[PATCH 7/7] mtd: mxs_nand: Support EDO mode for imx8mn architecture
Dario Binacchi
dario.binacchi at amarulasolutions.com
Wed Sep 28 10:45:09 CEST 2022
From: Michael Trimarchi <michael at amarulasolutions.com>
Add support for imx8mn architecture in order to run the NAND
in fast edo mode.
Signed-off-by: Michael Trimarchi <michael at amarulasolutions.com>
Signed-off-by: Dario Binacchi <dario.binacchi at amarulasolutions.com>
---
drivers/mtd/nand/raw/mxs_nand.c | 200 +++++++++++++++++++++++++++++
drivers/mtd/nand/raw/mxs_nand_dt.c | 66 ++++++----
include/mxs_nand.h | 3 +
3 files changed, 242 insertions(+), 27 deletions(-)
diff --git a/drivers/mtd/nand/raw/mxs_nand.c b/drivers/mtd/nand/raw/mxs_nand.c
index 7893e9d7e343..65eab4c8088a 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;
diff --git a/drivers/mtd/nand/raw/mxs_nand_dt.c b/drivers/mtd/nand/raw/mxs_nand_dt.c
index 94ee7ed9ec83..a922a22b2730 100644
--- a/drivers/mtd/nand/raw/mxs_nand_dt.c
+++ b/drivers/mtd/nand/raw/mxs_nand_dt.c
@@ -22,22 +22,27 @@
struct mxs_nand_dt_data {
unsigned int max_ecc_strength_supported;
+ int max_chain_delay; /* See the async EDO mode */
};
static const struct mxs_nand_dt_data mxs_nand_imx6q_data = {
.max_ecc_strength_supported = 40,
+ .max_chain_delay = 12000,
};
static const struct mxs_nand_dt_data mxs_nand_imx6sx_data = {
.max_ecc_strength_supported = 62,
+ .max_chain_delay = 12000,
};
static const struct mxs_nand_dt_data mxs_nand_imx7d_data = {
.max_ecc_strength_supported = 62,
+ .max_chain_delay = 12000,
};
static const struct mxs_nand_dt_data mxs_nand_imx8qxp_data = {
.max_ecc_strength_supported = 62,
+ .max_chain_delay = 12000,
};
static const struct udevice_id mxs_nand_dt_ids[] = {
@@ -72,8 +77,10 @@ static int mxs_nand_dt_probe(struct udevice *dev)
int ret;
data = (void *)dev_get_driver_data(dev);
- if (data)
+ if (data) {
info->max_ecc_strength_supported = data->max_ecc_strength_supported;
+ info->max_chain_delay = data->max_chain_delay;
+ }
info->dev = dev;
@@ -92,44 +99,49 @@ static int mxs_nand_dt_probe(struct udevice *dev)
info->use_minimum_ecc = dev_read_bool(dev, "fsl,use-minimum-ecc");
- if (IS_ENABLED(CONFIG_CLK) && IS_ENABLED(CONFIG_IMX8)) {
+ if (IS_ENABLED(CONFIG_CLK) &&
+ (IS_ENABLED(CONFIG_IMX8) || IS_ENABLED(CONFIG_IMX8M))) {
/* Assigned clock already set clock */
struct clk gpmi_clk;
- ret = clk_get_by_name(dev, "gpmi_io", &gpmi_clk);
- if (ret < 0) {
+ info->gpmi_clk = devm_clk_get(dev, "gpmi_io");
+
+ if (IS_ERR(info->gpmi_clk)) {
+ ret = PTR_ERR(info->gpmi_clk);
debug("Can't get gpmi io clk: %d\n", ret);
return ret;
}
- ret = clk_enable(&gpmi_clk);
+ ret = clk_enable(info->gpmi_clk);
if (ret < 0) {
debug("Can't enable gpmi io clk: %d\n", ret);
return ret;
}
- ret = clk_get_by_name(dev, "gpmi_apb", &gpmi_clk);
- if (ret < 0) {
- debug("Can't get gpmi_apb clk: %d\n", ret);
- return ret;
- }
-
- ret = clk_enable(&gpmi_clk);
- if (ret < 0) {
- debug("Can't enable gpmi_apb clk: %d\n", ret);
- return ret;
- }
-
- ret = clk_get_by_name(dev, "gpmi_bch", &gpmi_clk);
- if (ret < 0) {
- debug("Can't get gpmi_bch clk: %d\n", ret);
- return ret;
- }
-
- ret = clk_enable(&gpmi_clk);
- if (ret < 0) {
- debug("Can't enable gpmi_bch clk: %d\n", ret);
- return ret;
+ if (IS_ENABLED(CONFIG_IMX8)) {
+ ret = clk_get_by_name(dev, "gpmi_apb", &gpmi_clk);
+ if (ret < 0) {
+ debug("Can't get gpmi_apb clk: %d\n", ret);
+ return ret;
+ }
+
+ ret = clk_enable(&gpmi_clk);
+ if (ret < 0) {
+ debug("Can't enable gpmi_apb clk: %d\n", ret);
+ return ret;
+ }
+
+ ret = clk_get_by_name(dev, "gpmi_bch", &gpmi_clk);
+ if (ret < 0) {
+ debug("Can't get gpmi_bch clk: %d\n", ret);
+ return ret;
+ }
+
+ ret = clk_enable(&gpmi_clk);
+ if (ret < 0) {
+ debug("Can't enable gpmi_bch clk: %d\n", ret);
+ return ret;
+ }
}
ret = clk_get_by_name(dev, "gpmi_bch_apb", &gpmi_clk);
diff --git a/include/mxs_nand.h b/include/mxs_nand.h
index 741dc8734eae..bb5b84b8c26e 100644
--- a/include/mxs_nand.h
+++ b/include/mxs_nand.h
@@ -12,6 +12,7 @@
#include <asm/cache.h>
#include <nand.h>
#include <asm/mach-imx/dma.h>
+#include <clk.h>
/**
* @gf_len: The length of Galois Field. (e.g., 13 or 14)
@@ -43,6 +44,7 @@ struct mxs_nand_info {
struct nand_chip chip;
struct udevice *dev;
unsigned int max_ecc_strength_supported;
+ int max_chain_delay;
bool use_minimum_ecc;
int cur_chip;
@@ -59,6 +61,7 @@ struct mxs_nand_info {
struct mxs_gpmi_regs *gpmi_regs;
struct mxs_bch_regs *bch_regs;
+ struct clk *gpmi_clk;
/* Functions with altered behaviour */
int (*hooked_read_oob)(struct mtd_info *mtd,
--
2.32.0
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