[PATCH v4 0/2] staging: mt7621-mmc: correctness fixes

[PATCH v4 0/2] staging: mt7621-mmc: correctness fixes

[George Hilliard]

Coding style fixup and rebase of v3, and resubmit of the Kconfig patch
that got dropped from v2.  No other changes.

Thanks for your continued attention and reviews!

George

[PATCH v4 1/2] staging: mt7621-mmc: Remove obsolete Kconfig flags

[George Hilliard]

These values are not referred to anywhere else in the kernel. Card
detect is controlled by the device tree property "mediatek,cd-poll",
and there is no driver support for eMMC whatsoever.

Signed-off-by: George Hilliard <thirtythreeforty@gmail.com>
---
v2: Rewrite of v1
v3: [Not present]
v4: Resubmit of v2

 drivers/staging/mt7621-mmc/Kconfig | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/drivers/staging/mt7621-mmc/Kconfig b/drivers/staging/mt7621-mmc/Kconfig
index 1eb79cd6e22f..01f231dd8511 100644
--- a/drivers/staging/mt7621-mmc/Kconfig
+++ b/drivers/staging/mt7621-mmc/Kconfig
@@ -6,11 +6,3 @@ config MTK_AEE_KDUMP
 	bool "MTK AEE KDUMP"
 	depends on MTK_MMC
 
-config MTK_MMC_CD_POLL
-	bool "Card Detect with Polling"
-	depends on MTK_MMC
-
-config MTK_MMC_EMMC_8BIT
-	bool "eMMC 8-bit support"
-	depends on MTK_MMC && RALINK_MT7628
-
-- 
2.21.0

[PATCH v4 2/2] staging: mt7621-mmc: Initialize completions a single time during probe

[George Hilliard]

The module was initializing completions whenever it was going to wait on
them, and not when the completion was allocated.  This is incorrect
according to the completion docs:

    Calling init_completion() on the same completion object twice is
    most likely a bug [...]

Re-initialization is also unnecessary because the module never uses
complete_all().  Fix this by only ever initializing the completion a
single time, and log if the completions are not consumed as intended
(this is not a fatal problem, but should not go unnoticed).

Signed-off-by: George Hilliard <thirtythreeforty@gmail.com>
---
v2: rewrite of v1
v3: Remove BUG_ON() calls
v4: Indent style fixup

 drivers/staging/mt7621-mmc/sd.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/mt7621-mmc/sd.c b/drivers/staging/mt7621-mmc/sd.c
index e346167754bd..ed63bd3ba6cc 100644
--- a/drivers/staging/mt7621-mmc/sd.c
+++ b/drivers/staging/mt7621-mmc/sd.c
@@ -466,7 +466,11 @@ static unsigned int msdc_command_start(struct msdc_host   *host,
 	host->cmd     = cmd;
 	host->cmd_rsp = resp;
 
-	init_completion(&host->cmd_done);
+	// The completion should have been consumed by the previous command
+	// response handler, because the mmc requests should be serialized
+	if(completion_done(&host->cmd_done))
+		dev_err(mmc_dev(host->mmc),
+		        "previous command was not handled\n");
 
 	sdr_set_bits(host->base + MSDC_INTEN, wints);
 	sdc_send_cmd(rawcmd, cmd->arg);
@@ -488,7 +492,6 @@ static unsigned int msdc_command_resp(struct msdc_host   *host,
 		    MSDC_INT_ACMD19_DONE;
 
 	BUG_ON(in_interrupt());
-	//init_completion(&host->cmd_done);
 	//sdr_set_bits(host->base + MSDC_INTEN, wints);
 
 	spin_unlock(&host->lock);
@@ -670,7 +673,13 @@ static int msdc_do_request(struct mmc_host *mmc, struct mmc_request *mrq)
 		//msdc_clr_fifo(host);  /* no need */
 
 		msdc_dma_on();  /* enable DMA mode first!! */
-		init_completion(&host->xfer_done);
+
+		// The completion should have been consumed by the previous
+		// xfer response handler, because the mmc requests should be
+		// serialized
+		if(completion_done(&host->cmd_done))
+			dev_err(mmc_dev(host->mmc),
+			        "previous transfer was not handled\n");
 
 		/* start the command first*/
 		if (msdc_command_start(host, cmd, CMD_TIMEOUT) != 0)
@@ -696,7 +705,6 @@ static int msdc_do_request(struct mmc_host *mmc, struct mmc_request *mrq)
 		/* for read, the data coming too fast, then CRC error
 		 *  start DMA no business with CRC.
 		 */
-		//init_completion(&host->xfer_done);
 		msdc_dma_start(host);
 
 		spin_unlock(&host->lock);
@@ -1687,6 +1695,8 @@ static int msdc_drv_probe(struct platform_device *pdev)
 	}
 	msdc_init_gpd_bd(host, &host->dma);
 
+	init_completion(&host->cmd_done);
+	init_completion(&host->xfer_done);
 	INIT_DELAYED_WORK(&host->card_delaywork, msdc_tasklet_card);
 	spin_lock_init(&host->lock);
 	msdc_init_hw(host);
-- 
2.21.0

Re: [PATCH v4 2/2] staging: mt7621-mmc: Initialize completions a single time during probe

[Greg Kroah-Hartman]

On Tue, Mar 26, 2019 at 09:21:39AM -0600, George Hilliard wrote:
> The module was initializing completions whenever it was going to wait on
> them, and not when the completion was allocated.  This is incorrect
> according to the completion docs:
> 
>     Calling init_completion() on the same completion object twice is
>     most likely a bug [...]
> 
> Re-initialization is also unnecessary because the module never uses
> complete_all().  Fix this by only ever initializing the completion a
> single time, and log if the completions are not consumed as intended
> (this is not a fatal problem, but should not go unnoticed).
> 
> Signed-off-by: George Hilliard <thirtythreeforty@gmail.com>
> ---
> v2: rewrite of v1
> v3: Remove BUG_ON() calls
> v4: Indent style fixup
> 
>  drivers/staging/mt7621-mmc/sd.c | 18 ++++++++++++++----
>  1 file changed, 14 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/staging/mt7621-mmc/sd.c b/drivers/staging/mt7621-mmc/sd.c
> index e346167754bd..ed63bd3ba6cc 100644
> --- a/drivers/staging/mt7621-mmc/sd.c
> +++ b/drivers/staging/mt7621-mmc/sd.c
> @@ -466,7 +466,11 @@ static unsigned int msdc_command_start(struct msdc_host   *host,
>  	host->cmd     = cmd;
>  	host->cmd_rsp = resp;
>  
> -	init_completion(&host->cmd_done);
> +	// The completion should have been consumed by the previous command
> +	// response handler, because the mmc requests should be serialized
> +	if(completion_done(&host->cmd_done))

Did you run your patch through checkpatch.pl?  It should have reported
an error here :(

Re: [PATCH v4 2/2] staging: mt7621-mmc: Initialize completions a single time during probe

[George Hilliard]

On Tue, Mar 26, 2019 at 6:46 PM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Tue, Mar 26, 2019 at 09:21:39AM -0600, George Hilliard wrote:
> > -     init_completion(&host->cmd_done);
> > +     // The completion should have been consumed by the previous command
> > +     // response handler, because the mmc requests should be serialized
> > +     if(completion_done(&host->cmd_done))
>
> Did you run your patch through checkpatch.pl?  It should have reported
> an error here :(

No, I didn't.  My mistake, sorry.  Will fix up and resend again.

George