fpga: lattice machxo2: Add Lattice MachXO2 support

This patch adds support to the FPGA manager for programming
MachXO2 device’s internal flash memory, via slave SPI.

Signed-off-by: Paolo Pisati <p.pisati@gmail.com>
[atull@kernel.org: use existing FPGA mgr API]
Signed-off-by: Alan Tull <atull@kernel.org>
Signed-off-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 403 insertions, 0 deletions

diff --git a/drivers/fpga/machxo2-spi.c b/drivers/fpga/machxo2-spi.c
new file mode 100644
index 000000000000..8e95ec9c5c9a
--- /dev/null
+++ b/drivers/fpga/machxo2-spi.c
@@ -0,0 +1,403 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Lattice MachXO2 Slave SPI Driver
+ *
+ * Manage Lattice FPGA firmware that is loaded over SPI using
+ * the slave serial configuration interface.
+ *
+ * Copyright (C) 2018 Paolo Pisati <p.pisati@gmail.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/fpga/fpga-mgr.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/spi/spi.h>
+
+/* MachXO2 Programming Guide - sysCONFIG Programming Commands */
+#define IDCODE_PUB              {0xe0, 0x00, 0x00, 0x00}
+#define ISC_ENABLE              {0xc6, 0x08, 0x00, 0x00}
+#define ISC_ERASE               {0x0e, 0x04, 0x00, 0x00}
+#define ISC_PROGRAMDONE         {0x5e, 0x00, 0x00, 0x00}
+#define LSC_INITADDRESS         {0x46, 0x00, 0x00, 0x00}
+#define LSC_PROGINCRNV          {0x70, 0x00, 0x00, 0x01}
+#define LSC_READ_STATUS         {0x3c, 0x00, 0x00, 0x00}
+#define LSC_REFRESH             {0x79, 0x00, 0x00, 0x00}
+
+/*
+ * Max CCLK in Slave SPI mode according to 'MachXO2 Family Data
+ * Sheet' sysCONFIG Port Timing Specifications (3-36)
+ */
+#define MACHXO2_MAX_SPEED               66000000
+
+#define MACHXO2_LOW_DELAY_USEC          5
+#define MACHXO2_HIGH_DELAY_USEC         200
+#define MACHXO2_REFRESH_USEC            4800
+#define MACHXO2_MAX_BUSY_LOOP           128
+#define MACHXO2_MAX_REFRESH_LOOP        16
+
+#define MACHXO2_PAGE_SIZE               16
+#define MACHXO2_BUF_SIZE                (MACHXO2_PAGE_SIZE + 4)
+
+/* Status register bits, errors and error mask */
+#define BUSY    12
+#define DONE    8
+#define DVER    27
+#define ENAB    9
+#define ERRBITS 23
+#define ERRMASK 7
+#define FAIL    13
+
+#define ENOERR  0 /* no error */
+#define EID     1
+#define ECMD    2
+#define ECRC    3
+#define EPREAM  4 /* preamble error */
+#define EABRT   5 /* abort error */
+#define EOVERFL 6 /* overflow error */
+#define ESDMEOF 7 /* SDM EOF */
+
+static inline u8 get_err(unsigned long *status)
+{
+        return (*status >> ERRBITS) & ERRMASK;
+}
+
+static int get_status(struct spi_device *spi, unsigned long *status)
+{
+        struct spi_message msg;
+        struct spi_transfer rx, tx;
+        static const u8 cmd[] = LSC_READ_STATUS;
+        int ret;
+
+        memset(&rx, 0, sizeof(rx));
+        memset(&tx, 0, sizeof(tx));
+        tx.tx_buf = cmd;
+        tx.len = sizeof(cmd);
+        rx.rx_buf = status;
+        rx.len = 4;
+        spi_message_init(&msg);
+        spi_message_add_tail(&tx, &msg);
+        spi_message_add_tail(&rx, &msg);
+        ret = spi_sync(spi, &msg);
+        if (ret)
+                return ret;
+
+        *status = be32_to_cpu(*status);
+
+        return 0;
+}
+
+#ifdef DEBUG
+static const char *get_err_string(u8 err)
+{
+        switch (err) {
+        case ENOERR:    return "No Error";
+        case EID:       return "ID ERR";
+        case ECMD:      return "CMD ERR";
+        case ECRC:      return "CRC ERR";
+        case EPREAM:    return "Preamble ERR";
+        case EABRT:     return "Abort ERR";
+        case EOVERFL:   return "Overflow ERR";
+        case ESDMEOF:   return "SDM EOF";
+        }
+
+        return "Default switch case";
+}
+#endif
+
+static void dump_status_reg(unsigned long *status)
+{
+#ifdef DEBUG
+        pr_debug("machxo2 status: 0x%08lX - done=%d, cfgena=%d, busy=%d, fail=%d, devver=%d, err=%s\n",
+                 *status, test_bit(DONE, status), test_bit(ENAB, status),
+                 test_bit(BUSY, status), test_bit(FAIL, status),
+                 test_bit(DVER, status), get_err_string(get_err(status)));
+#endif
+}
+
+static int wait_until_not_busy(struct spi_device *spi)
+{
+        unsigned long status;
+        int ret, loop = 0;
+
+        do {
+                ret = get_status(spi, &status);
+                if (ret)
+                        return ret;
+                if (++loop >= MACHXO2_MAX_BUSY_LOOP)
+                        return -EBUSY;
+        } while (test_bit(BUSY, &status));
+
+        return 0;
+}
+
+static int machxo2_cleanup(struct fpga_manager *mgr)
+{
+        struct spi_device *spi = mgr->priv;
+        struct spi_message msg;
+        struct spi_transfer tx[2];
+        static const u8 erase[] = ISC_ERASE;
+        static const u8 refresh[] = LSC_REFRESH;
+        int ret;
+
+        memset(tx, 0, sizeof(tx));
+        spi_message_init(&msg);
+        tx[0].tx_buf = &erase;
+        tx[0].len = sizeof(erase);
+        spi_message_add_tail(&tx[0], &msg);
+        ret = spi_sync(spi, &msg);
+        if (ret)
+                goto fail;
+
+        ret = wait_until_not_busy(spi);
+        if (ret)
+                goto fail;
+
+        spi_message_init(&msg);
+        tx[1].tx_buf = &refresh;
+        tx[1].len = sizeof(refresh);
+        tx[1].delay_usecs = MACHXO2_REFRESH_USEC;
+        spi_message_add_tail(&tx[1], &msg);
+        ret = spi_sync(spi, &msg);
+        if (ret)
+                goto fail;
+
+        return 0;
+fail:
+        dev_err(&mgr->dev, "Cleanup failed\n");
+
+        return ret;
+}
+
+static enum fpga_mgr_states machxo2_spi_state(struct fpga_manager *mgr)
+{
+        struct spi_device *spi = mgr->priv;
+        unsigned long status;
+
+        get_status(spi, &status);
+        if (!test_bit(BUSY, &status) && test_bit(DONE, &status) &&
+            get_err(&status) == ENOERR)
+                return FPGA_MGR_STATE_OPERATING;
+
+        return FPGA_MGR_STATE_UNKNOWN;
+}
+
+static int machxo2_write_init(struct fpga_manager *mgr,
+                              struct fpga_image_info *info,
+                              const char *buf, size_t count)
+{
+        struct spi_device *spi = mgr->priv;
+        struct spi_message msg;
+        struct spi_transfer tx[3];
+        static const u8 enable[] = ISC_ENABLE;
+        static const u8 erase[] = ISC_ERASE;
+        static const u8 initaddr[] = LSC_INITADDRESS;
+        unsigned long status;
+        int ret;
+
+        if ((info->flags & FPGA_MGR_PARTIAL_RECONFIG)) {
+                dev_err(&mgr->dev,
+                        "Partial reconfiguration is not supported\n");
+                return -ENOTSUPP;
+        }
+
+        get_status(spi, &status);
+        dump_status_reg(&status);
+        memset(tx, 0, sizeof(tx));
+        spi_message_init(&msg);
+        tx[0].tx_buf = &enable;
+        tx[0].len = sizeof(enable);
+        tx[0].delay_usecs = MACHXO2_LOW_DELAY_USEC;
+        spi_message_add_tail(&tx[0], &msg);
+
+        tx[1].tx_buf = &erase;
+        tx[1].len = sizeof(erase);
+        spi_message_add_tail(&tx[1], &msg);
+        ret = spi_sync(spi, &msg);
+        if (ret)
+                goto fail;
+
+        ret = wait_until_not_busy(spi);
+        if (ret)
+                goto fail;
+
+        get_status(spi, &status);
+        if (test_bit(FAIL, &status))
+                goto fail;
+        dump_status_reg(&status);
+
+        spi_message_init(&msg);
+        tx[2].tx_buf = &initaddr;
+        tx[2].len = sizeof(initaddr);
+        spi_message_add_tail(&tx[2], &msg);
+        ret = spi_sync(spi, &msg);
+        if (ret)
+                goto fail;
+
+        get_status(spi, &status);
+        dump_status_reg(&status);
+
+        return 0;
+fail:
+        dev_err(&mgr->dev, "Error during FPGA init.\n");
+
+        return ret;
+}
+
+static int machxo2_write(struct fpga_manager *mgr, const char *buf,
+                         size_t count)
+{
+        struct spi_device *spi = mgr->priv;
+        struct spi_message msg;
+        struct spi_transfer tx;
+        static const u8 progincr[] = LSC_PROGINCRNV;
+        u8 payload[MACHXO2_BUF_SIZE];
+        unsigned long status;
+        int i, ret;
+
+        if (count % MACHXO2_PAGE_SIZE != 0) {
+                dev_err(&mgr->dev, "Malformed payload.\n");
+                return -EINVAL;
+        }
+        get_status(spi, &status);
+        dump_status_reg(&status);
+        memcpy(payload, &progincr, sizeof(progincr));
+        for (i = 0; i < count; i += MACHXO2_PAGE_SIZE) {
+                memcpy(&payload[sizeof(progincr)], &buf[i], MACHXO2_PAGE_SIZE);
+                memset(&tx, 0, sizeof(tx));
+                spi_message_init(&msg);
+                tx.tx_buf = payload;
+                tx.len = MACHXO2_BUF_SIZE;
+                tx.delay_usecs = MACHXO2_HIGH_DELAY_USEC;
+                spi_message_add_tail(&tx, &msg);
+                ret = spi_sync(spi, &msg);
+                if (ret) {
+                        dev_err(&mgr->dev, "Error loading the bitstream.\n");
+                        return ret;
+                }
+        }
+        get_status(spi, &status);
+        dump_status_reg(&status);
+
+        return 0;
+}
+
+static int machxo2_write_complete(struct fpga_manager *mgr,
+                                  struct fpga_image_info *info)
+{
+        struct spi_device *spi = mgr->priv;
+        struct spi_message msg;
+        struct spi_transfer tx[2];
+        static const u8 progdone[] = ISC_PROGRAMDONE;
+        static const u8 refresh[] = LSC_REFRESH;
+        unsigned long status;
+        int ret, refreshloop = 0;
+
+        memset(tx, 0, sizeof(tx));
+        spi_message_init(&msg);
+        tx[0].tx_buf = &progdone;
+        tx[0].len = sizeof(progdone);
+        spi_message_add_tail(&tx[0], &msg);
+        ret = spi_sync(spi, &msg);
+        if (ret)
+                goto fail;
+        ret = wait_until_not_busy(spi);
+        if (ret)
+                goto fail;
+
+        get_status(spi, &status);
+        dump_status_reg(&status);
+        if (!test_bit(DONE, &status)) {
+                machxo2_cleanup(mgr);
+                goto fail;
+        }
+
+        do {
+                spi_message_init(&msg);
+                tx[1].tx_buf = &refresh;
+                tx[1].len = sizeof(refresh);
+                tx[1].delay_usecs = MACHXO2_REFRESH_USEC;
+                spi_message_add_tail(&tx[1], &msg);
+                ret = spi_sync(spi, &msg);
+                if (ret)
+                        goto fail;
+
+                /* check refresh status */
+                get_status(spi, &status);
+                dump_status_reg(&status);
+                if (!test_bit(BUSY, &status) && test_bit(DONE, &status) &&
+                    get_err(&status) == ENOERR)
+                        break;
+                if (++refreshloop == MACHXO2_MAX_REFRESH_LOOP) {
+                        machxo2_cleanup(mgr);
+                        goto fail;
+                }
+        } while (1);
+
+        get_status(spi, &status);
+        dump_status_reg(&status);
+
+        return 0;
+fail:
+        dev_err(&mgr->dev, "Refresh failed.\n");
+
+        return ret;
+}
+
+static const struct fpga_manager_ops machxo2_ops = {
+        .state = machxo2_spi_state,
+        .write_init = machxo2_write_init,
+        .write = machxo2_write,
+        .write_complete = machxo2_write_complete,
+};
+
+static int machxo2_spi_probe(struct spi_device *spi)
+{
+        struct device *dev = &spi->dev;
+
+        if (spi->max_speed_hz > MACHXO2_MAX_SPEED) {
+                dev_err(dev, "Speed is too high\n");
+                return -EINVAL;
+        }
+
+        return fpga_mgr_register(dev, "Lattice MachXO2 SPI FPGA Manager",
+                                 &machxo2_ops, spi);
+}
+
+static int machxo2_spi_remove(struct spi_device *spi)
+{
+        struct device *dev = &spi->dev;
+
+        fpga_mgr_unregister(dev);
+
+        return 0;
+}
+
+static const struct of_device_id of_match[] = {
+        { .compatible = "lattice,machxo2-slave-spi", },
+        {}
+};
+MODULE_DEVICE_TABLE(of, of_match);
+
+static const struct spi_device_id lattice_ids[] = {
+        { "machxo2-slave-spi", 0 },
+        { },
+};
+MODULE_DEVICE_TABLE(spi, lattice_ids);
+
+static struct spi_driver machxo2_spi_driver = {
+        .driver = {
+                .name = "machxo2-slave-spi",
+                .of_match_table = of_match_ptr(of_match),
+        },
+        .probe = machxo2_spi_probe,
+        .remove = machxo2_spi_remove,
+        .id_table = lattice_ids,
+};
+
+module_spi_driver(machxo2_spi_driver)
+
+MODULE_AUTHOR("Paolo Pisati <p.pisati@gmail.com>");
+MODULE_DESCRIPTION("Load Lattice FPGA firmware over SPI");
+MODULE_LICENSE("GPL v2");