Re: [U-Boot] [PATCH] mmc: fix OCR Polling
Hi Peng,
From: Peng.Fan at freescale.com (Peng Fan) Date: Thu, 19 Mar 2015 16:22:46 +0800 Subject: [U-Boot] [PATCH] mmc: fix OCR Polling
If in mmc_send_op_cond, OCR_BUSY is set in CMD1's response, then state is transfered to Ready state, and there is no need to send CMD1 again. Otherwise following CMD1 will recieve no response, or timeour error from driver such as fsl_esdhc.c.
If not into Ready state in previous CMD1, then continue CMD1 command.
In mmc_complete_op_cond, we use the value mmc->op_cond_response from mmc_send_op_cond, since there should be no CMD1 command between mmc_send_op_cond and mmc_complete_op_cond
Before fixing this, uboot log shows: " CMD_SEND:0 ARG 0x00000000 MMC_RSP_NONE CMD_SEND:8 ARG 0x000001AA MMC_RSP_R1,5,6,7 0x18EC1504 CMD_SEND:55 ARG 0x00000000 MMC_RSP_R1,5,6,7 0x18EC1504 CMD_SEND:0 ARG 0x00000000 MMC_RSP_NONE CMD_SEND:1 ARG 0x00000000 MMC_RSP_R3,4 0x00FF8080 CMD_SEND:1 ARG 0x40300000 MMC_RSP_R3,4 0xC0FF8080 --> Already OCR_BUSY
set
CMD_SEND:1 ARG 0x40300000 MMC_RSP_R3,4 0x0096850A --> Failed CMD1 MMC init failed "
Using this patch, this issue is fixed, emmc can be detected correctly.
Signed-off-by: Peng Fan <Peng.Fan at freescale.com>
drivers/mmc/mmc.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c index a13769e..43a9a8a 100644 --- a/drivers/mmc/mmc.c +++ b/drivers/mmc/mmc.c @@ -406,14 +406,23 @@ static int mmc_complete_op_cond(struct mmc *mmc)
mmc->op_cond_pending = 0; start = get_timer(0);
- do {
- /*
* If in mmc_send_op_cond, OCR_BUSY is set in CMD1's response, then* state is transfered to Ready state, and there is no need to* send CMD1 again. Otherwise following CMD1 will recieve no
response,
* or timeour error from driver such as fsl_esdhc.c.** If not into Ready state in previous CMD1, then continue CMD1* command.*/- while (!(mmc->op_cond_response & OCR_BUSY)) { err = mmc_send_op_cond_iter(mmc, &cmd, 1); if (err) return err; if (get_timer(start) > timeout) return UNUSABLE_ERR; udelay(100);
- } while (!(mmc->op_cond_response & OCR_BUSY));
}
if (mmc_host_is_spi(mmc)) { /* read OCR for spi */ cmd.cmdidx = MMC_CMD_SPI_READ_OCR;
-- 1.8.4
After this patch, if the busy flag is indeed already set (so that the loop body is not executed), and it is not an SPI case (mmc_host_is_spi(mmc) is false), the "cmd" structure (which is local to mmc_complete_op_cond() function) is left uninitialized, and using cmd.response[0] later in the function becomes incorrect. And the OCR register value and the high capacity flag may be set incorrectly.
So, this patch is not enough by itself, it needs to be modified (appended) in order to get the correct code.
Coincidentally, the same day I submitted a patch series ("[U-Boot] [PATCH 0/6] mmc: Fix OCR polling and splitted initialization"), that, among other changes, fixes the OCR polling problem too ("[U-Boot] [PATCH 4/6] mmc: Continue polling MMC card for OCR only if it is still not ready"), but in a slightly different way, that hopefully doesn't have the mentioned issue.
Thanks.
Best regards, Andrew
Hi, Andrew
On 3/20/2015 3:19 PM, Andrew Gabbasov wrote:
Hi Peng,
From: Peng.Fan at freescale.com (Peng Fan) Date: Thu, 19 Mar 2015 16:22:46 +0800 Subject: [U-Boot] [PATCH] mmc: fix OCR Polling
If in mmc_send_op_cond, OCR_BUSY is set in CMD1's response, then state is transfered to Ready state, and there is no need to send CMD1 again. Otherwise following CMD1 will recieve no response, or timeour error from driver such as fsl_esdhc.c.
If not into Ready state in previous CMD1, then continue CMD1 command.
In mmc_complete_op_cond, we use the value mmc->op_cond_response from mmc_send_op_cond, since there should be no CMD1 command between mmc_send_op_cond and mmc_complete_op_cond
Before fixing this, uboot log shows: " CMD_SEND:0 ARG 0x00000000 MMC_RSP_NONE CMD_SEND:8 ARG 0x000001AA MMC_RSP_R1,5,6,7 0x18EC1504 CMD_SEND:55 ARG 0x00000000 MMC_RSP_R1,5,6,7 0x18EC1504 CMD_SEND:0 ARG 0x00000000 MMC_RSP_NONE CMD_SEND:1 ARG 0x00000000 MMC_RSP_R3,4 0x00FF8080 CMD_SEND:1 ARG 0x40300000 MMC_RSP_R3,4 0xC0FF8080 --> Already OCR_BUSY
set
CMD_SEND:1 ARG 0x40300000 MMC_RSP_R3,4 0x0096850A --> Failed CMD1 MMC init failed "
Using this patch, this issue is fixed, emmc can be detected correctly.
Signed-off-by: Peng Fan <Peng.Fan at freescale.com>
drivers/mmc/mmc.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c index a13769e..43a9a8a 100644 --- a/drivers/mmc/mmc.c +++ b/drivers/mmc/mmc.c @@ -406,14 +406,23 @@ static int mmc_complete_op_cond(struct mmc *mmc)
mmc->op_cond_pending = 0; start = get_timer(0);
- do {
- /*
* If in mmc_send_op_cond, OCR_BUSY is set in CMD1's response, then* state is transfered to Ready state, and there is no need to* send CMD1 again. Otherwise following CMD1 will recieve noresponse,
* or timeour error from driver such as fsl_esdhc.c.** If not into Ready state in previous CMD1, then continue CMD1* command.*/- while (!(mmc->op_cond_response & OCR_BUSY)) { err = mmc_send_op_cond_iter(mmc, &cmd, 1); if (err) return err; if (get_timer(start) > timeout) return UNUSABLE_ERR; udelay(100);
- } while (!(mmc->op_cond_response & OCR_BUSY));
}
if (mmc_host_is_spi(mmc)) { /* read OCR for spi */ cmd.cmdidx = MMC_CMD_SPI_READ_OCR;
-- 1.8.4
After this patch, if the busy flag is indeed already set (so that the loop body is not executed), and it is not an SPI case (mmc_host_is_spi(mmc) is false), the "cmd" structure (which is local to mmc_complete_op_cond() function) is left uninitialized, and using cmd.response[0] later in the function becomes incorrect. And the OCR register value and the high capacity flag may be set incorrectly.
Yeah. you are right. Maybe the following piece of code should be added to replace mmc->ocr = cmd.response[0]: " if (mmc_host_is_spi(mmc)) mmc->ocr = cmd.response[0]; else mmc->ocr = mmc->op_cond_response; " Thanks for correcting me.
So, this patch is not enough by itself, it needs to be modified (appended) in order to get the correct code.
Coincidentally, the same day I submitted a patch series ("[U-Boot] [PATCH 0/6] mmc: Fix OCR polling and splitted initialization"), that, among other changes, fixes the OCR polling problem too ("[U-Boot] [PATCH 4/6] mmc: Continue polling MMC card for OCR only if it is still not ready"), but in a slightly different way, that hopefully doesn't have the mentioned issue.
Your's does not have such issue:)
Thanks.
Best regards, Andrew
.
Thanks Peng.
Hi Peng,
From: Peng Fan [mailto:Peng.Fan@freescale.com] Sent: Saturday, March 21, 2015 1:34 PM To: Gabbasov, Andrew; u-boot@lists.denx.de Subject: Re: [U-Boot] [PATCH] mmc: fix OCR Polling
[skipped]
After this patch, if the busy flag is indeed already set (so that the loop body is not executed), and it is not an SPI case (mmc_host_is_spi(mmc) is false), the "cmd" structure (which is local to mmc_complete_op_cond() function) is left uninitialized, and using cmd.response[0] later in the function becomes incorrect. And the OCR register value and the high capacity flag may be set incorrectly.
Yeah. you are right. Maybe the following piece of code should be added to replace mmc->ocr = cmd.response[0]: " if (mmc_host_is_spi(mmc)) mmc->ocr = cmd.response[0]; else mmc->ocr = mmc->op_cond_response; " Thanks for correcting me.
Well, there can be several ways to correct that. The easiest would be something similar to what you propose, but, just to avoid extra "if", we could add mmc->op_cond_response = cmd.response[0]; to the end of existing "if(mmc_host_is_spi(mmc))" and change mmc->ocr = cmd.response[0]; to mmc->ocr = mmc->op_cond_response; at the end of function. Since op_cond_response should be already set from the function beginning, this can be used immediately.
And, going further, since op_cond_response is actually the same contents as mmc->ocr, we could combine them and use mmc->ocr at once, from the beginning of polling loops. This is a little more complex, but makes the code cleaner. This is what is done in one of other patches in my series ;-)
Thanks.
Best regards, Andrew
Hi Andrew, Peng,
On Mar 23, 2015, at 01:23 , Andrew Gabbasov andrew_gabbasov@mentor.com wrote:
Hi Peng,
From: Peng Fan [mailto:Peng.Fan@freescale.com] Sent: Saturday, March 21, 2015 1:34 PM To: Gabbasov, Andrew; u-boot@lists.denx.de Subject: Re: [U-Boot] [PATCH] mmc: fix OCR Polling
[skipped]
After this patch, if the busy flag is indeed already set (so that the loop body is not executed), and it is not an SPI case (mmc_host_is_spi(mmc) is false), the "cmd" structure (which is local to mmc_complete_op_cond() function) is left uninitialized, and using cmd.response[0] later in the function becomes incorrect. And the OCR register value and the high capacity flag may be set incorrectly.
Yeah. you are right. Maybe the following piece of code should be added to replace mmc->ocr = cmd.response[0]: " if (mmc_host_is_spi(mmc)) mmc->ocr = cmd.response[0]; else mmc->ocr = mmc->op_cond_response; " Thanks for correcting me.
Well, there can be several ways to correct that. The easiest would be something similar to what you propose, but, just to avoid extra "if", we could add mmc->op_cond_response = cmd.response[0]; to the end of existing "if(mmc_host_is_spi(mmc))" and change mmc->ocr = cmd.response[0]; to mmc->ocr = mmc->op_cond_response; at the end of function. Since op_cond_response should be already set from the function beginning, this can be used immediately.
And, going further, since op_cond_response is actually the same contents as mmc->ocr, we could combine them and use mmc->ocr at once, from the beginning of polling loops. This is a little more complex, but makes the code cleaner. This is what is done in one of other patches in my series ;-)
This does seem like a case where a simple accessor structure would help until we figure out how to process.
Something like mmc_get_ocr() as a private API perhaps?
Thanks.
Best regards, Andrew
Regards
— Pantelis
U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Hi Pantelis,
From: Pantelis Antoniou [mailto:pantelis.antoniou@gmail.com] Sent: Friday, March 27, 2015 9:32 PM To: Gabbasov, Andrew Cc: Peng Fan; u-boot@lists.denx.de Subject: Re: [U-Boot] [PATCH] mmc: fix OCR Polling
Hi Andrew, Peng,
On Mar 23, 2015, at 01:23 , Andrew Gabbasov
andrew_gabbasov@mentor.com wrote:
Hi Peng,
From: Peng Fan [mailto:Peng.Fan@freescale.com] Sent: Saturday, March 21, 2015 1:34 PM To: Gabbasov, Andrew; u-boot@lists.denx.de Subject: Re: [U-Boot] [PATCH] mmc: fix OCR Polling
[skipped]
After this patch, if the busy flag is indeed already set (so that the loop body is not executed), and it is not an SPI case (mmc_host_is_spi(mmc) is false), the "cmd" structure (which is local to mmc_complete_op_cond() function) is left uninitialized, and using cmd.response[0] later in the function becomes incorrect. And the OCR register value and the high capacity flag may be set incorrectly.
Yeah. you are right. Maybe the following piece of code should be added to replace mmc->ocr = cmd.response[0]: " if (mmc_host_is_spi(mmc)) mmc->ocr = cmd.response[0]; else mmc->ocr = mmc->op_cond_response; " Thanks for correcting me.
Well, there can be several ways to correct that. The easiest would be something similar to what you propose, but, just to avoid extra "if", we could add mmc->op_cond_response = cmd.response[0]; to the end of existing "if(mmc_host_is_spi(mmc))" and change mmc->ocr = cmd.response[0]; to mmc->ocr = mmc->op_cond_response; at the end of function. Since op_cond_response should be already set from the function beginning, this can be used immediately.
And, going further, since op_cond_response is actually the same contents as mmc->ocr, we could combine them and use mmc->ocr at once, from the beginning of polling loops. This is a little more complex, but makes the code cleaner. This is what is done in one of other patches in my series ;-)
This does seem like a case where a simple accessor structure would help until we figure out how to process.
Something like mmc_get_ocr() as a private API perhaps?
Actually I don't see any need to introduce a new accessor or any other API here. Currently the 2 fields are used to store exactly the same data (OCR, which is a response to send_op_cond command). But the 'op_cond_response' is used while OCR polling and 'ocr' is filled in after its completion. The correct solution from my point of view is to just use a single field (ocr) from the very beginning. I have already submitted this solution in one of my patches ("[PATCH 2/6] mmc: Avoid extra duplicate entry in mmc device structure" in "[PATCH 0/6] mmc: Fix OCR polling and splitted initialization" series).
Thanks.
Best regards, Andrew
participants (3)
-
Andrew Gabbasov -
Pantelis Antoniou -
Peng Fan