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Message-ID: <4FBA273B.6010106@codeaurora.org>
Date: Mon, 21 May 2012 17:00:03 +0530
From: Subhash Jadavani <subhashj@...eaurora.org>
To: Seungwon Jeon <tgih.jun@...sung.com>
CC: linux-mmc@...r.kernel.org, 'Chris Ball' <cjb@...top.org>,
merez@...eaurora.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 1/3] mmc: core: Add packed command feature of eMMC4.5
Hi Seungwon,
Sorry for commenting on this late. I have one comment below. Please
check if it makes sense or not.
On 5/17/2012 3:10 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@...sung.com>
> ---
> drivers/mmc/core/mmc.c | 24 ++++++++++++++++++++++++
> include/linux/mmc/card.h | 3 +++
> include/linux/mmc/host.h | 4 ++++
> include/linux/mmc/mmc.h | 15 +++++++++++++++
> 4 files changed, 46 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 2f0e11c..8310ce8 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];
> }
>
> out:
> @@ -1244,6 +1249,25 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
> }
> }
>
> + if ((host->caps2& MMC_CAP2_PACKED_CMD)&&
> + (card->ext_csd.max_packed_writes> 0)&&
> + (card->ext_csd.max_packed_reads> 0)) {
why both max_packed_reads and max_packed_writes need to be non-zero to
enable the write packing event? What if write packing is not supported
by card and only read packing is supported? Shouldn't we still make the
read packing work?
I would suggest to change it like this:
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 0707d22..9d0d946 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -238,6 +238,10 @@ 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
> */
--
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