From 995fbbf563fcec058a1135bdd112ac969c817e65 Mon Sep 17 00:00:00 2001 From: Huang Shijie Date: Thu, 13 Sep 2012 14:57:59 +0800 Subject: [PATCH] mtd: gpmi: add EDO feature for imx6q When the frequency on the nand chip pins is above 33MHz, the nand EDO(extended Data Out) timing could be applied. The GPMI implements a Feedback read strobe to sample the read data in the EDO timing mode. This patch adds the EDO feature for the gpmi-nand driver. For some onfi nand chips, the mode 4 is the fastest; while for other onfi nand chips, the mode 5 is the fastest. This patch only adds the support for the fastest asynchronous timing mode. So this patch only supports the mode 4 and mode 5. I tested several Micron's ONFI nand chips with EDO enabled, take Micron MT29F32G08MAA for example (in mode 5, 100MHz): 1) The test result BEFORE we add the EDO feature: ================================================= mtd_speedtest: MTD device: 2 mtd_speedtest: MTD device size 209715200, eraseblock size 524288, page size 4096, count of eraseblocks 400, pages per eraseblock 128, OOB size 218 ....................................... mtd_speedtest: testing eraseblock read speed mtd_speedtest: eraseblock read speed is 3632 KiB/s ....................................... mtd_speedtest: testing page read speed mtd_speedtest: page read speed is 3554 KiB/s ....................................... mtd_speedtest: testing 2 page read speed mtd_speedtest: 2 page read speed is 3592 KiB/s ....................................... ================================================= 2) The test result AFTER we add the EDO feature: ================================================= mtd_speedtest: MTD device: 2 mtd_speedtest: MTD device size 209715200, eraseblock size 524288, page size 4096, count of eraseblocks 400, pages per eraseblock 128, OOB size 218 ....................................... mtd_speedtest: testing eraseblock read speed mtd_speedtest: eraseblock read speed is 19555 KiB/s ....................................... mtd_speedtest: testing page read speed mtd_speedtest: page read speed is 17319 KiB/s ....................................... mtd_speedtest: testing 2 page read speed mtd_speedtest: 2 page read speed is 18339 KiB/s ....................................... ================================================= 3) The read data performance is much improved by more then 5 times. Signed-off-by: Huang Shijie Signed-off-by: Artem Bityutskiy Signed-off-by: David Woodhouse --- drivers/mtd/nand/gpmi-nand/gpmi-lib.c | 214 ++++++++++++++++++++++++- drivers/mtd/nand/gpmi-nand/gpmi-nand.c | 8 + drivers/mtd/nand/gpmi-nand/gpmi-nand.h | 6 + 3 files changed, 227 insertions(+), 1 deletion(-) diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c index 010665ca631a..c036e51f3200 100644 --- a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c +++ b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c @@ -737,6 +737,215 @@ return_results: return 0; } +/* + * <1> Firstly, we should know what's the GPMI-clock means. + * The GPMI-clock is the internal clock in the gpmi nand controller. + * If you set 100MHz to gpmi nand controller, the GPMI-clock's period + * is 10ns. Mark the GPMI-clock's period as GPMI-clock-period. + * + * <2> Secondly, we should know what's the frequency on the nand chip pins. + * The frequency on the nand chip pins is derived from the GPMI-clock. + * We can get it from the following equation: + * + * F = G / (DS + DH) + * + * F : the frequency on the nand chip pins. + * G : the GPMI clock, such as 100MHz. + * DS : GPMI_HW_GPMI_TIMING0:DATA_SETUP + * DH : GPMI_HW_GPMI_TIMING0:DATA_HOLD + * + * <3> Thirdly, when the frequency on the nand chip pins is above 33MHz, + * the nand EDO(extended Data Out) timing could be applied. + * The GPMI implements a feedback read strobe to sample the read data. + * The feedback read strobe can be delayed to support the nand EDO timing + * where the read strobe may deasserts before the read data is valid, and + * read data is valid for some time after read strobe. + * + * The following figure illustrates some aspects of a NAND Flash read: + * + * |<---tREA---->| + * | | + * | | | + * |<--tRP-->| | + * | | | + * __ ___|__________________________________ + * RDN \________/ | + * | + * /---------\ + * Read Data --------------< >--------- + * \---------/ + * | | + * |<-D->| + * FeedbackRDN ________ ____________ + * \___________/ + * + * D stands for delay, set in the HW_GPMI_CTRL1:RDN_DELAY. + * + * + * <4> Now, we begin to describe how to compute the right RDN_DELAY. + * + * 4.1) From the aspect of the nand chip pins: + * Delay = (tREA + C - tRP) {1} + * + * tREA : the maximum read access time. From the ONFI nand standards, + * we know that tREA is 16ns in mode 5, tREA is 20ns is mode 4. + * Please check it in : www.onfi.org + * C : a constant for adjust the delay. default is 4. + * tRP : the read pulse width. + * Specified by the HW_GPMI_TIMING0:DATA_SETUP: + * tRP = (GPMI-clock-period) * DATA_SETUP + * + * 4.2) From the aspect of the GPMI nand controller: + * Delay = RDN_DELAY * 0.125 * RP {2} + * + * RP : the DLL reference period. + * if (GPMI-clock-period > DLL_THRETHOLD) + * RP = GPMI-clock-period / 2; + * else + * RP = GPMI-clock-period; + * + * Set the HW_GPMI_CTRL1:HALF_PERIOD if GPMI-clock-period + * is greater DLL_THRETHOLD. In other SOCs, the DLL_THRETHOLD + * is 16ns, but in mx6q, we use 12ns. + * + * 4.3) since {1} equals {2}, we get: + * + * (tREA + 4 - tRP) * 8 + * RDN_DELAY = --------------------- {3} + * RP + * + * 4.4) We only support the fastest asynchronous mode of ONFI nand. + * For some ONFI nand, the mode 4 is the fastest mode; + * while for some ONFI nand, the mode 5 is the fastest mode. + * So we only support the mode 4 and mode 5. It is no need to + * support other modes. + */ +static void gpmi_compute_edo_timing(struct gpmi_nand_data *this, + struct gpmi_nfc_hardware_timing *hw) +{ + struct resources *r = &this->resources; + unsigned long rate = clk_get_rate(r->clock[0]); + int mode = this->timing_mode; + int dll_threshold = 16; /* in ns */ + unsigned long delay; + unsigned long clk_period; + int t_rea; + int c = 4; + int t_rp; + int rp; + + /* + * [1] for GPMI_HW_GPMI_TIMING0: + * The async mode requires 40MHz for mode 4, 50MHz for mode 5. + * The GPMI can support 100MHz at most. So if we want to + * get the 40MHz or 50MHz, we have to set DS=1, DH=1. + * Set the ADDRESS_SETUP to 0 in mode 4. + */ + hw->data_setup_in_cycles = 1; + hw->data_hold_in_cycles = 1; + hw->address_setup_in_cycles = ((mode == 5) ? 1 : 0); + + /* [2] for GPMI_HW_GPMI_TIMING1 */ + hw->device_busy_timeout = 0x9000; + + /* [3] for GPMI_HW_GPMI_CTRL1 */ + hw->wrn_dly_sel = BV_GPMI_CTRL1_WRN_DLY_SEL_NO_DELAY; + + if (GPMI_IS_MX6Q(this)) + dll_threshold = 12; + + /* + * Enlarge 10 times for the numerator and denominator in {3}. + * This make us to get more accurate result. + */ + clk_period = NSEC_PER_SEC / (rate / 10); + dll_threshold *= 10; + t_rea = ((mode == 5) ? 16 : 20) * 10; + c *= 10; + + t_rp = clk_period * 1; /* DATA_SETUP is 1 */ + + if (clk_period > dll_threshold) { + hw->use_half_periods = 1; + rp = clk_period / 2; + } else { + hw->use_half_periods = 0; + rp = clk_period; + } + + /* + * Multiply the numerator with 10, we could do a round off: + * 7.8 round up to 8; 7.4 round down to 7. + */ + delay = (((t_rea + c - t_rp) * 8) * 10) / rp; + delay = (delay + 5) / 10; + + hw->sample_delay_factor = delay; +} + +static int enable_edo_mode(struct gpmi_nand_data *this, int mode) +{ + struct resources *r = &this->resources; + struct nand_chip *nand = &this->nand; + struct mtd_info *mtd = &this->mtd; + uint8_t feature[ONFI_SUBFEATURE_PARAM_LEN] = {}; + unsigned long rate; + int ret; + + nand->select_chip(mtd, 0); + + /* [1] send SET FEATURE commond to NAND */ + feature[0] = mode; + ret = nand->onfi_set_features(mtd, nand, + ONFI_FEATURE_ADDR_TIMING_MODE, feature); + if (ret) + goto err_out; + + /* [2] send GET FEATURE command to double-check the timing mode */ + memset(feature, 0, ONFI_SUBFEATURE_PARAM_LEN); + ret = nand->onfi_get_features(mtd, nand, + ONFI_FEATURE_ADDR_TIMING_MODE, feature); + if (ret || feature[0] != mode) + goto err_out; + + nand->select_chip(mtd, -1); + + /* [3] set the main IO clock, 100MHz for mode 5, 80MHz for mode 4. */ + rate = (mode == 5) ? 100000000 : 80000000; + clk_set_rate(r->clock[0], rate); + + this->flags |= GPMI_ASYNC_EDO_ENABLED; + this->timing_mode = mode; + dev_info(this->dev, "enable the asynchronous EDO mode %d\n", mode); + return 0; + +err_out: + nand->select_chip(mtd, -1); + dev_err(this->dev, "mode:%d ,failed in set feature.\n", mode); + return -EINVAL; +} + +int gpmi_extra_init(struct gpmi_nand_data *this) +{ + struct nand_chip *chip = &this->nand; + + /* Enable the asynchronous EDO feature. */ + if (GPMI_IS_MX6Q(this) && chip->onfi_version) { + int mode = onfi_get_async_timing_mode(chip); + + /* We only support the timing mode 4 and mode 5. */ + if (mode & ONFI_TIMING_MODE_5) + mode = 5; + else if (mode & ONFI_TIMING_MODE_4) + mode = 4; + else + return 0; + + return enable_edo_mode(this, mode); + } + return 0; +} + /* Begin the I/O */ void gpmi_begin(struct gpmi_nand_data *this) { @@ -755,7 +964,10 @@ void gpmi_begin(struct gpmi_nand_data *this) goto err_out; } - gpmi_nfc_compute_hardware_timing(this, &hw); + if (this->flags & GPMI_ASYNC_EDO_ENABLED) + gpmi_compute_edo_timing(this, &hw); + else + gpmi_nfc_compute_hardware_timing(this, &hw); /* [1] Set HW_GPMI_TIMING0 */ reg = BF_GPMI_TIMING0_ADDRESS_SETUP(hw.address_setup_in_cycles) | diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c index 2bfd44876f81..d79696b2f19b 100644 --- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c +++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c @@ -1517,6 +1517,14 @@ static int gpmi_scan_bbt(struct mtd_info *mtd) if (ret) return ret; + /* + * Can we enable the extra features? such as EDO or Sync mode. + * + * We do not check the return value now. That's means if we fail in + * enable the extra features, we still can run in the normal way. + */ + gpmi_extra_init(this); + /* use the default BBT implementation */ return nand_default_bbt(mtd); } diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-nand.h b/drivers/mtd/nand/gpmi-nand/gpmi-nand.h index 5c11e761a32e..5b6d546711a6 100644 --- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.h +++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.h @@ -122,6 +122,10 @@ struct nand_timing { }; struct gpmi_nand_data { + /* flags */ +#define GPMI_ASYNC_EDO_ENABLED (1 << 0) + int flags; + /* System Interface */ struct device *dev; struct platform_device *pdev; @@ -132,6 +136,7 @@ struct gpmi_nand_data { /* Flash Hardware */ struct nand_timing timing; + int timing_mode; /* BCH */ struct bch_geometry bch_geometry; @@ -259,6 +264,7 @@ extern int start_dma_with_bch_irq(struct gpmi_nand_data *, /* GPMI-NAND helper function library */ extern int gpmi_init(struct gpmi_nand_data *); +extern int gpmi_extra_init(struct gpmi_nand_data *); extern void gpmi_clear_bch(struct gpmi_nand_data *); extern void gpmi_dump_info(struct gpmi_nand_data *); extern int bch_set_geometry(struct gpmi_nand_data *); -- 2.20.1