[PATCH v8 1/2] mmc: add packed command feature of eMMC4.5

[PATCH v8 1/2] mmc: add packed command feature of eMMC4.5

[Seungwon Jeon]

This patch adds packed command feature of eMMC4.5.
The maximum number for packing read(or write) is offered
and exception event relevant to packed command which is
used for error handling is enabled. If host wants to use
this feature, MMC_CAP2_PACKED_CMD should be set.

Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
Reviewed-by: Maya Erez <merez@codeaurora.org>
Reviewed-by: Subhash Jadavani <subhashj@codeaurora.org>
Reviewed-by: Namjae Jeon <linkinjeon@gmail.com>
---
 drivers/mmc/core/mmc.c   |   25 +++++++++++++++++++++++++
 include/linux/mmc/card.h |    3 +++
 include/linux/mmc/host.h |    4 ++++
 include/linux/mmc/mmc.h  |   15 +++++++++++++++
 4 files changed, 47 insertions(+), 0 deletions(-)

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 258b203..bfb271f 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -516,6 +516,11 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
 		} else {
 			card->ext_csd.data_tag_unit_size = 0;
 		}
+
+		card->ext_csd.max_packed_writes =
+			ext_csd[EXT_CSD_MAX_PACKED_WRITES];
+		card->ext_csd.max_packed_reads =
+			ext_csd[EXT_CSD_MAX_PACKED_READS];
 	} else {
 		card->ext_csd.data_sector_size = 512;
 	}
@@ -1246,6 +1251,26 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
 		}
 	}
 
+	if ((host->caps2 & MMC_CAP2_PACKED_WR &&
+			card->ext_csd.max_packed_writes > 0) ||
+	    (host->caps2 & MMC_CAP2_PACKED_RD &&
+			card->ext_csd.max_packed_reads > 0)) {
+		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+				EXT_CSD_EXP_EVENTS_CTRL,
+				EXT_CSD_PACKED_EVENT_EN,
+				card->ext_csd.generic_cmd6_time);
+		if (err && err != -EBADMSG)
+			goto free_card;
+		if (err) {
+			pr_warning("%s: Enabling packed event failed\n",
+					mmc_hostname(card->host));
+			card->ext_csd.packed_event_en = 0;
+			err = 0;
+		} else {
+			card->ext_csd.packed_event_en = 1;
+		}
+	}
+
 	if (!oldcard)
 		host->card = card;
 
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index d76513b..4aeb4e9 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -53,6 +53,9 @@ struct mmc_ext_csd {
 	u8			part_config;
 	u8			cache_ctrl;
 	u8			rst_n_function;
+	u8			max_packed_writes;
+	u8			max_packed_reads;
+	u8			packed_event_en;
 	unsigned int		part_time;		/* Units: ms */
 	unsigned int		sa_timeout;		/* Units: 100ns */
 	unsigned int		generic_cmd6_time;	/* Units: 10ms */
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 9deb725..bb19b98 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -245,6 +245,10 @@ struct mmc_host {
 #define MMC_CAP2_BROKEN_VOLTAGE	(1 << 7)	/* Use the broken voltage */
 #define MMC_CAP2_DETECT_ON_ERR	(1 << 8)	/* On I/O err check card removal */
 #define MMC_CAP2_HC_ERASE_SZ	(1 << 9)	/* High-capacity erase size */
+#define MMC_CAP2_PACKED_RD	(1 << 10)	/* Allow packed read */
+#define MMC_CAP2_PACKED_WR	(1 << 11)	/* Allow packed write */
+#define MMC_CAP2_PACKED_CMD	(MMC_CAP2_PACKED_RD | \
+				 MMC_CAP2_PACKED_WR) /* Allow packed commands */
 
 	mmc_pm_flag_t		pm_caps;	/* supported pm features */
 	unsigned int        power_notify_type;
diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
index d425cab..254901a 100644
--- a/include/linux/mmc/mmc.h
+++ b/include/linux/mmc/mmc.h
@@ -139,6 +139,7 @@ static inline bool mmc_op_multi(u32 opcode)
 #define R1_CURRENT_STATE(x)	((x & 0x00001E00) >> 9)	/* sx, b (4 bits) */
 #define R1_READY_FOR_DATA	(1 << 8)	/* sx, a */
 #define R1_SWITCH_ERROR		(1 << 7)	/* sx, c */
+#define R1_EXP_EVENT		(1 << 6)	/* sr, a */
 #define R1_APP_CMD		(1 << 5)	/* sr, c */
 
 #define R1_STATE_IDLE	0
@@ -274,6 +275,10 @@ struct _mmc_csd {
 #define EXT_CSD_FLUSH_CACHE		32      /* W */
 #define EXT_CSD_CACHE_CTRL		33      /* R/W */
 #define EXT_CSD_POWER_OFF_NOTIFICATION	34	/* R/W */
+#define EXT_CSD_PACKED_FAILURE_INDEX	35	/* RO */
+#define EXT_CSD_PACKED_CMD_STATUS	36	/* RO */
+#define EXT_CSD_EXP_EVENTS_STATUS	54	/* RO, 2 bytes */
+#define EXT_CSD_EXP_EVENTS_CTRL	56	/* R/W, 2 bytes */
 #define EXT_CSD_DATA_SECTOR_SIZE	61	/* R */
 #define EXT_CSD_GP_SIZE_MULT		143	/* R/W */
 #define EXT_CSD_PARTITION_ATTRIBUTE	156	/* R/W */
@@ -318,6 +323,8 @@ struct _mmc_csd {
 #define EXT_CSD_CACHE_SIZE		249	/* RO, 4 bytes */
 #define EXT_CSD_TAG_UNIT_SIZE		498	/* RO */
 #define EXT_CSD_DATA_TAG_SUPPORT	499	/* RO */
+#define EXT_CSD_MAX_PACKED_WRITES	500	/* RO */
+#define EXT_CSD_MAX_PACKED_READS	501	/* RO */
 #define EXT_CSD_HPI_FEATURES		503	/* RO */
 
 /*
@@ -377,6 +384,14 @@ struct _mmc_csd {
 #define EXT_CSD_PWR_CL_4BIT_MASK	0x0F	/* 8 bit PWR CLS */
 #define EXT_CSD_PWR_CL_8BIT_SHIFT	4
 #define EXT_CSD_PWR_CL_4BIT_SHIFT	0
+
+#define EXT_CSD_PACKED_EVENT_EN	(1 << 3)
+
+#define EXT_CSD_PACKED_FAILURE	(1 << 3)
+
+#define EXT_CSD_PACKED_GENERIC_ERROR	(1 << 0)
+#define EXT_CSD_PACKED_INDEXED_ERROR	(1 << 1)
+
 /*
  * MMC_SWITCH access modes
  */
-- 
1.7.0.4

Re: [PATCH v8 1/2] mmc: add packed command feature of eMMC4.5

[merez]

Hi Chris,

Can we push this change to mmc-next?

Thanks,
Maya
On Thu, June 28, 2012 9:32 pm, Seungwon Jeon wrote:
> This patch adds packed command feature of eMMC4.5.
> The maximum number for packing read(or write) is offered
> and exception event relevant to packed command which is
> used for error handling is enabled. If host wants to use
> this feature, MMC_CAP2_PACKED_CMD should be set.
>
> Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
> Reviewed-by: Maya Erez <merez@codeaurora.org>
> Reviewed-by: Subhash Jadavani <subhashj@codeaurora.org>
> Reviewed-by: Namjae Jeon <linkinjeon@gmail.com>
> ---
>  drivers/mmc/core/mmc.c   |   25 +++++++++++++++++++++++++
>  include/linux/mmc/card.h |    3 +++
>  include/linux/mmc/host.h |    4 ++++
>  include/linux/mmc/mmc.h  |   15 +++++++++++++++
>  4 files changed, 47 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 258b203..bfb271f 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -516,6 +516,11 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8
> *ext_csd)
>  		} else {
>  			card->ext_csd.data_tag_unit_size = 0;
>  		}
> +
> +		card->ext_csd.max_packed_writes =
> +			ext_csd[EXT_CSD_MAX_PACKED_WRITES];
> +		card->ext_csd.max_packed_reads =
> +			ext_csd[EXT_CSD_MAX_PACKED_READS];
>  	} else {
>  		card->ext_csd.data_sector_size = 512;
>  	}
> @@ -1246,6 +1251,26 @@ static int mmc_init_card(struct mmc_host *host, u32
> ocr,
>  		}
>  	}
>
> +	if ((host->caps2 & MMC_CAP2_PACKED_WR &&
> +			card->ext_csd.max_packed_writes > 0) ||
> +	    (host->caps2 & MMC_CAP2_PACKED_RD &&
> +			card->ext_csd.max_packed_reads > 0)) {
> +		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> +				EXT_CSD_EXP_EVENTS_CTRL,
> +				EXT_CSD_PACKED_EVENT_EN,
> +				card->ext_csd.generic_cmd6_time);
> +		if (err && err != -EBADMSG)
> +			goto free_card;
> +		if (err) {
> +			pr_warning("%s: Enabling packed event failed\n",
> +					mmc_hostname(card->host));
> +			card->ext_csd.packed_event_en = 0;
> +			err = 0;
> +		} else {
> +			card->ext_csd.packed_event_en = 1;
> +		}
> +	}
> +
>  	if (!oldcard)
>  		host->card = card;
>
> diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
> index d76513b..4aeb4e9 100644
> --- a/include/linux/mmc/card.h
> +++ b/include/linux/mmc/card.h
> @@ -53,6 +53,9 @@ struct mmc_ext_csd {
>  	u8			part_config;
>  	u8			cache_ctrl;
>  	u8			rst_n_function;
> +	u8			max_packed_writes;
> +	u8			max_packed_reads;
> +	u8			packed_event_en;
>  	unsigned int		part_time;		/* Units: ms */
>  	unsigned int		sa_timeout;		/* Units: 100ns */
>  	unsigned int		generic_cmd6_time;	/* Units: 10ms */
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index 9deb725..bb19b98 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -245,6 +245,10 @@ struct mmc_host {
>  #define MMC_CAP2_BROKEN_VOLTAGE	(1 << 7)	/* Use the broken voltage */
>  #define MMC_CAP2_DETECT_ON_ERR	(1 << 8)	/* On I/O err check card removal
> */
>  #define MMC_CAP2_HC_ERASE_SZ	(1 << 9)	/* High-capacity erase size */
> +#define MMC_CAP2_PACKED_RD	(1 << 10)	/* Allow packed read */
> +#define MMC_CAP2_PACKED_WR	(1 << 11)	/* Allow packed write */
> +#define MMC_CAP2_PACKED_CMD	(MMC_CAP2_PACKED_RD | \
> +				 MMC_CAP2_PACKED_WR) /* Allow packed commands */
>
>  	mmc_pm_flag_t		pm_caps;	/* supported pm features */
>  	unsigned int        power_notify_type;
> diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
> index d425cab..254901a 100644
> --- a/include/linux/mmc/mmc.h
> +++ b/include/linux/mmc/mmc.h
> @@ -139,6 +139,7 @@ static inline bool mmc_op_multi(u32 opcode)
>  #define R1_CURRENT_STATE(x)	((x & 0x00001E00) >> 9)	/* sx, b (4 bits) */
>  #define R1_READY_FOR_DATA	(1 << 8)	/* sx, a */
>  #define R1_SWITCH_ERROR		(1 << 7)	/* sx, c */
> +#define R1_EXP_EVENT		(1 << 6)	/* sr, a */
>  #define R1_APP_CMD		(1 << 5)	/* sr, c */
>
>  #define R1_STATE_IDLE	0
> @@ -274,6 +275,10 @@ struct _mmc_csd {
>  #define EXT_CSD_FLUSH_CACHE		32      /* W */
>  #define EXT_CSD_CACHE_CTRL		33      /* R/W */
>  #define EXT_CSD_POWER_OFF_NOTIFICATION	34	/* R/W */
> +#define EXT_CSD_PACKED_FAILURE_INDEX	35	/* RO */
> +#define EXT_CSD_PACKED_CMD_STATUS	36	/* RO */
> +#define EXT_CSD_EXP_EVENTS_STATUS	54	/* RO, 2 bytes */
> +#define EXT_CSD_EXP_EVENTS_CTRL	56	/* R/W, 2 bytes */
>  #define EXT_CSD_DATA_SECTOR_SIZE	61	/* R */
>  #define EXT_CSD_GP_SIZE_MULT		143	/* R/W */
>  #define EXT_CSD_PARTITION_ATTRIBUTE	156	/* R/W */
> @@ -318,6 +323,8 @@ struct _mmc_csd {
>  #define EXT_CSD_CACHE_SIZE		249	/* RO, 4 bytes */
>  #define EXT_CSD_TAG_UNIT_SIZE		498	/* RO */
>  #define EXT_CSD_DATA_TAG_SUPPORT	499	/* RO */
> +#define EXT_CSD_MAX_PACKED_WRITES	500	/* RO */
> +#define EXT_CSD_MAX_PACKED_READS	501	/* RO */
>  #define EXT_CSD_HPI_FEATURES		503	/* RO */
>
>  /*
> @@ -377,6 +384,14 @@ struct _mmc_csd {
>  #define EXT_CSD_PWR_CL_4BIT_MASK	0x0F	/* 8 bit PWR CLS */
>  #define EXT_CSD_PWR_CL_8BIT_SHIFT	4
>  #define EXT_CSD_PWR_CL_4BIT_SHIFT	0
> +
> +#define EXT_CSD_PACKED_EVENT_EN	(1 << 3)
> +
> +#define EXT_CSD_PACKED_FAILURE	(1 << 3)
> +
> +#define EXT_CSD_PACKED_GENERIC_ERROR	(1 << 0)
> +#define EXT_CSD_PACKED_INDEXED_ERROR	(1 << 1)
> +
>  /*
>   * MMC_SWITCH access modes
>   */
> --
> 1.7.0.4
>
>
>


-- 
Sent by consultant of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum

Re: [PATCH v8 1/2] mmc: add packed command feature of eMMC4.5

[Chris Ball]

Hi,

On Fri, Jun 29 2012, Seungwon Jeon wrote:
> This patch adds packed command feature of eMMC4.5.
> The maximum number for packing read(or write) is offered
> and exception event relevant to packed command which is
> used for error handling is enabled. If host wants to use
> this feature, MMC_CAP2_PACKED_CMD should be set.
>
> Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
> Reviewed-by: Maya Erez <merez@codeaurora.org>
> Reviewed-by: Subhash Jadavani <subhashj@codeaurora.org>
> Reviewed-by: Namjae Jeon <linkinjeon@gmail.com>
> ---
>  drivers/mmc/core/mmc.c   |   25 +++++++++++++++++++++++++
>  include/linux/mmc/card.h |    3 +++
>  include/linux/mmc/host.h |    4 ++++
>  include/linux/mmc/mmc.h  |   15 +++++++++++++++
>  4 files changed, 47 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 258b203..bfb271f 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -516,6 +516,11 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
>  		} else {
>  			card->ext_csd.data_tag_unit_size = 0;
>  		}
> +
> +		card->ext_csd.max_packed_writes =
> +			ext_csd[EXT_CSD_MAX_PACKED_WRITES];
> +		card->ext_csd.max_packed_reads =
> +			ext_csd[EXT_CSD_MAX_PACKED_READS];
>  	} else {
>  		card->ext_csd.data_sector_size = 512;
>  	}
> @@ -1246,6 +1251,26 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
>  		}
>  	}
>  
> +	if ((host->caps2 & MMC_CAP2_PACKED_WR &&
> +			card->ext_csd.max_packed_writes > 0) ||
> +	    (host->caps2 & MMC_CAP2_PACKED_RD &&
> +			card->ext_csd.max_packed_reads > 0)) {
> +		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> +				EXT_CSD_EXP_EVENTS_CTRL,
> +				EXT_CSD_PACKED_EVENT_EN,
> +				card->ext_csd.generic_cmd6_time);

Sorry, I don't have a copy of the eMMC 4.5 spec -- is PACKED_EVENT_EN
a one-time programmable fuse on the eMMC, like BKOPS_ENABLE was?

Thanks,

- Chris.
-- 
Chris Ball   <cjb@laptop.org>   <http://printf.net/>
One Laptop Per Child

Re: [PATCH v8 1/2] mmc: add packed command feature of eMMC4.5

[merez]

On Mon, July 9, 2012 10:54 pm, Chris Ball wrote:
> Hi,
>
> On Fri, Jun 29 2012, Seungwon Jeon wrote:
>> This patch adds packed command feature of eMMC4.5.
>> The maximum number for packing read(or write) is offered
>> and exception event relevant to packed command which is
>> used for error handling is enabled. If host wants to use
>> this feature, MMC_CAP2_PACKED_CMD should be set.
>>
>> Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
>> Reviewed-by: Maya Erez <merez@codeaurora.org>
>> Reviewed-by: Subhash Jadavani <subhashj@codeaurora.org>
>> Reviewed-by: Namjae Jeon <linkinjeon@gmail.com>
>> ---
>>  drivers/mmc/core/mmc.c   |   25 +++++++++++++++++++++++++
>>  include/linux/mmc/card.h |    3 +++
>>  include/linux/mmc/host.h |    4 ++++
>>  include/linux/mmc/mmc.h  |   15 +++++++++++++++
>>  4 files changed, 47 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
>> index 258b203..bfb271f 100644
>> --- a/drivers/mmc/core/mmc.c
>> +++ b/drivers/mmc/core/mmc.c
>> @@ -516,6 +516,11 @@ static int mmc_read_ext_csd(struct mmc_card *card,
>> u8 *ext_csd)
>>  		} else {
>>  			card->ext_csd.data_tag_unit_size = 0;
>>  		}
>> +
>> +		card->ext_csd.max_packed_writes =
>> +			ext_csd[EXT_CSD_MAX_PACKED_WRITES];
>> +		card->ext_csd.max_packed_reads =
>> +			ext_csd[EXT_CSD_MAX_PACKED_READS];
>>  	} else {
>>  		card->ext_csd.data_sector_size = 512;
>>  	}
>> @@ -1246,6 +1251,26 @@ static int mmc_init_card(struct mmc_host *host,
>> u32 ocr,
>>  		}
>>  	}
>>
>> +	if ((host->caps2 & MMC_CAP2_PACKED_WR &&
>> +			card->ext_csd.max_packed_writes > 0) ||
>> +	    (host->caps2 & MMC_CAP2_PACKED_RD &&
>> +			card->ext_csd.max_packed_reads > 0)) {
>> +		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
>> +				EXT_CSD_EXP_EVENTS_CTRL,
>> +				EXT_CSD_PACKED_EVENT_EN,
>> +				card->ext_csd.generic_cmd6_time);
>
> Sorry, I don't have a copy of the eMMC 4.5 spec -- is PACKED_EVENT_EN
> a one-time programmable fuse on the eMMC, like BKOPS_ENABLE was?
>
> Thanks,
>
> - Chris.
> --
> Chris Ball   <cjb@laptop.org>   <http://printf.net/>
> One Laptop Per Child

No, it's not.

-- 
Sent by consultant of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum

Re: [PATCH v8 1/2] mmc: add packed command feature of eMMC4.5

[S, Venkatraman]

On Tue, Jul 10, 2012 at 11:24 AM, Chris Ball <cjb@laptop.org> wrote:
> Hi,
>
> On Fri, Jun 29 2012, Seungwon Jeon wrote:
>> This patch adds packed command feature of eMMC4.5.
>> The maximum number for packing read(or write) is offered
>> and exception event relevant to packed command which is
>> used for error handling is enabled. If host wants to use
>> this feature, MMC_CAP2_PACKED_CMD should be set.
>>
>> Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
>> Reviewed-by: Maya Erez <merez@codeaurora.org>
>> Reviewed-by: Subhash Jadavani <subhashj@codeaurora.org>
>> Reviewed-by: Namjae Jeon <linkinjeon@gmail.com>
>> ---
>>  drivers/mmc/core/mmc.c   |   25 +++++++++++++++++++++++++
>>  include/linux/mmc/card.h |    3 +++
>>  include/linux/mmc/host.h |    4 ++++
>>  include/linux/mmc/mmc.h  |   15 +++++++++++++++
>>  4 files changed, 47 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
>> index 258b203..bfb271f 100644
>> --- a/drivers/mmc/core/mmc.c
>> +++ b/drivers/mmc/core/mmc.c
>> @@ -516,6 +516,11 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
>>               } else {
>>                       card->ext_csd.data_tag_unit_size = 0;
>>               }
>> +
>> +             card->ext_csd.max_packed_writes =
>> +                     ext_csd[EXT_CSD_MAX_PACKED_WRITES];
>> +             card->ext_csd.max_packed_reads =
>> +                     ext_csd[EXT_CSD_MAX_PACKED_READS];
>>       } else {
>>               card->ext_csd.data_sector_size = 512;
>>       }
>> @@ -1246,6 +1251,26 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
>>               }
>>       }
>>
>> +     if ((host->caps2 & MMC_CAP2_PACKED_WR &&
>> +                     card->ext_csd.max_packed_writes > 0) ||
>> +         (host->caps2 & MMC_CAP2_PACKED_RD &&
>> +                     card->ext_csd.max_packed_reads > 0)) {
>> +             err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
>> +                             EXT_CSD_EXP_EVENTS_CTRL,
>> +                             EXT_CSD_PACKED_EVENT_EN,
>> +                             card->ext_csd.generic_cmd6_time);
>
> Sorry, I don't have a copy of the eMMC 4.5 spec -- is PACKED_EVENT_EN
> a one-time programmable fuse on the eMMC, like BKOPS_ENABLE was?
>
It's not. PACKED_EVENT_EN is a bit set into EXCEPTION_EVENTS_CTRL
register, which is reset duing a power cycle

Re: [PATCH v8 1/2] mmc: add packed command feature of eMMC4.5

[Chris Ball]

Hi,

On Tue, Jul 10 2012, merez@codeaurora.org wrote:
>> Sorry, I don't have a copy of the eMMC 4.5 spec -- is PACKED_EVENT_EN
>> a one-time programmable fuse on the eMMC, like BKOPS_ENABLE was?
>
> No, it's not.

Excellent, thanks.

I've pushed both v8 patches to mmc-next.  Before pushing it up to Linus,
I'd like to get a better idea of the variety of performances differences
seen using packed writes -- has it been tried on devices from multiple
eMMC vendors, and multiple host controller vendors?  Can we try to build
up a quick table of results, with a standard test like iozone, to check
that we've got decent test coverage?  Seungwon suggests using:

iozone -az -i0 -I -s 10m -f /target/test -e

I'm also worried about how much code this is adding, but I agree that
it's worth it if the performance benefits are as described.

Thanks,

- Chris.
-- 
Chris Ball   <cjb@laptop.org>   <http://printf.net/>
One Laptop Per Child

Re: [PATCH v8 1/2] mmc: add packed command feature of eMMC4.5

[merez]

On Tue, July 10, 2012 12:33 am, Chris Ball wrote:
> Hi,
>
> On Tue, Jul 10 2012, merez@codeaurora.org wrote:
>>> Sorry, I don't have a copy of the eMMC 4.5 spec -- is PACKED_EVENT_EN
>>> a one-time programmable fuse on the eMMC, like BKOPS_ENABLE was?
>>
>> No, it's not.
>
> Excellent, thanks.
>
> I've pushed both v8 patches to mmc-next.  Before pushing it up to Linus,
> I'd like to get a better idea of the variety of performances differences
> seen using packed writes -- has it been tried on devices from multiple
> eMMC vendors, and multiple host controller vendors?  Can we try to build
> up a quick table of results, with a standard test like iozone, to check
> that we've got decent test coverage?  Seungwon suggests using:
>
> iozone -az -i0 -I -s 10m -f /target/test -e
>
> I'm also worried about how much code this is adding, but I agree that
> it's worth it if the performance benefits are as described.
>
> Thanks,
>
> - Chris.
> --
> Chris Ball   <cjb@laptop.org>   <http://printf.net/>
> One Laptop Per Child
> --

Hi Chris,

I suggest to also use lmdd as a benchmark test for write packing, since
write packing is mostly beneficial in long sequential operations.
It can be used as follows:
lmdd if=internal of=/data/file1 bs=128k count=3000

Thanks,
Maya
-- 
Sent by consultant of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum