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Subject[PATCH 3/3] mtd: rawnand: stm32_fmc2: add manual mode
Date
From: Christophe Kerello <christophe.kerello@st.com>

This patch adds the manual mode, a basic mode that do not need
any DMA channels. This mode is also useful for debug purpose.

Signed-off-by: Christophe Kerello <christophe.kerello@st.com>
---
drivers/mtd/nand/raw/stm32_fmc2_nand.c | 271 +++++++++++++++++++++++++++++++--
1 file changed, 261 insertions(+), 10 deletions(-)

diff --git a/drivers/mtd/nand/raw/stm32_fmc2_nand.c b/drivers/mtd/nand/raw/stm32_fmc2_nand.c
index dd5762a..c74df81 100644
--- a/drivers/mtd/nand/raw/stm32_fmc2_nand.c
+++ b/drivers/mtd/nand/raw/stm32_fmc2_nand.c
@@ -204,6 +204,12 @@ enum stm32_fmc2_ecc {
FMC2_ECC_BCH8 = 8
};

+enum stm32_fmc2_irq_state {
+ FMC2_IRQ_UNKNOWN = 0,
+ FMC2_IRQ_BCH,
+ FMC2_IRQ_SEQ
+};
+
struct stm32_fmc2_timings {
u8 tclr;
u8 tar;
@@ -225,6 +231,7 @@ struct stm32_fmc2 {
phys_addr_t io_phys_addr;
phys_addr_t data_phys_addr[FMC2_MAX_CE];
struct clk *clk;
+ u8 irq_state;

struct dma_chan *dma_tx_ch;
struct dma_chan *dma_rx_ch;
@@ -252,6 +259,8 @@ static inline void stm32_fmc2_enable_seq_irq(struct stm32_fmc2 *fmc2)

csqier |= FMC2_CSQIER_TCIE;

+ fmc2->irq_state = FMC2_IRQ_SEQ;
+
writel_relaxed(csqier, fmc2->io_base + FMC2_CSQIER);
}

@@ -263,6 +272,8 @@ static inline void stm32_fmc2_disable_seq_irq(struct stm32_fmc2 *fmc2)
csqier &= ~FMC2_CSQIER_TCIE;

writel_relaxed(csqier, fmc2->io_base + FMC2_CSQIER);
+
+ fmc2->irq_state = FMC2_IRQ_UNKNOWN;
}

/* Clear irq sources in case of the sequencer is used */
@@ -271,6 +282,40 @@ static inline void stm32_fmc2_clear_seq_irq(struct stm32_fmc2 *fmc2)
writel_relaxed(FMC2_CSQICR_CLEAR_IRQ, fmc2->io_base + FMC2_CSQICR);
}

+/* Enable irq sources in case of bch is used */
+static inline void stm32_fmc2_enable_bch_irq(struct stm32_fmc2 *fmc2, int mode)
+{
+ u32 bchier = readl_relaxed(fmc2->io_base + FMC2_BCHIER);
+
+ if (mode == NAND_ECC_WRITE)
+ bchier |= FMC2_BCHIER_EPBRIE;
+ else
+ bchier |= FMC2_BCHIER_DERIE;
+
+ fmc2->irq_state = FMC2_IRQ_BCH;
+
+ writel_relaxed(bchier, fmc2->io_base + FMC2_BCHIER);
+}
+
+/* Disable irq sources in case of bch is used */
+static inline void stm32_fmc2_disable_bch_irq(struct stm32_fmc2 *fmc2)
+{
+ u32 bchier = readl_relaxed(fmc2->io_base + FMC2_BCHIER);
+
+ bchier &= ~FMC2_BCHIER_DERIE;
+ bchier &= ~FMC2_BCHIER_EPBRIE;
+
+ writel_relaxed(bchier, fmc2->io_base + FMC2_BCHIER);
+
+ fmc2->irq_state = FMC2_IRQ_UNKNOWN;
+}
+
+/* Clear irq sources in case of bch is used */
+static inline void stm32_fmc2_clear_bch_irq(struct stm32_fmc2 *fmc2)
+{
+ writel_relaxed(FMC2_BCHICR_CLEAR_IRQ, fmc2->io_base + FMC2_BCHICR);
+}
+
/* Select function */
static void stm32_fmc2_select_chip(struct nand_chip *chip, int chipnr)
{
@@ -303,6 +348,35 @@ static void stm32_fmc2_select_chip(struct nand_chip *chip, int chipnr)
}

/*
+ * Enable ecc logic and reset syndrome/parity bits previously calculated
+ * Syndrome/parity bits is cleared by setting the ECCEN bit to 0
+ */
+static void stm32_fmc2_hwctl(struct nand_chip *chip, int mode)
+{
+ struct stm32_fmc2 *fmc2 = nand_get_controller_data(chip);
+ u32 pcr = readl_relaxed(fmc2->io_base + FMC2_PCR);
+
+ pcr &= ~FMC2_PCR_ECCEN;
+ writel_relaxed(pcr, fmc2->io_base + FMC2_PCR);
+
+ if (chip->ecc.strength != FMC2_ECC_HAM) {
+ if (mode == NAND_ECC_WRITE)
+ pcr |= FMC2_PCR_WEN;
+ else
+ pcr &= ~FMC2_PCR_WEN;
+ writel_relaxed(pcr, fmc2->io_base + FMC2_PCR);
+
+ reinit_completion(&fmc2->complete);
+ stm32_fmc2_clear_bch_irq(fmc2);
+ stm32_fmc2_enable_bch_irq(fmc2, mode);
+ }
+
+ pcr = readl_relaxed(fmc2->io_base + FMC2_PCR);
+ pcr |= FMC2_PCR_ECCEN;
+ writel_relaxed(pcr, fmc2->io_base + FMC2_PCR);
+}
+
+/*
* ECC HAMMING calculation
* ECC is 3 bytes for 512 bytes of data (supports error correction up to
* max of 1-bit)
@@ -314,6 +388,27 @@ static inline void stm32_fmc2_ham_set_ecc(const u32 ecc_sta, u8 *ecc)
ecc[2] = ecc_sta >> 16;
}

+static int stm32_fmc2_ham_calculate(struct nand_chip *chip, const uint8_t *data,
+ uint8_t *ecc)
+{
+ struct stm32_fmc2 *fmc2 = nand_get_controller_data(chip);
+ u32 sr, heccr;
+ int ret;
+
+ ret = readl_relaxed_poll_timeout(fmc2->io_base + FMC2_SR,
+ sr, sr & FMC2_SR_NWRF, 10, 1000);
+ if (ret) {
+ dev_err(fmc2->dev, "ham timeout\n");
+ return ret;
+ }
+
+ heccr = readl_relaxed(fmc2->io_base + FMC2_HECCR);
+
+ stm32_fmc2_ham_set_ecc(heccr, ecc);
+
+ return 0;
+}
+
static int stm32_fmc2_ham_correct(struct nand_chip *chip, uint8_t *dat,
uint8_t *read_ecc, uint8_t *calc_ecc)
{
@@ -366,6 +461,53 @@ static int stm32_fmc2_ham_correct(struct nand_chip *chip, uint8_t *dat,
return 1;
}

+/*
+ * ECC BCH calculation and correction
+ * ECC is 7/13 bytes for 512 bytes of data (supports error correction up to
+ * max of 4-bit/8-bit)
+ */
+static int stm32_fmc2_bch_calculate(struct nand_chip *chip, const uint8_t *data,
+ uint8_t *ecc)
+{
+ struct stm32_fmc2 *fmc2 = nand_get_controller_data(chip);
+ u32 bchpbr;
+
+ /* Wait until the BCH code is ready */
+ if (!wait_for_completion_timeout(&fmc2->complete,
+ msecs_to_jiffies(1000))) {
+ dev_err(fmc2->dev, "bch timeout\n");
+ stm32_fmc2_disable_bch_irq(fmc2);
+ return -ETIMEDOUT;
+ }
+
+ /* Read parity bits */
+ bchpbr = readl_relaxed(fmc2->io_base + FMC2_BCHPBR1);
+ ecc[0] = bchpbr;
+ ecc[1] = bchpbr >> 8;
+ ecc[2] = bchpbr >> 16;
+ ecc[3] = bchpbr >> 24;
+
+ bchpbr = readl_relaxed(fmc2->io_base + FMC2_BCHPBR2);
+ ecc[4] = bchpbr;
+ ecc[5] = bchpbr >> 8;
+ ecc[6] = bchpbr >> 16;
+
+ if (chip->ecc.strength == FMC2_ECC_BCH8) {
+ ecc[7] = bchpbr >> 24;
+
+ bchpbr = readl_relaxed(fmc2->io_base + FMC2_BCHPBR3);
+ ecc[8] = bchpbr;
+ ecc[9] = bchpbr >> 8;
+ ecc[10] = bchpbr >> 16;
+ ecc[11] = bchpbr >> 24;
+
+ bchpbr = readl_relaxed(fmc2->io_base + FMC2_BCHPBR4);
+ ecc[12] = bchpbr;
+ }
+
+ return 0;
+}
+
/* BCH algorithm correction */
static int stm32_fmc2_bch_decode(int eccsize, u8 *dat, u32 *ecc_sta)
{
@@ -406,6 +548,91 @@ static int stm32_fmc2_bch_decode(int eccsize, u8 *dat, u32 *ecc_sta)
return nb_errs;
}

+static int stm32_fmc2_bch_correct(struct nand_chip *chip, uint8_t *dat,
+ uint8_t *read_ecc, uint8_t *calc_ecc)
+{
+ struct stm32_fmc2 *fmc2 = nand_get_controller_data(chip);
+ u32 ecc_sta[5];
+
+ /* Wait until the decoding error is ready */
+ if (!wait_for_completion_timeout(&fmc2->complete,
+ msecs_to_jiffies(1000))) {
+ dev_err(fmc2->dev, "bch timeout\n");
+ stm32_fmc2_disable_bch_irq(fmc2);
+ return -ETIMEDOUT;
+ }
+
+ ecc_sta[0] = readl_relaxed(fmc2->io_base + FMC2_BCHDSR0);
+ ecc_sta[1] = readl_relaxed(fmc2->io_base + FMC2_BCHDSR1);
+ ecc_sta[2] = readl_relaxed(fmc2->io_base + FMC2_BCHDSR2);
+ ecc_sta[3] = readl_relaxed(fmc2->io_base + FMC2_BCHDSR3);
+ ecc_sta[4] = readl_relaxed(fmc2->io_base + FMC2_BCHDSR4);
+
+ return stm32_fmc2_bch_decode(chip->ecc.size, dat, ecc_sta);
+}
+
+static int stm32_fmc2_read_page(struct nand_chip *chip, uint8_t *buf,
+ int oob_required, int page)
+{
+ struct mtd_info *mtd = nand_to_mtd(chip);
+ int ret, i, s, stat, eccsize = chip->ecc.size;
+ int eccbytes = chip->ecc.bytes;
+ int eccsteps = chip->ecc.steps;
+ int eccstrength = chip->ecc.strength;
+ u8 *p = buf;
+ u8 *ecc_calc = chip->ecc.calc_buf;
+ u8 *ecc_code = chip->ecc.code_buf;
+ unsigned int max_bitflips = 0;
+
+ ret = nand_read_page_op(chip, page, 0, NULL, 0);
+ if (ret)
+ return ret;
+
+ for (i = mtd->writesize + FMC2_BBM_LEN, s = 0; s < eccsteps;
+ s++, i += eccbytes, p += eccsize) {
+ chip->ecc.hwctl(chip, NAND_ECC_READ);
+
+ /* Read the nand page sector (512 bytes) */
+ ret = nand_change_read_column_op(chip, s * eccsize, p,
+ eccsize, false);
+ if (ret)
+ return ret;
+
+ /* Read the corresponding ecc bytes */
+ ret = nand_change_read_column_op(chip, i, ecc_code,
+ eccbytes, false);
+ if (ret)
+ return ret;
+
+ /* Correct the data */
+ stat = chip->ecc.correct(chip, p, ecc_code, ecc_calc);
+ if (stat == -EBADMSG)
+ /* Check for empty pages with bitflips */
+ stat = nand_check_erased_ecc_chunk(p, eccsize,
+ ecc_code, eccbytes,
+ NULL, 0,
+ eccstrength);
+
+ if (stat < 0) {
+ mtd->ecc_stats.failed++;
+ } else {
+ mtd->ecc_stats.corrected += stat;
+ max_bitflips = max_t(unsigned int, max_bitflips, stat);
+ }
+ }
+
+ /* Read oob */
+ if (oob_required) {
+ ret = nand_change_read_column_op(chip, mtd->writesize,
+ chip->oob_poi, mtd->oobsize,
+ false);
+ if (ret)
+ return ret;
+ }
+
+ return max_bitflips;
+}
+
/* Sequencer read/write configuration */
static void stm32_fmc2_rw_page_init(struct stm32_fmc2 *fmc2, int page,
int raw, bool write_data)
@@ -817,7 +1044,12 @@ static irqreturn_t stm32_fmc2_irq(int irq, void *dev_id)
{
struct stm32_fmc2 *fmc2 = (struct stm32_fmc2 *)dev_id;

- stm32_fmc2_disable_seq_irq(fmc2);
+ if (fmc2->irq_state == FMC2_IRQ_SEQ)
+ /* Sequencer is used */
+ stm32_fmc2_disable_seq_irq(fmc2);
+ else if (fmc2->irq_state == FMC2_IRQ_BCH)
+ /* BCH is used */
+ stm32_fmc2_disable_bch_irq(fmc2);

complete(&fmc2->complete);

@@ -1297,8 +1529,7 @@ static int stm32_fmc2_dma_setup(struct stm32_fmc2 *fmc2, u8 nbsect)
init_completion(&fmc2->dma_data_complete);
init_completion(&fmc2->dma_ecc_complete);
} else {
- dev_err(fmc2->dev, "rx/tx DMA not defined in the device tree\n");
- return -ENOENT;
+ dev_warn(fmc2->dev, "DMA not defined in the device tree, manual mode is used\n");
}

return 0;
@@ -1309,13 +1540,33 @@ static void stm32_fmc2_nand_callbacks_setup(struct stm32_fmc2 *fmc2)
{
struct nand_chip *chip = &fmc2->chip;

- /* Specific callbacks to read/write a page */
- chip->ecc.correct = stm32_fmc2_ham_correct;
- chip->ecc.write_page = stm32_fmc2_sequencer_write_page;
- chip->ecc.read_page = stm32_fmc2_sequencer_read_page;
- chip->ecc.write_page_raw = stm32_fmc2_sequencer_write_page_raw;
- chip->ecc.read_page_raw = stm32_fmc2_sequencer_read_page_raw;
- chip->options |= NAND_USE_BOUNCE_BUFFER;
+ /*
+ * Specific callbacks to read/write a page depending on
+ * the mode (manual/sequencer) and the algo used (HAMMING, BCH).
+ */
+ if (fmc2->dma_tx_ch && fmc2->dma_rx_ch) {
+ /* DMA => use sequencer mode callbacks */
+ chip->ecc.correct = stm32_fmc2_ham_correct;
+ chip->ecc.write_page = stm32_fmc2_sequencer_write_page;
+ chip->ecc.read_page = stm32_fmc2_sequencer_read_page;
+ chip->ecc.write_page_raw = stm32_fmc2_sequencer_write_page_raw;
+ chip->ecc.read_page_raw = stm32_fmc2_sequencer_read_page_raw;
+ chip->options |= NAND_USE_BOUNCE_BUFFER;
+ } else {
+ /* No DMA => use manual mode callbacks */
+ chip->ecc.hwctl = stm32_fmc2_hwctl;
+ if (chip->ecc.strength == FMC2_ECC_HAM) {
+ /* HAMMING is used */
+ chip->ecc.calculate = stm32_fmc2_ham_calculate;
+ chip->ecc.correct = stm32_fmc2_ham_correct;
+ chip->ecc.options |= NAND_ECC_GENERIC_ERASED_CHECK;
+ } else {
+ /* BCH is used */
+ chip->ecc.calculate = stm32_fmc2_bch_calculate;
+ chip->ecc.correct = stm32_fmc2_bch_correct;
+ chip->ecc.read_page = stm32_fmc2_read_page;
+ }
+ }

/* Specific configurations depending on the algo used */
if (chip->ecc.strength == FMC2_ECC_HAM)
--
1.9.1
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