[PATCH v9 2/3] MTD : add helper functions library and header files for GPMI NAND driver
From: Huang Shijie <hidden>
Date: 2011-08-22 05:03:56
Hi,
On Wednesday, August 17, 2011 01:50:27 PM Huang Shijie wrote:quoted
bch-regs.h : registers file for BCH module gpmi-regs.h: registers file for GPMI module gpmi-lib.c: helper functions library. Signed-off-by: Huang Shijie<redacted> --- drivers/mtd/nand/gpmi-nand/bch-regs.h | 88 +++ drivers/mtd/nand/gpmi-nand/gpmi-lib.c | 978 ++++++++++++++++++++++++++++++++ drivers/mtd/nand/gpmi-nand/gpmi-regs.h | 174 ++++++ 3 files changed, 1240 insertions(+), 0 deletions(-) create mode 100644 drivers/mtd/nand/gpmi-nand/bch-regs.h create mode 100644 drivers/mtd/nand/gpmi-nand/gpmi-lib.c create mode 100644 drivers/mtd/nand/gpmi-nand/gpmi-regs.hdiff --git a/drivers/mtd/nand/gpmi-nand/bch-regs.hb/drivers/mtd/nand/gpmi-nand/bch-regs.h new file mode 100644 index 0000000..cec1dfa--- /dev/null +++ b/drivers/mtd/nand/gpmi-nand/bch-regs.h@@ -0,0 +1,88 @@ +/* + * Freescale GPMI NAND Flash Driver + * + * Copyright 2008-2011 Freescale Semiconductor, Inc. + * Copyright 2008 Embedded Alley Solutions, Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ +#ifndef __GPMI_NAND_BCH_REGS_H +#define __GPMI_NAND_BCH_REGS_H +Aaargh, please remove these separators.
ok.
quoted
+/*======================================================================== ====*/ +#define HW_BCH_CTRL 0x00000000 +#define HW_BCH_CTRL_SET 0x00000004 +#define HW_BCH_CTRL_CLR 0x00000008 +#define HW_BCH_CTRL_TOG 0x0000000c + +#define BM_BCH_CTRL_COMPLETE_IRQ_EN (1<< 8) +#define BM_BCH_CTRL_COMPLETE_IRQ (1<< 0) + +/*======================================================================== ====*/ +#define HW_BCH_STATUS0 0x00000010 +#define HW_BCH_MODE 0x00000020 +#define HW_BCH_ENCODEPTR 0x00000030 +#define HW_BCH_DATAPTR 0x00000040 +#define HW_BCH_METAPTR 0x00000050 +#define HW_BCH_LAYOUTSELECT 0x00000070 + +/*======================================================================== ====*/ +#define HW_BCH_FLASH0LAYOUT0 0x00000080 + +#define BP_BCH_FLASH0LAYOUT0_NBLOCKS 24 +#define BM_BCH_FLASH0LAYOUT0_NBLOCKS (0xff<< BP_BCH_FLASH0LAYOUT0_NBLOCKS) +#define BF_BCH_FLASH0LAYOUT0_NBLOCKS(v) \ + (((v)<< BP_BCH_FLASH0LAYOUT0_NBLOCKS)& BM_BCH_FLASH0LAYOUT0_NBLOCKS) + +#define BP_BCH_FLASH0LAYOUT0_META_SIZE 16 +#define BM_BCH_FLASH0LAYOUT0_META_SIZE (0xff<< BP_BCH_FLASH0LAYOUT0_META_SIZE) +#define BF_BCH_FLASH0LAYOUT0_META_SIZE(v) \ + (((v)<< BP_BCH_FLASH0LAYOUT0_META_SIZE)\ + & BM_BCH_FLASH0LAYOUT0_META_SIZE) + +#define BP_BCH_FLASH0LAYOUT0_ECC0 12 +#define BM_BCH_FLASH0LAYOUT0_ECC0 (0xf<< BP_BCH_FLASH0LAYOUT0_ECC0) +#define BF_BCH_FLASH0LAYOUT0_ECC0(v) \ + (((v)<< BP_BCH_FLASH0LAYOUT0_ECC0)& BM_BCH_FLASH0LAYOUT0_ECC0) + +#define BP_BCH_FLASH0LAYOUT0_DATA0_SIZE 0 +#define BM_BCH_FLASH0LAYOUT0_DATA0_SIZE \ + (0xfff<< BP_BCH_FLASH0LAYOUT0_DATA0_SIZE) +#define BF_BCH_FLASH0LAYOUT0_DATA0_SIZE(v) \ + (((v)<< BP_BCH_FLASH0LAYOUT0_DATA0_SIZE)\ + & BM_BCH_FLASH0LAYOUT0_DATA0_SIZE) + +/*======================================================================== ====*/ +#define HW_BCH_FLASH0LAYOUT1 0x00000090 + +#define BP_BCH_FLASH0LAYOUT1_PAGE_SIZE 16 +#define BM_BCH_FLASH0LAYOUT1_PAGE_SIZE \ + (0xffff<< BP_BCH_FLASH0LAYOUT1_PAGE_SIZE) +#define BF_BCH_FLASH0LAYOUT1_PAGE_SIZE(v) \ + (((v)<< BP_BCH_FLASH0LAYOUT1_PAGE_SIZE) \ + & BM_BCH_FLASH0LAYOUT1_PAGE_SIZE) + +#define BP_BCH_FLASH0LAYOUT1_ECCN 12 +#define BM_BCH_FLASH0LAYOUT1_ECCN (0xf<< BP_BCH_FLASH0LAYOUT1_ECCN) +#define BF_BCH_FLASH0LAYOUT1_ECCN(v) \ + (((v)<< BP_BCH_FLASH0LAYOUT1_ECCN)& BM_BCH_FLASH0LAYOUT1_ECCN) + +#define BP_BCH_FLASH0LAYOUT1_DATAN_SIZE 0 +#define BM_BCH_FLASH0LAYOUT1_DATAN_SIZE \ + (0xfff<< BP_BCH_FLASH0LAYOUT1_DATAN_SIZE) +#define BF_BCH_FLASH0LAYOUT1_DATAN_SIZE(v) \ + (((v)<< BP_BCH_FLASH0LAYOUT1_DATAN_SIZE) \ + & BM_BCH_FLASH0LAYOUT1_DATAN_SIZE) +#endifdiff --git a/drivers/mtd/nand/gpmi-nand/gpmi-lib.cb/drivers/mtd/nand/gpmi-nand/gpmi-lib.c new file mode 100644 index 0000000..1368842--- /dev/null +++ b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c@@ -0,0 +1,978 @@ +/* + * Freescale GPMI NAND Flash Driver + * + * Copyright (C) 2008-2011 Freescale Semiconductor, Inc. + * Copyright (C) 2008 Embedded Alley Solutions, Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ +#include "gpmi-nand.h" +#include "gpmi-regs.h" +#include "bch-regs.h" + +struct timing_threshod timing_default_threshold = { + .max_data_setup_cycles = (BM_GPMI_TIMING0_DATA_SETUP>> + BP_GPMI_TIMING0_DATA_SETUP), + .internal_data_setup_in_ns = 0, + .max_sample_delay_factor = (BM_GPMI_CTRL1_RDN_DELAY>> + BP_GPMI_CTRL1_RDN_DELAY), + .max_dll_clock_period_in_ns = 32, + .max_dll_delay_in_ns = 16, +}; + +int gpmi_init(struct gpmi_nand_data *this) +{ + struct resources *r =&this->resources; + int ret; + + ret = clk_enable(r->clock); + if (ret) + goto err_out; + ret = mxs_reset_block(r->gpmi_regs); + if (ret) + goto err_out; + + /* Choose NAND mode. */ + writel(BM_GPMI_CTRL1_GPMI_MODE, r->gpmi_regs + HW_GPMI_CTRL1_CLR); + + /* Set the IRQ polarity. */ + writel(BM_GPMI_CTRL1_ATA_IRQRDY_POLARITY, + r->gpmi_regs + HW_GPMI_CTRL1_SET); + + /* Disable Write-Protection. */ + writel(BM_GPMI_CTRL1_DEV_RESET, r->gpmi_regs + HW_GPMI_CTRL1_SET); + + /* Select BCH ECC. */ + writel(BM_GPMI_CTRL1_BCH_MODE, r->gpmi_regs + HW_GPMI_CTRL1_SET); + + clk_disable(r->clock); + return 0; +err_out: + return ret; +} + +/* This is very useful! */Really? Cool, what for ? btw. this should really be enclosed in some #ifdef debug or whatnot.
Yes, it shows the register contents when DMA timeout occurs. this routine is called only when error occurs.
quoted
+void gpmi_show_regs(struct gpmi_nand_data *this) +{ + struct resources *r =&this->resources; + u32 reg; + int i; + int n; + + n = HW_GPMI_DEBUG / 0x10 + 1; + + pr_info("-------------- Show GPMI registers ----------\n"); + for (i = 0; i<= n; i++) { + reg = readl(r->gpmi_regs + i * 0x10); + pr_info("offset 0x%.3x : 0x%.8x\n", i * 0x10, reg); + } + pr_info("-------------- Show GPMI registers end ----------\n"); +} + +/* Configures the geometry for BCH. */ +int bch_set_geometry(struct gpmi_nand_data *this) +{ + struct resources *r =&this->resources; + struct bch_geometry *bch_geo =&this->bch_geometry; + unsigned int block_count; + unsigned int block_size; + unsigned int metadata_size; + unsigned int ecc_strength; + unsigned int page_size; + int ret; + + if (common_nfc_set_geometry(this)) + return !0; + + block_count = bch_geo->ecc_chunk_count - 1; + block_size = bch_geo->ecc_chunk_size_in_bytes; + metadata_size = bch_geo->metadata_size_in_bytes; + ecc_strength = bch_geo->ecc_strength>> 1; + page_size = bch_geo->page_size_in_bytes; + + ret = clk_enable(r->clock); + if (ret) + goto err_out; + ret = mxs_reset_block(r->bch_regs); + if (ret) + goto err_out; + + /* Configure layout 0. */ + writel(BF_BCH_FLASH0LAYOUT0_NBLOCKS(block_count) + | BF_BCH_FLASH0LAYOUT0_META_SIZE(metadata_size) + | BF_BCH_FLASH0LAYOUT0_ECC0(ecc_strength) + | BF_BCH_FLASH0LAYOUT0_DATA0_SIZE(block_size), + r->bch_regs + HW_BCH_FLASH0LAYOUT0); + + writel(BF_BCH_FLASH0LAYOUT1_PAGE_SIZE(page_size) + | BF_BCH_FLASH0LAYOUT1_ECCN(ecc_strength) + | BF_BCH_FLASH0LAYOUT1_DATAN_SIZE(block_size), + r->bch_regs + HW_BCH_FLASH0LAYOUT1); + + /* Set *all* chip selects to use layout 0. */ + writel(0, r->bch_regs + HW_BCH_LAYOUTSELECT); + + /* Enable interrupts. */ + writel(BM_BCH_CTRL_COMPLETE_IRQ_EN, + r->bch_regs + HW_BCH_CTRL_SET); + + clk_disable(r->clock); + return 0; +err_out: + return ret; +} + +/* + * ns_to_cycles - Converts time in nanoseconds to cycles. + * + * @ntime: The time, in nanoseconds. + * @period: The cycle period, in nanoseconds. + * @min: The minimum allowable number of cycles. + */ +static unsigned int ns_to_cycles(unsigned int time, + unsigned int period, unsigned int min) +{ + unsigned int k; + + /* + * Compute the minimum number of cycles that entirely contain the + * given time. + */ + k = (time + period - 1) / period; + return max(k, min); +} + +/* + * gpmi_compute_hardware_timing - Apply timing to current hardware conditions. + * + * @this: Per-device data. + * @hardware_timing: A pointer to a hardware timing structure that will receive + * the results of our calculations. + */ +static int gpmi_nfc_compute_hardware_timing(struct gpmi_nand_data *this, + struct gpmi_nfc_hardware_timing *hw) +{ + struct gpmi_nand_platform_data *pdata = this->pdata; + struct timing_threshod *nfc =&timing_default_threshold; + struct nand_chip *nand =&this->mil.nand; + struct nand_timing target = this->timing; + bool improved_timing_is_available; + unsigned long clock_frequency_in_hz; + unsigned int clock_period_in_ns; + bool dll_use_half_periods; + unsigned int dll_delay_shift; + unsigned int max_sample_delay_in_ns; + unsigned int address_setup_in_cycles; + unsigned int data_setup_in_ns; + unsigned int data_setup_in_cycles; + unsigned int data_hold_in_cycles; + int ideal_sample_delay_in_ns; + unsigned int sample_delay_factor; + int tEYE; + unsigned int min_prop_delay_in_ns = pdata->min_prop_delay_in_ns; + unsigned int max_prop_delay_in_ns = pdata->max_prop_delay_in_ns; + + /* + * If there are multiple chips, we need to relax the timings to allow + * for signal distortion due to higher capacitance. + */ + if (nand->numchips> 2) { + target.data_setup_in_ns += 10; + target.data_hold_in_ns += 10; + target.address_setup_in_ns += 10; + } else if (nand->numchips> 1) { + target.data_setup_in_ns += 5; + target.data_hold_in_ns += 5; + target.address_setup_in_ns += 5; + } + + /* Check if improved timing information is available. */ + improved_timing_is_available = + (target.tREA_in_ns>= 0)&& + (target.tRLOH_in_ns>= 0)&& + (target.tRHOH_in_ns>= 0) ; + + /* Inspect the clock. */ + clock_frequency_in_hz = nfc->clock_frequency_in_hz; + clock_period_in_ns = 1000000000 / clock_frequency_in_hz; + + /* + * The NFC quantizes setup and hold parameters in terms of clock cycles. + * Here, we quantize the setup and hold timing parameters to the + * next-highest clock period to make sure we apply at least the + * specified times. + * + * For data setup and data hold, the hardware interprets a value of zero + * as the largest possible delay. This is not what's intended by a zero + * in the input parameter, so we impose a minimum of one cycle. + */ + data_setup_in_cycles = ns_to_cycles(target.data_setup_in_ns, + clock_period_in_ns, 1); + data_hold_in_cycles = ns_to_cycles(target.data_hold_in_ns, + clock_period_in_ns, 1); + address_setup_in_cycles = ns_to_cycles(target.address_setup_in_ns, + clock_period_in_ns, 0); + + /* + * The clock's period affects the sample delay in a number of ways: + * + * (1) The NFC HAL tells us the maximum clock period the sample delay + * DLL can tolerate. If the clock period is greater than half that + * maximum, we must configure the DLL to be driven by half periods. + * + * (2) We need to convert from an ideal sample delay, in ns, to a + * "sample delay factor," which the NFC uses. This factor depends on + * whether we're driving the DLL with full or half periods. + * Paraphrasing the reference manual: + * + * AD = SDF x 0.125 x RP + * + * where: + * + * AD is the applied delay, in ns. + * SDF is the sample delay factor, which is dimensionless. + * RP is the reference period, in ns, which is a full clock period + * if the DLL is being driven by full periods, or half that if + * the DLL is being driven by half periods. + * + * Let's re-arrange this in a way that's more useful to us: + * + * 8 + * SDF = AD x ---- + * RP + * + * The reference period is either the clock period or half that, so this + * is: + * + * 8 AD x DDF + * SDF = AD x ----- = -------- + * f x P P + * + * where: + * + * f is 1 or 1/2, depending on how we're driving the DLL. + * P is the clock period. + * DDF is the DLL Delay Factor, a dimensionless value that + * incorporates all the constants in the conversion. + * + * DDF will be either 8 or 16, both of which are powers of two. We can + * reduce the cost of this conversion by using bit shifts instead of + * multiplication or division. Thus: + * + * AD<< DDS + * SDF = --------- + * P + * + * or + * + * AD = (SDF>> DDS) x P + * + * where: + * + * DDS is the DLL Delay Shift, the logarithm to base 2 of the DDF. + */ + if (clock_period_in_ns> (nfc->max_dll_clock_period_in_ns>> 1)) { + dll_use_half_periods = true; + dll_delay_shift = 3 + 1; + } else { + dll_use_half_periods = false; + dll_delay_shift = 3; + } + + /* + * Compute the maximum sample delay the NFC allows, under current + * conditions. If the clock is running too slowly, no sample delay is + * possible. + */ + if (clock_period_in_ns> nfc->max_dll_clock_period_in_ns) + max_sample_delay_in_ns = 0; + else { + /* + * Compute the delay implied by the largest sample delay factor + * the NFC allows. + */ + max_sample_delay_in_ns = + (nfc->max_sample_delay_factor * clock_period_in_ns)>> + dll_delay_shift; + + /* + * Check if the implied sample delay larger than the NFC + * actually allows. + */ + if (max_sample_delay_in_ns> nfc->max_dll_delay_in_ns) + max_sample_delay_in_ns = nfc->max_dll_delay_in_ns; + } + + /* + * Check if improved timing information is available. If not, we have to + * use a less-sophisticated algorithm. + */ + if (!improved_timing_is_available) { + /* + * Fold the read setup time required by the NFC into the ideal + * sample delay. + */ + ideal_sample_delay_in_ns = target.gpmi_sample_delay_in_ns + + nfc->internal_data_setup_in_ns; + + /* + * The ideal sample delay may be greater than the maximum + * allowed by the NFC. If so, we can trade off sample delay time + * for more data setup time. + * + * In each iteration of the following loop, we add a cycle to + * the data setup time and subtract a corresponding amount from + * the sample delay until we've satisified the constraints or + * can't do any better. + */ + while ((ideal_sample_delay_in_ns> max_sample_delay_in_ns)&& + (data_setup_in_cycles< nfc->max_data_setup_cycles)) { + + data_setup_in_cycles++; + ideal_sample_delay_in_ns -= clock_period_in_ns; + + if (ideal_sample_delay_in_ns< 0) + ideal_sample_delay_in_ns = 0; + + } + + /* + * Compute the sample delay factor that corresponds most closely + * to the ideal sample delay. If the result is too large for the + * NFC, use the maximum value. + * + * Notice that we use the ns_to_cycles function to compute the + * sample delay factor. We do this because the form of the + * computation is the same as that for calculating cycles. + */ + sample_delay_factor = + ns_to_cycles( + ideal_sample_delay_in_ns<< dll_delay_shift, + clock_period_in_ns, 0); + + if (sample_delay_factor> nfc->max_sample_delay_factor) + sample_delay_factor = nfc->max_sample_delay_factor; + + /* Skip to the part where we return our results. */ + goto return_results; + } + + /* + * If control arrives here, we have more detailed timing information, + * so we can use a better algorithm. + */ + + /* + * Fold the read setup time required by the NFC into the maximum + * propagation delay. + */ + max_prop_delay_in_ns += nfc->internal_data_setup_in_ns; + + /* + * Earlier, we computed the number of clock cycles required to satisfy + * the data setup time. Now, we need to know the actual nanoseconds. + */ + data_setup_in_ns = clock_period_in_ns * data_setup_in_cycles; + + /* + * Compute tEYE, the width of the data eye when reading from the NAND + * Flash. The eye width is fundamentally determined by the data setup + * time, perturbed by propagation delays and some characteristics of the + * NAND Flash device. + * + * start of the eye = max_prop_delay + tREA + * end of the eye = min_prop_delay + tRHOH + data_setup + */ + tEYE = (int)min_prop_delay_in_ns + (int)target.tRHOH_in_ns + + (int)data_setup_in_ns; + + tEYE -= (int)max_prop_delay_in_ns + (int)target.tREA_in_ns; + + /* + * The eye must be open. If it's not, we can try to open it by + * increasing its main forcer, the data setup time. + * + * In each iteration of the following loop, we increase the data setup + * time by a single clock cycle. We do this until either the eye is + * open or we run into NFC limits. + */ + while ((tEYE<= 0)&& + (data_setup_in_cycles< nfc->max_data_setup_cycles)) { + /* Give a cycle to data setup. */ + data_setup_in_cycles++; + /* Synchronize the data setup time with the cycles. */ + data_setup_in_ns += clock_period_in_ns; + /* Adjust tEYE accordingly. */ + tEYE += clock_period_in_ns; + } + + /* + * When control arrives here, the eye is open. The ideal time to sample + * the data is in the center of the eye: + * + * end of the eye + start of the eye + * --------------------------------- - data_setup + * 2 + * + * After some algebra, this simplifies to the code immediately below. + */ + ideal_sample_delay_in_ns = + ((int)max_prop_delay_in_ns + + (int)target.tREA_in_ns + + (int)min_prop_delay_in_ns + + (int)target.tRHOH_in_ns - + (int)data_setup_in_ns)>> 1; + + /* + * The following figure illustrates some aspects of a NAND Flash read: + * + * + * __ _____________________________________ + * RDN \_________________/ + * + *<---- tEYE -----> + * /-----------------\ + * Read Data ----------------------------< >--------- + * \-----------------/ + * ^ ^ ^ ^ + * | | | | + * |<--Data Setup -->|<--Delay Time -->| | + * | | | | + * | | | + * | |<-- Quantized Delay Time -->| + * | | | + * + * + * We have some issues we must now address: + * + * (1) The *ideal* sample delay time must not be negative. If it is, we + * jam it to zero. + * + * (2) The *ideal* sample delay time must not be greater than that + * allowed by the NFC. If it is, we can increase the data setup + * time, which will reduce the delay between the end of the data + * setup and the center of the eye. It will also make the eye + * larger, which might help with the next issue... + * + * (3) The *quantized* sample delay time must not fall either before the + * eye opens or after it closes (the latter is the problem + * illustrated in the above figure). + */ + + /* Jam a negative ideal sample delay to zero. */ + if (ideal_sample_delay_in_ns< 0) + ideal_sample_delay_in_ns = 0; + + /* + * Extend the data setup as needed to reduce the ideal sample delay + * below the maximum permitted by the NFC. + */ + while ((ideal_sample_delay_in_ns> max_sample_delay_in_ns)&& + (data_setup_in_cycles< nfc->max_data_setup_cycles)) { + + /* Give a cycle to data setup. */ + data_setup_in_cycles++; + /* Synchronize the data setup time with the cycles. */ + data_setup_in_ns += clock_period_in_ns; + /* Adjust tEYE accordingly. */ + tEYE += clock_period_in_ns; + + /* + * Decrease the ideal sample delay by one half cycle, to keep it + * in the middle of the eye. + */ + ideal_sample_delay_in_ns -= (clock_period_in_ns>> 1); + + /* Jam a negative ideal sample delay to zero. */ + if (ideal_sample_delay_in_ns< 0) + ideal_sample_delay_in_ns = 0; + } + + /* + * Compute the sample delay factor that corresponds to the ideal sample + * delay. If the result is too large, then use the maximum allowed + * value. + * + * Notice that we use the ns_to_cycles function to compute the sample + * delay factor. We do this because the form of the computation is the + * same as that for calculating cycles. + */ + sample_delay_factor = + ns_to_cycles(ideal_sample_delay_in_ns<< dll_delay_shift, + clock_period_in_ns, 0); + + if (sample_delay_factor> nfc->max_sample_delay_factor) + sample_delay_factor = nfc->max_sample_delay_factor; + + /* + * These macros conveniently encapsulate a computation we'll use to + * continuously evaluate whether or not the data sample delay is inside + * the eye. + */ + #define IDEAL_DELAY ((int) ideal_sample_delay_in_ns) + + #define QUANTIZED_DELAY \ + ((int) ((sample_delay_factor * clock_period_in_ns)>> \ + dll_delay_shift)) + + #define DELAY_ERROR (abs(QUANTIZED_DELAY - IDEAL_DELAY)) + + #define SAMPLE_IS_NOT_WITHIN_THE_EYE (DELAY_ERROR> (tEYE>> 1)) + + /* + * While the quantized sample time falls outside the eye, reduce the + * sample delay or extend the data setup to move the sampling point back + * toward the eye. Do not allow the number of data setup cycles to + * exceed the maximum allowed by the NFC. + */ + while (SAMPLE_IS_NOT_WITHIN_THE_EYE&& + (data_setup_in_cycles< nfc->max_data_setup_cycles)) { + /* + * If control arrives here, the quantized sample delay falls + * outside the eye. Check if it's before the eye opens, or after + * the eye closes. + */ + if (QUANTIZED_DELAY> IDEAL_DELAY) { + /* + * If control arrives here, the quantized sample delay + * falls after the eye closes. Decrease the quantized + * delay time and then go back to re-evaluate. + */ + if (sample_delay_factor != 0) + sample_delay_factor--; + continue; + } + + /* + * If control arrives here, the quantized sample delay falls + * before the eye opens. Shift the sample point by increasing + * data setup time. This will also make the eye larger. + */ + + /* Give a cycle to data setup. */ + data_setup_in_cycles++; + /* Synchronize the data setup time with the cycles. */ + data_setup_in_ns += clock_period_in_ns; + /* Adjust tEYE accordingly. */ + tEYE += clock_period_in_ns; + + /* + * Decrease the ideal sample delay by one half cycle, to keep it + * in the middle of the eye. + */ + ideal_sample_delay_in_ns -= (clock_period_in_ns>> 1); + + /* ...and one less period for the delay time. */ + ideal_sample_delay_in_ns -= clock_period_in_ns; + + /* Jam a negative ideal sample delay to zero. */ + if (ideal_sample_delay_in_ns< 0) + ideal_sample_delay_in_ns = 0; + + /* + * We have a new ideal sample delay, so re-compute the quantized + * delay. + */ + sample_delay_factor = + ns_to_cycles( + ideal_sample_delay_in_ns<< dll_delay_shift, + clock_period_in_ns, 0); + + if (sample_delay_factor> nfc->max_sample_delay_factor) + sample_delay_factor = nfc->max_sample_delay_factor; + } + + /* Control arrives here when we're ready to return our results. */ +return_results: + hw->data_setup_in_cycles = data_setup_in_cycles; + hw->data_hold_in_cycles = data_hold_in_cycles; + hw->address_setup_in_cycles = address_setup_in_cycles; + hw->use_half_periods = dll_use_half_periods; + hw->sample_delay_factor = sample_delay_factor; + + /* Return success. */ + return 0; +} + +/* Begin the I/O */ +void gpmi_begin(struct gpmi_nand_data *this) +{ + struct resources *r =&this->resources; + struct timing_threshod *nfc =&timing_default_threshold; + unsigned char *gpmi_regs = r->gpmi_regs; + unsigned int clock_period_in_ns; + uint32_t reg; + unsigned int dll_wait_time_in_us; + struct gpmi_nfc_hardware_timing hw; + int ret; + + /* Enable the clock. */ + ret = clk_enable(r->clock); + if (ret) { + pr_info("We failed in enable the clk\n"); + goto err_out; + } + + /* set ready/busy timeout */ + writel(0x500<< 16, gpmi_regs + HW_GPMI_TIMING1); + + /* Get the timing information we need. */ + nfc->clock_frequency_in_hz = clk_get_rate(r->clock); + clock_period_in_ns = 1000000000 / nfc->clock_frequency_in_hz; + + gpmi_nfc_compute_hardware_timing(this,&hw); + + /* Set up all the simple timing parameters. */ + reg = BF_GPMI_TIMING0_ADDRESS_SETUP(hw.address_setup_in_cycles) | + BF_GPMI_TIMING0_DATA_HOLD(hw.data_hold_in_cycles) | + BF_GPMI_TIMING0_DATA_SETUP(hw.data_setup_in_cycles) ; + + writel(reg, gpmi_regs + HW_GPMI_TIMING0); + + /* + * HEY - PAY ATTENTION!Please fix this comment and pay attention to other comments ;-)
ok :) thanks Huang Shijie