diff options
Diffstat (limited to 'drivers/mtd/nand/raw/mxs_nand.c')
| -rw-r--r-- | drivers/mtd/nand/raw/mxs_nand.c | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/drivers/mtd/nand/raw/mxs_nand.c b/drivers/mtd/nand/raw/mxs_nand.c index 7893e9d7e3..65eab4c808 100644 --- a/drivers/mtd/nand/raw/mxs_nand.c +++ b/drivers/mtd/nand/raw/mxs_nand.c @@ -14,6 +14,7 @@ */ #include <common.h> +#include <clk.h> #include <cpu_func.h> #include <dm.h> #include <dm/device_compat.h> @@ -26,10 +27,12 @@ #include <asm/io.h> #include <asm/mach-imx/regs-bch.h> #include <asm/mach-imx/regs-gpmi.h> +#include <linux/delay.h> #include <linux/errno.h> #include <linux/mtd/rawnand.h> #include <linux/sizes.h> #include <linux/types.h> +#include <linux/math64.h> #define MXS_NAND_DMA_DESCRIPTOR_COUNT 4 @@ -49,6 +52,10 @@ #endif #define MXS_NAND_BCH_TIMEOUT 10000 +#define USEC_PER_SEC 1000000 +#define NSEC_PER_SEC 1000000000L + +#define TO_CYCLES(duration, period) DIV_ROUND_UP_ULL(duration, period) struct nand_ecclayout fake_ecc_layout; @@ -1344,6 +1351,196 @@ err1: return ret; } +/* + * <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. + * C : a constant to adjust the delay. default is 4000ps. + * tRP : the read pulse width, which is exactly: + * 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 16000ps, but in mx6q, we use 12000ps. + * + * 4.3) since {1} equals {2}, we get: + * + * (tREA + 4000 - tRP) * 8 + * RDN_DELAY = ----------------------- {3} + * RP + */ +static void mxs_compute_timings(struct nand_chip *chip, + const struct nand_sdr_timings *sdr) +{ + struct mxs_nand_info *nand_info = nand_get_controller_data(chip); + unsigned long clk_rate; + unsigned int dll_wait_time_us; + unsigned int dll_threshold_ps = nand_info->max_chain_delay; + unsigned int period_ps, reference_period_ps; + unsigned int data_setup_cycles, data_hold_cycles, addr_setup_cycles; + unsigned int tRP_ps; + bool use_half_period; + int sample_delay_ps, sample_delay_factor; + u16 busy_timeout_cycles; + u8 wrn_dly_sel; + u32 timing0; + u32 timing1; + u32 ctrl1n; + + if (sdr->tRC_min >= 30000) { + /* ONFI non-EDO modes [0-3] */ + clk_rate = 22000000; + wrn_dly_sel = GPMI_CTRL1_WRN_DLY_SEL_4_TO_8NS; + } else if (sdr->tRC_min >= 25000) { + /* ONFI EDO mode 4 */ + clk_rate = 80000000; + wrn_dly_sel = GPMI_CTRL1_WRN_DLY_SEL_NO_DELAY; + debug("%s, setting ONFI onfi edo 4\n", __func__); + } else { + /* ONFI EDO mode 5 */ + clk_rate = 100000000; + wrn_dly_sel = GPMI_CTRL1_WRN_DLY_SEL_NO_DELAY; + debug("%s, setting ONFI onfi edo 5\n", __func__); + } + + /* SDR core timings are given in picoseconds */ + period_ps = div_u64((u64)NSEC_PER_SEC * 1000, clk_rate); + + addr_setup_cycles = TO_CYCLES(sdr->tALS_min, period_ps); + data_setup_cycles = TO_CYCLES(sdr->tDS_min, period_ps); + data_hold_cycles = TO_CYCLES(sdr->tDH_min, period_ps); + busy_timeout_cycles = TO_CYCLES(sdr->tWB_max + sdr->tR_max, period_ps); + + timing0 = (addr_setup_cycles << GPMI_TIMING0_ADDRESS_SETUP_OFFSET) | + (data_hold_cycles << GPMI_TIMING0_DATA_HOLD_OFFSET) | + (data_setup_cycles << GPMI_TIMING0_DATA_SETUP_OFFSET); + timing1 = (busy_timeout_cycles * 4096) << GPMI_TIMING1_DEVICE_BUSY_TIMEOUT_OFFSET; + + /* + * Derive NFC ideal delay from {3}: + * + * (tREA + 4000 - tRP) * 8 + * RDN_DELAY = ----------------------- + * RP + */ + if (period_ps > dll_threshold_ps) { + use_half_period = true; + reference_period_ps = period_ps / 2; + } else { + use_half_period = false; + reference_period_ps = period_ps; + } + + tRP_ps = data_setup_cycles * period_ps; + sample_delay_ps = (sdr->tREA_max + 4000 - tRP_ps) * 8; + if (sample_delay_ps > 0) + sample_delay_factor = sample_delay_ps / reference_period_ps; + else + sample_delay_factor = 0; + + ctrl1n = (wrn_dly_sel << GPMI_CTRL1_WRN_DLY_SEL_OFFSET); + if (sample_delay_factor) + ctrl1n |= (sample_delay_factor << GPMI_CTRL1_RDN_DELAY_OFFSET) | + GPMI_CTRL1_DLL_ENABLE | + (use_half_period ? GPMI_CTRL1_HALF_PERIOD : 0); + + writel(timing0, &nand_info->gpmi_regs->hw_gpmi_timing0); + writel(timing1, &nand_info->gpmi_regs->hw_gpmi_timing1); + + /* + * Clear several CTRL1 fields, DLL must be disabled when setting + * RDN_DELAY or HALF_PERIOD. + */ + writel(GPMI_CTRL1_CLEAR_MASK, &nand_info->gpmi_regs->hw_gpmi_ctrl1_clr); + writel(ctrl1n, &nand_info->gpmi_regs->hw_gpmi_ctrl1_set); + + clk_set_rate(nand_info->gpmi_clk, clk_rate); + + /* Wait 64 clock cycles before using the GPMI after enabling the DLL */ + dll_wait_time_us = USEC_PER_SEC / clk_rate * 64; + if (!dll_wait_time_us) + dll_wait_time_us = 1; + + /* Wait for the DLL to settle. */ + udelay(dll_wait_time_us); +} + +static int mxs_nand_setup_interface(struct mtd_info *mtd, int chipnr, + const struct nand_data_interface *conf) +{ + struct nand_chip *chip = mtd_to_nand(mtd); + const struct nand_sdr_timings *sdr; + + sdr = nand_get_sdr_timings(conf); + if (IS_ERR(sdr)) + return PTR_ERR(sdr); + + /* Stop here if this call was just a check */ + if (chipnr < 0) + return 0; + + /* Do the actual derivation of the controller timings */ + mxs_compute_timings(chip, sdr); + + return 0; +} + int mxs_nand_init_spl(struct nand_chip *nand) { struct mxs_nand_info *nand_info; @@ -1432,6 +1629,9 @@ int mxs_nand_init_ctrl(struct mxs_nand_info *nand_info) nand->read_buf = mxs_nand_read_buf; nand->write_buf = mxs_nand_write_buf; + if (nand_info->gpmi_clk) + nand->setup_data_interface = mxs_nand_setup_interface; + /* first scan to find the device and get the page size */ if (nand_scan_ident(mtd, CONFIG_SYS_MAX_NAND_DEVICE, NULL)) goto err_free_buffers; |