spi: Add QuadSPI driver for Atmel SAMA5D2

Kernel contains QSPI driver strongly tied to MTD and nor-flash memory.
New spi-mem interface allows usage also other memory types, especially
much larger NAND with SPI interface. This driver works as SPI controller
and is not related to MTD, however can work with NAND-flash or other
peripherals using spi-mem interface.

Suggested-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Piotr Bugalski <bugalski.piotr@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 549 insertions, 0 deletions

diff --git a/drivers/spi/atmel-quadspi.c b/drivers/spi/atmel-quadspi.c
new file mode 100644
index 000000000000..ddc712410812
--- /dev/null
+++ b/drivers/spi/atmel-quadspi.c
@@ -0,0 +1,549 @@
+/*
+ * Driver for Atmel QSPI Controller
+ *
+ * Copyright (C) 2015 Atmel Corporation
+ * Copyright (C) 2018 Cryptera A/S
+ *
+ * Author: Cyrille Pitchen <cyrille.pitchen@atmel.com>
+ * Author: Piotr Bugalski <bugalski.piotr@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ *
+ * This driver is based on drivers/mtd/spi-nor/fsl-quadspi.c from Freescale.
+ */
+
+#include <linux/kernel.h>
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/of.h>
+
+#include <linux/io.h>
+#include <linux/spi/spi-mem.h>
+
+/* QSPI register offsets */
+#define QSPI_CR      0x0000  /* Control Register */
+#define QSPI_MR      0x0004  /* Mode Register */
+#define QSPI_RD      0x0008  /* Receive Data Register */
+#define QSPI_TD      0x000c  /* Transmit Data Register */
+#define QSPI_SR      0x0010  /* Status Register */
+#define QSPI_IER     0x0014  /* Interrupt Enable Register */
+#define QSPI_IDR     0x0018  /* Interrupt Disable Register */
+#define QSPI_IMR     0x001c  /* Interrupt Mask Register */
+#define QSPI_SCR     0x0020  /* Serial Clock Register */
+
+#define QSPI_IAR     0x0030  /* Instruction Address Register */
+#define QSPI_ICR     0x0034  /* Instruction Code Register */
+#define QSPI_IFR     0x0038  /* Instruction Frame Register */
+
+#define QSPI_SMR     0x0040  /* Scrambling Mode Register */
+#define QSPI_SKR     0x0044  /* Scrambling Key Register */
+
+#define QSPI_WPMR    0x00E4  /* Write Protection Mode Register */
+#define QSPI_WPSR    0x00E8  /* Write Protection Status Register */
+
+#define QSPI_VERSION 0x00FC  /* Version Register */
+
+
+/* Bitfields in QSPI_CR (Control Register) */
+#define QSPI_CR_QSPIEN                  BIT(0)
+#define QSPI_CR_QSPIDIS                 BIT(1)
+#define QSPI_CR_SWRST                   BIT(7)
+#define QSPI_CR_LASTXFER                BIT(24)
+
+/* Bitfields in QSPI_MR (Mode Register) */
+#define QSPI_MR_SMM                     BIT(0)
+#define QSPI_MR_LLB                     BIT(1)
+#define QSPI_MR_WDRBT                   BIT(2)
+#define QSPI_MR_SMRM                    BIT(3)
+#define QSPI_MR_CSMODE_MASK             GENMASK(5, 4)
+#define QSPI_MR_CSMODE_NOT_RELOADED     (0 << 4)
+#define QSPI_MR_CSMODE_LASTXFER         (1 << 4)
+#define QSPI_MR_CSMODE_SYSTEMATICALLY   (2 << 4)
+#define QSPI_MR_NBBITS_MASK             GENMASK(11, 8)
+#define QSPI_MR_NBBITS(n)               ((((n) - 8) << 8) & QSPI_MR_NBBITS_MASK)
+#define QSPI_MR_DLYBCT_MASK             GENMASK(23, 16)
+#define QSPI_MR_DLYBCT(n)               (((n) << 16) & QSPI_MR_DLYBCT_MASK)
+#define QSPI_MR_DLYCS_MASK              GENMASK(31, 24)
+#define QSPI_MR_DLYCS(n)                (((n) << 24) & QSPI_MR_DLYCS_MASK)
+
+/* Bitfields in QSPI_SR/QSPI_IER/QSPI_IDR/QSPI_IMR  */
+#define QSPI_SR_RDRF                    BIT(0)
+#define QSPI_SR_TDRE                    BIT(1)
+#define QSPI_SR_TXEMPTY                 BIT(2)
+#define QSPI_SR_OVRES                   BIT(3)
+#define QSPI_SR_CSR                     BIT(8)
+#define QSPI_SR_CSS                     BIT(9)
+#define QSPI_SR_INSTRE                  BIT(10)
+#define QSPI_SR_QSPIENS                 BIT(24)
+
+#define QSPI_SR_CMD_COMPLETED   (QSPI_SR_INSTRE | QSPI_SR_CSR)
+
+/* Bitfields in QSPI_SCR (Serial Clock Register) */
+#define QSPI_SCR_CPOL                   BIT(0)
+#define QSPI_SCR_CPHA                   BIT(1)
+#define QSPI_SCR_SCBR_MASK              GENMASK(15, 8)
+#define QSPI_SCR_SCBR(n)                (((n) << 8) & QSPI_SCR_SCBR_MASK)
+#define QSPI_SCR_DLYBS_MASK             GENMASK(23, 16)
+#define QSPI_SCR_DLYBS(n)               (((n) << 16) & QSPI_SCR_DLYBS_MASK)
+
+/* Bitfields in QSPI_ICR (Instruction Code Register) */
+#define QSPI_ICR_INST_MASK              GENMASK(7, 0)
+#define QSPI_ICR_INST(inst)             (((inst) << 0) & QSPI_ICR_INST_MASK)
+#define QSPI_ICR_OPT_MASK               GENMASK(23, 16)
+#define QSPI_ICR_OPT(opt)               (((opt) << 16) & QSPI_ICR_OPT_MASK)
+
+/* Bitfields in QSPI_IFR (Instruction Frame Register) */
+#define QSPI_IFR_WIDTH_MASK             GENMASK(2, 0)
+#define QSPI_IFR_WIDTH_SINGLE_BIT_SPI   (0 << 0)
+#define QSPI_IFR_WIDTH_DUAL_OUTPUT      (1 << 0)
+#define QSPI_IFR_WIDTH_QUAD_OUTPUT      (2 << 0)
+#define QSPI_IFR_WIDTH_DUAL_IO          (3 << 0)
+#define QSPI_IFR_WIDTH_QUAD_IO          (4 << 0)
+#define QSPI_IFR_WIDTH_DUAL_CMD         (5 << 0)
+#define QSPI_IFR_WIDTH_QUAD_CMD         (6 << 0)
+#define QSPI_IFR_INSTEN                 BIT(4)
+#define QSPI_IFR_ADDREN                 BIT(5)
+#define QSPI_IFR_OPTEN                  BIT(6)
+#define QSPI_IFR_DATAEN                 BIT(7)
+#define QSPI_IFR_OPTL_MASK              GENMASK(9, 8)
+#define QSPI_IFR_OPTL_1BIT              (0 << 8)
+#define QSPI_IFR_OPTL_2BIT              (1 << 8)
+#define QSPI_IFR_OPTL_4BIT              (2 << 8)
+#define QSPI_IFR_OPTL_8BIT              (3 << 8)
+#define QSPI_IFR_ADDRL                  BIT(10)
+#define QSPI_IFR_TFRTYP_MASK            GENMASK(13, 12)
+#define QSPI_IFR_TFRTYP_TRSFR_READ      (0 << 12)
+#define QSPI_IFR_TFRTYP_TRSFR_READ_MEM  (1 << 12)
+#define QSPI_IFR_TFRTYP_TRSFR_WRITE     (2 << 12)
+#define QSPI_IFR_TFRTYP_TRSFR_WRITE_MEM (3 << 13)
+#define QSPI_IFR_CRM                    BIT(14)
+#define QSPI_IFR_NBDUM_MASK             GENMASK(20, 16)
+#define QSPI_IFR_NBDUM(n)               (((n) << 16) & QSPI_IFR_NBDUM_MASK)
+
+/* Bitfields in QSPI_SMR (Scrambling Mode Register) */
+#define QSPI_SMR_SCREN                  BIT(0)
+#define QSPI_SMR_RVDIS                  BIT(1)
+
+/* Bitfields in QSPI_WPMR (Write Protection Mode Register) */
+#define QSPI_WPMR_WPEN                  BIT(0)
+#define QSPI_WPMR_WPKEY_MASK            GENMASK(31, 8)
+#define QSPI_WPMR_WPKEY(wpkey)          (((wpkey) << 8) & QSPI_WPMR_WPKEY_MASK)
+
+/* Bitfields in QSPI_WPSR (Write Protection Status Register) */
+#define QSPI_WPSR_WPVS                  BIT(0)
+#define QSPI_WPSR_WPVSRC_MASK           GENMASK(15, 8)
+#define QSPI_WPSR_WPVSRC(src)           (((src) << 8) & QSPI_WPSR_WPVSRC)
+
+
+struct atmel_qspi {
+        void __iomem            *regs;
+        void __iomem            *mem;
+        struct clk              *clk;
+        struct platform_device  *pdev;
+        u32                     pending;
+        struct completion       cmd_completion;
+};
+
+struct qspi_mode {
+        u8 cmd_buswidth;
+        u8 addr_buswidth;
+        u8 data_buswidth;
+        u32 config;
+};
+
+static const struct qspi_mode sama5d2_qspi_modes[] = {
+        { 1, 1, 1, QSPI_IFR_WIDTH_SINGLE_BIT_SPI },
+        { 1, 1, 2, QSPI_IFR_WIDTH_DUAL_OUTPUT },
+        { 1, 1, 4, QSPI_IFR_WIDTH_QUAD_OUTPUT },
+        { 1, 2, 2, QSPI_IFR_WIDTH_DUAL_IO },
+        { 1, 4, 4, QSPI_IFR_WIDTH_QUAD_IO },
+        { 2, 2, 2, QSPI_IFR_WIDTH_DUAL_CMD },
+        { 4, 4, 4, QSPI_IFR_WIDTH_QUAD_CMD },
+};
+
+/* Register access functions */
+static inline u32 qspi_readl(struct atmel_qspi *aq, u32 reg)
+{
+        return readl_relaxed(aq->regs + reg);
+}
+
+static inline void qspi_writel(struct atmel_qspi *aq, u32 reg, u32 value)
+{
+        writel_relaxed(value, aq->regs + reg);
+}
+
+static inline bool is_compatible(const struct spi_mem_op *op,
+                                 const struct qspi_mode *mode)
+{
+        if (op->cmd.buswidth != mode->cmd_buswidth)
+                return false;
+
+        if (op->addr.nbytes && op->addr.buswidth != mode->addr_buswidth)
+                return false;
+
+        if (op->data.nbytes && op->data.buswidth != mode->data_buswidth)
+                return false;
+
+        return true;
+}
+
+static int find_mode(const struct spi_mem_op *op)
+{
+        u32 i;
+
+        for (i = 0; i < ARRAY_SIZE(sama5d2_qspi_modes); i++)
+                if (is_compatible(op, &sama5d2_qspi_modes[i]))
+                        return i;
+
+        return -1;
+}
+
+static bool atmel_qspi_supports_op(struct spi_mem *mem,
+                                   const struct spi_mem_op *op)
+{
+        if (find_mode(op) < 0)
+                return false;
+
+        /* special case not supported by hardware */
+        if (op->addr.nbytes == 2 && op->cmd.buswidth != op->addr.buswidth &&
+                op->dummy.nbytes == 0)
+                return false;
+
+        return true;
+}
+
+static int atmel_qspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
+{
+        struct atmel_qspi *aq = spi_controller_get_devdata(mem->spi->master);
+        int mode;
+        u32 dummy_cycles = 0;
+        u32 iar, icr, ifr, sr;
+        int err = 0;
+
+        iar = 0;
+        icr = QSPI_ICR_INST(op->cmd.opcode);
+        ifr = QSPI_IFR_INSTEN;
+
+        qspi_writel(aq, QSPI_MR, QSPI_MR_SMM);
+
+        mode = find_mode(op);
+        if (mode < 0)
+                return -ENOTSUPP;
+
+        ifr |= sama5d2_qspi_modes[mode].config;
+
+        if (op->dummy.buswidth && op->dummy.nbytes)
+                dummy_cycles = op->dummy.nbytes * 8 / op->dummy.buswidth;
+
+        if (op->addr.buswidth) {
+                switch (op->addr.nbytes) {
+                case 0:
+                        break;
+                case 1:
+                        ifr |= QSPI_IFR_OPTEN | QSPI_IFR_OPTL_8BIT;
+                        icr |= QSPI_ICR_OPT(op->addr.val & 0xff);
+                        break;
+                case 2:
+                        if (dummy_cycles < 8 / op->addr.buswidth) {
+                                ifr &= ~QSPI_IFR_INSTEN;
+                                ifr |= QSPI_IFR_ADDREN;
+                                iar = (op->cmd.opcode << 16) |
+                                        (op->addr.val & 0xffff);
+                        } else {
+                                ifr |= QSPI_IFR_ADDREN;
+                                iar = (op->addr.val << 8) & 0xffffff;
+                                dummy_cycles -= 8 / op->addr.buswidth;
+                        }
+                        break;
+                case 3:
+                        ifr |= QSPI_IFR_ADDREN;
+                        iar = op->addr.val & 0xffffff;
+                        break;
+                case 4:
+                        ifr |= QSPI_IFR_ADDREN | QSPI_IFR_ADDRL;
+                        iar = op->addr.val & 0x7ffffff;
+                        break;
+                default:
+                        return -ENOTSUPP;
+                }
+        }
+
+        /* Set number of dummy cycles */
+        if (dummy_cycles)
+                ifr |= QSPI_IFR_NBDUM(dummy_cycles);
+
+        /* Set data enable */
+        if (op->data.nbytes)
+                ifr |= QSPI_IFR_DATAEN;
+
+        if (op->data.dir == SPI_MEM_DATA_IN && op->data.nbytes)
+                ifr |= QSPI_IFR_TFRTYP_TRSFR_READ;
+        else
+                ifr |= QSPI_IFR_TFRTYP_TRSFR_WRITE;
+
+        /* Clear pending interrupts */
+        (void)qspi_readl(aq, QSPI_SR);
+
+        /* Set QSPI Instruction Frame registers */
+        qspi_writel(aq, QSPI_IAR, iar);
+        qspi_writel(aq, QSPI_ICR, icr);
+        qspi_writel(aq, QSPI_IFR, ifr);
+
+        /* Skip to the final steps if there is no data */
+        if (op->data.nbytes) {
+                /* Dummy read of QSPI_IFR to synchronize APB and AHB accesses */
+                (void)qspi_readl(aq, QSPI_IFR);
+
+                /* Send/Receive data */
+                if (op->data.dir == SPI_MEM_DATA_IN)
+                        _memcpy_fromio(op->data.buf.in,
+                                aq->mem + iar, op->data.nbytes);
+                else
+                        _memcpy_toio(aq->mem + iar,
+                                op->data.buf.out, op->data.nbytes);
+
+                /* Release the chip-select */
+                qspi_writel(aq, QSPI_CR, QSPI_CR_LASTXFER);
+        }
+
+        /* Poll INSTRuction End status */
+        sr = qspi_readl(aq, QSPI_SR);
+        if ((sr & QSPI_SR_CMD_COMPLETED) == QSPI_SR_CMD_COMPLETED)
+                return err;
+
+        /* Wait for INSTRuction End interrupt */
+        reinit_completion(&aq->cmd_completion);
+        aq->pending = sr & QSPI_SR_CMD_COMPLETED;
+        qspi_writel(aq, QSPI_IER, QSPI_SR_CMD_COMPLETED);
+        if (!wait_for_completion_timeout(&aq->cmd_completion,
+                                         msecs_to_jiffies(1000)))
+                err = -ETIMEDOUT;
+        qspi_writel(aq, QSPI_IDR, QSPI_SR_CMD_COMPLETED);
+
+        return err;
+}
+
+const char *atmel_qspi_get_name(struct spi_mem *spimem)
+{
+        return dev_name(spimem->spi->dev.parent);
+}
+
+static const struct spi_controller_mem_ops atmel_qspi_mem_ops = {
+        .supports_op = atmel_qspi_supports_op,
+        .exec_op = atmel_qspi_exec_op,
+        .get_name = atmel_qspi_get_name
+};
+
+static int atmel_qspi_setup(struct spi_device *spi)
+{
+        struct spi_controller *ctrl = spi->master;
+        struct atmel_qspi *aq = spi_controller_get_devdata(ctrl);
+        unsigned long src_rate;
+        u32 scr, scbr;
+
+        if (ctrl->busy)
+                return -EBUSY;
+
+        if (!spi->max_speed_hz)
+                return -EINVAL;
+
+        src_rate = clk_get_rate(aq->clk);
+        if (!src_rate)
+                return -EINVAL;
+
+        /* Compute the QSPI baudrate */
+        scbr = DIV_ROUND_UP(src_rate, spi->max_speed_hz);
+        if (scbr > 0)
+                scbr--;
+
+        scr = QSPI_SCR_SCBR(scbr);
+        qspi_writel(aq, QSPI_SCR, scr);
+
+        return 0;
+}
+
+static int atmel_qspi_init(struct atmel_qspi *aq)
+{
+        /* Reset the QSPI controller */
+        qspi_writel(aq, QSPI_CR, QSPI_CR_SWRST);
+
+        /* Enable the QSPI controller */
+        qspi_writel(aq, QSPI_CR, QSPI_CR_QSPIEN);
+
+        return 0;
+}
+
+static irqreturn_t atmel_qspi_interrupt(int irq, void *dev_id)
+{
+        struct atmel_qspi *aq = (struct atmel_qspi *)dev_id;
+        u32 status, mask, pending;
+
+        status = qspi_readl(aq, QSPI_SR);
+        mask = qspi_readl(aq, QSPI_IMR);
+        pending = status & mask;
+
+        if (!pending)
+                return IRQ_NONE;
+
+        aq->pending |= pending;
+        if ((aq->pending & QSPI_SR_CMD_COMPLETED) == QSPI_SR_CMD_COMPLETED)
+                complete(&aq->cmd_completion);
+
+        return IRQ_HANDLED;
+}
+
+static int atmel_qspi_probe(struct platform_device *pdev)
+{
+        struct spi_controller *ctrl;
+        struct atmel_qspi *aq;
+        struct resource *res;
+        int irq, err = 0;
+
+        ctrl = spi_alloc_master(&pdev->dev, sizeof(*aq));
+        if (!ctrl)
+                return -ENOMEM;
+
+        ctrl->mode_bits = SPI_RX_DUAL | SPI_RX_QUAD | SPI_TX_DUAL | SPI_TX_QUAD;
+        ctrl->setup = atmel_qspi_setup;
+        ctrl->bus_num = -1;
+        ctrl->mem_ops = &atmel_qspi_mem_ops;
+        ctrl->num_chipselect = 1;
+        ctrl->dev.of_node = pdev->dev.of_node;
+        platform_set_drvdata(pdev, ctrl);
+
+        aq = spi_controller_get_devdata(ctrl);
+
+        init_completion(&aq->cmd_completion);
+        aq->pdev = pdev;
+
+        /* Map the registers */
+        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "qspi_base");
+        aq->regs = devm_ioremap_resource(&pdev->dev, res);
+        if (IS_ERR(aq->regs)) {
+                dev_err(&pdev->dev, "missing registers\n");
+                err = PTR_ERR(aq->regs);
+                goto exit;
+        }
+
+        /* Map the AHB memory */
+        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "qspi_mmap");
+        aq->mem = devm_ioremap_resource(&pdev->dev, res);
+        if (IS_ERR(aq->mem)) {
+                dev_err(&pdev->dev, "missing AHB memory\n");
+                err = PTR_ERR(aq->mem);
+                goto exit;
+        }
+
+        /* Get the peripheral clock */
+        aq->clk = devm_clk_get(&pdev->dev, NULL);
+        if (IS_ERR(aq->clk)) {
+                dev_err(&pdev->dev, "missing peripheral clock\n");
+                err = PTR_ERR(aq->clk);
+                goto exit;
+        }
+
+        /* Enable the peripheral clock */
+        err = clk_prepare_enable(aq->clk);
+        if (err) {
+                dev_err(&pdev->dev, "failed to enable the peripheral clock\n");
+                goto exit;
+        }
+
+        /* Request the IRQ */
+        irq = platform_get_irq(pdev, 0);
+        if (irq < 0) {
+                dev_err(&pdev->dev, "missing IRQ\n");
+                err = irq;
+                goto disable_clk;
+        }
+        err = devm_request_irq(&pdev->dev, irq, atmel_qspi_interrupt,
+                               0, dev_name(&pdev->dev), aq);
+        if (err)
+                goto disable_clk;
+
+        err = atmel_qspi_init(aq);
+        if (err)
+                goto disable_clk;
+
+        err = spi_register_controller(ctrl);
+        if (err)
+                goto disable_clk;
+
+        return 0;
+
+disable_clk:
+        clk_disable_unprepare(aq->clk);
+exit:
+        spi_controller_put(ctrl);
+
+        return err;
+}
+
+static int atmel_qspi_remove(struct platform_device *pdev)
+{
+        struct spi_controller *ctrl = platform_get_drvdata(pdev);
+        struct atmel_qspi *aq = spi_controller_get_devdata(ctrl);
+
+        spi_unregister_controller(ctrl);
+        qspi_writel(aq, QSPI_CR, QSPI_CR_QSPIDIS);
+        clk_disable_unprepare(aq->clk);
+        return 0;
+}
+
+static int __maybe_unused atmel_qspi_suspend(struct device *dev)
+{
+        struct atmel_qspi *aq = dev_get_drvdata(dev);
+
+        clk_disable_unprepare(aq->clk);
+
+        return 0;
+}
+
+static int __maybe_unused atmel_qspi_resume(struct device *dev)
+{
+        struct atmel_qspi *aq = dev_get_drvdata(dev);
+
+        clk_prepare_enable(aq->clk);
+
+        return atmel_qspi_init(aq);
+}
+
+static SIMPLE_DEV_PM_OPS(atmel_qspi_pm_ops, atmel_qspi_suspend,
+                         atmel_qspi_resume);
+
+static const struct of_device_id atmel_qspi_dt_ids[] = {
+        { .compatible = "atmel,sama5d2-qspi" },
+        { /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, atmel_qspi_dt_ids);
+
+static struct platform_driver atmel_qspi_driver = {
+        .driver = {
+                .name   = "atmel_qspi",
+                .of_match_table = atmel_qspi_dt_ids,
+                .pm     = &atmel_qspi_pm_ops,
+        },
+        .probe          = atmel_qspi_probe,
+        .remove         = atmel_qspi_remove,
+};
+module_platform_driver(atmel_qspi_driver);
+
+MODULE_AUTHOR("Cyrille Pitchen <cyrille.pitchen@atmel.com>");
+MODULE_AUTHOR("Piotr Bugalski <bugalski.piotr@gmail.com");
+MODULE_DESCRIPTION("Atmel QSPI Controller driver");
+MODULE_LICENSE("GPL v2");