->data;
if (meson_mmc_bounce_buf_read(data)) {
xfer_bytes = data->blksz * data->blocks;
@@ -1130,6 +1180,9 @@ static void meson_mmc_cfg_init(struct meson_host *host)
cfg |= FIELD_PREP(CFG_RC_CC_MASK, ilog2(SD_EMMC_CFG_CMD_GAP));
cfg |= FIELD_PREP(CFG_BLK_LEN_MASK, ilog2(SD_EMMC_CFG_BLK_SIZE));

+ /* abort chain on R/W errors */
+ cfg |= CFG_ERR_ABORT;
+
writel(cfg, host->regs + SD_EMMC_CFG);
}

--
2.19.2
\
 
 \ /
  Last update: 2018-12-06 16:19    [W:0.074 / U:0.660 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site