Hi, On Thu, Nov 29, 2012 at 7:20 AM, Jae hoon Chung <jh80.ch...@gmail.com> wrote: > Hi Simon, > > Is it saved the 200ms? Could you tell me your environment? > I will check this patch..and share the result.
The environment is snow (Samsung ARM Chromebook). The time save only comes from not waiting for the MMC init. So: 1. Kick off MMC init 2. Go off and do something else for 200ms 3. Come back and MMC init should complete immediately Regards, Simon > > Best Regards, > Jaehoon Chung > > 2012/11/29 Simon Glass <s...@chromium.org>: >> From: Che-Liang Chiou <clch...@chromium.org> >> >> Most of time that MMC driver spends on initializing a device is polling >> OCR (operation conditions register). To decouple this polling loop, >> device init is split into two parts: The first part fires the OCR query >> command, and the second part polls the result. So the caller is now no >> longer bound to the OCR-polling delay; he may fire the query, go >> somewhere and then come back later for the result. >> >> To use this, call mmc_set_preinit() on any device which needs this. >> >> This can save significant amounts of time on boot (e.g. 200ms) by >> hiding the MMC init time behind other init. >> >> Signed-off-by: Che-Liang Chiou <clch...@chromium.org> >> Signed-off-by: Simon Glass <s...@chromium.org> >> --- >> Changes in v2: >> - Rebase to master >> >> drivers/mmc/mmc.c | 137 >> ++++++++++++++++++++++++++++++++++++++++------------ >> include/mmc.h | 30 ++++++++++++ >> 2 files changed, 135 insertions(+), 32 deletions(-) >> >> diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c >> index 72e8ce6..09695e8 100644 >> --- a/drivers/mmc/mmc.c >> +++ b/drivers/mmc/mmc.c >> @@ -503,48 +503,70 @@ static int sd_send_op_cond(struct mmc *mmc) >> return 0; >> } >> >> -static int mmc_send_op_cond(struct mmc *mmc) >> +/* We pass in the cmd since otherwise the init seems to fail */ >> +static int mmc_send_op_cond_iter(struct mmc *mmc, struct mmc_cmd *cmd, >> + int use_arg) >> { >> - int timeout = 10000; >> - struct mmc_cmd cmd; >> int err; >> >> + cmd->cmdidx = MMC_CMD_SEND_OP_COND; >> + cmd->resp_type = MMC_RSP_R3; >> + cmd->cmdarg = 0; >> + if (use_arg && !mmc_host_is_spi(mmc)) { >> + cmd->cmdarg = >> + (mmc->voltages & >> + (mmc->op_cond_response & OCR_VOLTAGE_MASK)) | >> + (mmc->op_cond_response & OCR_ACCESS_MODE); >> + >> + if (mmc->host_caps & MMC_MODE_HC) >> + cmd->cmdarg |= OCR_HCS; >> + } >> + err = mmc_send_cmd(mmc, cmd, NULL); >> + if (err) >> + return err; >> + mmc->op_cond_response = cmd->response[0]; >> + return 0; >> +} >> + >> +int mmc_send_op_cond(struct mmc *mmc) >> +{ >> + struct mmc_cmd cmd; >> + int err, i; >> + >> /* Some cards seem to need this */ >> mmc_go_idle(mmc); >> >> /* Asking to the card its capabilities */ >> - cmd.cmdidx = MMC_CMD_SEND_OP_COND; >> - cmd.resp_type = MMC_RSP_R3; >> - cmd.cmdarg = 0; >> - >> - err = mmc_send_cmd(mmc, &cmd, NULL); >> + mmc->op_cond_pending = 1; >> + for (i = 0; i < 2; i++) { >> + err = mmc_send_op_cond_iter(mmc, &cmd, i != 0); >> + if (err) >> + return err; >> >> - if (err) >> - return err; >> + /* exit if not busy (flag seems to be inverted) */ >> + if (mmc->op_cond_response & OCR_BUSY) >> + return 0; >> + } >> + return IN_PROGRESS; >> +} >> >> - udelay(1000); >> +int mmc_complete_op_cond(struct mmc *mmc) >> +{ >> + struct mmc_cmd cmd; >> + int timeout = 1000; >> + uint start; >> + int err; >> >> + mmc->op_cond_pending = 0; >> + start = get_timer(0); >> do { >> - cmd.cmdidx = MMC_CMD_SEND_OP_COND; >> - cmd.resp_type = MMC_RSP_R3; >> - cmd.cmdarg = (mmc_host_is_spi(mmc) ? 0 : >> - (mmc->voltages & >> - (cmd.response[0] & OCR_VOLTAGE_MASK)) | >> - (cmd.response[0] & OCR_ACCESS_MODE)); >> - >> - if (mmc->host_caps & MMC_MODE_HC) >> - cmd.cmdarg |= OCR_HCS; >> - >> - err = mmc_send_cmd(mmc, &cmd, NULL); >> - >> + err = mmc_send_op_cond_iter(mmc, &cmd, 1); >> if (err) >> return err; >> - >> - udelay(1000); >> - } while (!(cmd.response[0] & OCR_BUSY) && timeout--); >> - >> - if (timeout <= 0) >> - return UNUSABLE_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; >> @@ -1227,7 +1249,7 @@ block_dev_desc_t *mmc_get_dev(int dev) >> } >> #endif >> >> -int mmc_init(struct mmc *mmc) >> +int mmc_start_init(struct mmc *mmc) >> { >> int err; >> >> @@ -1267,17 +1289,48 @@ int mmc_init(struct mmc *mmc) >> if (err == TIMEOUT) { >> err = mmc_send_op_cond(mmc); >> >> - if (err) { >> + if (err && err != IN_PROGRESS) { >> printf("Card did not respond to voltage select!\n"); >> return UNUSABLE_ERR; >> } >> } >> >> - err = mmc_startup(mmc); >> + if (err == IN_PROGRESS) >> + mmc->init_in_progress = 1; >> + >> + return err; >> +} >> + >> +static int mmc_complete_init(struct mmc *mmc) >> +{ >> + int err = 0; >> + >> + if (mmc->op_cond_pending) >> + err = mmc_complete_op_cond(mmc); >> + >> + if (!err) >> + err = mmc_startup(mmc); >> if (err) >> mmc->has_init = 0; >> else >> mmc->has_init = 1; >> + mmc->init_in_progress = 0; >> + return err; >> +} >> + >> +int mmc_init(struct mmc *mmc) >> +{ >> + int err = IN_PROGRESS; >> + unsigned start = get_timer(0); >> + >> + if (mmc->has_init) >> + return 0; >> + if (!mmc->init_in_progress) >> + err = mmc_start_init(mmc); >> + >> + if (!err || err == IN_PROGRESS) >> + err = mmc_complete_init(mmc); >> + debug("%s: %d, time %lu\n", __func__, err, get_timer(start)); >> return err; >> } >> >> @@ -1315,6 +1368,25 @@ int get_mmc_num(void) >> return cur_dev_num; >> } >> >> +void mmc_set_preinit(struct mmc *mmc, int preinit) >> +{ >> + mmc->preinit = preinit; >> +} >> + >> +static void do_preinit(void) >> +{ >> + struct mmc *m; >> + struct list_head *entry; >> + >> + list_for_each(entry, &mmc_devices) { >> + m = list_entry(entry, struct mmc, link); >> + >> + if (m->preinit) >> + mmc_start_init(m); >> + } >> +} >> + >> + >> int mmc_initialize(bd_t *bis) >> { >> INIT_LIST_HEAD (&mmc_devices); >> @@ -1325,5 +1397,6 @@ int mmc_initialize(bd_t *bis) >> >> print_mmc_devices(','); >> >> + do_preinit(); >> return 0; >> } >> diff --git a/include/mmc.h b/include/mmc.h >> index a13e2bd..445d714 100644 >> --- a/include/mmc.h >> +++ b/include/mmc.h >> @@ -62,6 +62,7 @@ >> #define UNUSABLE_ERR -17 /* Unusable Card */ >> #define COMM_ERR -18 /* Communications Error */ >> #define TIMEOUT -19 >> +#define IN_PROGRESS -20 /* operation is in progress */ >> >> #define MMC_CMD_GO_IDLE_STATE 0 >> #define MMC_CMD_SEND_OP_COND 1 >> @@ -260,6 +261,10 @@ struct mmc { >> int (*init)(struct mmc *mmc); >> int (*getcd)(struct mmc *mmc); >> uint b_max; >> + char op_cond_pending; /* 1 if we are waiting on an op_cond command >> */ >> + char init_in_progress; /* 1 if we have done mmc_start_init() */ >> + char preinit; /* start init as early as possible */ >> + uint op_cond_response; /* the response byte from the last op_cond */ >> }; >> >> int mmc_register(struct mmc *mmc); >> @@ -276,6 +281,31 @@ int mmc_switch_part(int dev_num, unsigned int part_num); >> int mmc_getcd(struct mmc *mmc); >> void spl_mmc_load(void) __noreturn; >> >> +/** >> + * Start device initialization and return immediately; it does not block on >> + * polling OCR (operation condition register) status. Then you should call >> + * mmc_init, which would block on polling OCR status and complete the device >> + * initializatin. >> + * >> + * @param mmc Pointer to a MMC device struct >> + * @return 0 on success, IN_PROGRESS on waiting for OCR status, <0 on error. >> + */ >> +int mmc_start_init(struct mmc *mmc); >> + >> +/** >> + * Set preinit flag of mmc device. >> + * >> + * This will cause the device to be pre-inited during mmc_initialize(), >> + * which may save boot time if the device is not accessed until later. >> + * Some eMMC devices take 200-300ms to init, but unfortunately they >> + * must be sent a series of commands to even get them to start preparing >> + * for operation. >> + * >> + * @param mmc Pointer to a MMC device struct >> + * @param preinit preinit flag value >> + */ >> +void mmc_set_preinit(struct mmc *mmc, int preinit); >> + >> #ifdef CONFIG_GENERIC_MMC >> #define mmc_host_is_spi(mmc) ((mmc)->host_caps & MMC_MODE_SPI) >> struct mmc *mmc_spi_init(uint bus, uint cs, uint speed, uint mode); >> -- >> 1.7.7.3 >> >> _______________________________________________ >> U-Boot mailing list >> U-Boot@lists.denx.de >> http://lists.denx.de/mailman/listinfo/u-boot _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot