[PATCH 3/3] FPGA: provide a handler to program ALTERA FPGAs
Juergen Beisert
jbe at pengutronix.de
Wed Nov 6 09:24:41 EST 2013
This handler uses a regular SPI master and a few GPIO to program an ALTERA FPGA
in serial mode.
Signed-off-by: Juergen Beisert <jbe at pengutronix.de>
---
drivers/Kconfig | 1 +
drivers/Makefile | 1 +
drivers/fpga/Kconfig | 10 ++
drivers/fpga/Makefile | 2 +
drivers/fpga/altera_serial.c | 278 +++++++++++++++++++++++++++++++++++++++++++
5 files changed, 292 insertions(+)
create mode 100644 drivers/fpga/Kconfig
create mode 100644 drivers/fpga/Makefile
create mode 100644 drivers/fpga/altera_serial.c
diff --git a/drivers/Kconfig b/drivers/Kconfig
index d34d2c7..ac3c699 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -25,5 +25,6 @@ source "drivers/gpio/Kconfig"
source "drivers/w1/Kconfig"
source "drivers/pinctrl/Kconfig"
source "drivers/bus/Kconfig"
+source "drivers/fpga/Kconfig"
endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index ba1dc6d..fa4aace 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -24,3 +24,4 @@ obj-$(CONFIG_OFTREE) += of/
obj-$(CONFIG_W1) += w1/
obj-y += pinctrl/
obj-y += bus/
+obj-y += fpga/
diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
new file mode 100644
index 0000000..204e852
--- /dev/null
+++ b/drivers/fpga/Kconfig
@@ -0,0 +1,10 @@
+menu "FPGA programming"
+
+config ALTERA_SERIAL
+ bool "Altera SPI programming"
+ depends on FPGAMANAGER && OFDEVICE
+ help
+ Programming an Altera FPGA via a few GPIOs for the control lines and
+ MOSI, MISO and clock from an SPI interface for the data lines
+
+endmenu
diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
new file mode 100644
index 0000000..3147634
--- /dev/null
+++ b/drivers/fpga/Makefile
@@ -0,0 +1,2 @@
+
+obj-$(CONFIG_ALTERA_SERIAL) += altera_serial.o
diff --git a/drivers/fpga/altera_serial.c b/drivers/fpga/altera_serial.c
new file mode 100644
index 0000000..cf05845
--- /dev/null
+++ b/drivers/fpga/altera_serial.c
@@ -0,0 +1,278 @@
+/*
+ * Copyright (c) 2013 Juergen Beisert <kernel at pengutronix.de>, Pengutronix
+ *
+ * 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.
+ */
+#include <common.h>
+#include <init.h>
+#include <driver.h>
+#include <fpgamgr.h>
+#include <of_gpio.h>
+#include <xfuncs.h>
+#include <malloc.h>
+#include <gpio.h>
+#include <clock.h>
+#include <spi/spi.h>
+
+/*
+ * Physical requirements:
+ * - three free GPIOs for the signals nCONFIG, CONFIGURE_DONE, nSTATUS
+ * - 32 bit per word, LSB first capable SPI master (MOSI + clock)
+ *
+ * Example how to configure this driver via device tree
+ *
+ * fpga at 0 {
+ * compatible = "altera_serial";
+ * nstat-gpio = <&gpio4 18 0>;
+ * confd-gpio = <&gpio4 19 0>;
+ * nconfig-gpio = <&gpio4 20 0>;
+ * spi-max-frequency = <10000000>;
+ * reg = <0>;
+ * };
+ */
+
+struct fpga_spi {
+ int nstat_gpio; /* input GPIO to read the status line */
+ int confd_gpio; /* input GPIO to read the config done line */
+ int nconfig_gpio; /* output GPIO to start the FPGA's config */
+ struct device_d *dev;
+ struct spi_device *spi;
+ bool padding_done;
+};
+
+static int altera_spi_open(struct fpga_handler *h)
+{
+ struct fpga_spi *this = (struct fpga_spi *)h->private_data;
+ struct device_d *dev = this->dev;
+ int ret;
+
+ dev_dbg(dev, "Initiating programming\n");
+
+ /* initiate an FPGA programming */
+ gpio_set_value(this->nconfig_gpio, 0);
+
+ /*
+ * after about 2 µs the FPGA must acknowledge with
+ * STATUS and CONFIG DONE lines at low level
+ */
+ ret = wait_on_timeout(2 * 1000,
+ (gpio_get_value(this->nstat_gpio) == 0) &&
+ (gpio_get_value(this->confd_gpio) == 0));
+
+ if (ret != 0) {
+ dev_err(dev, "FPGA does not acknowledge the programming initiation\n");
+ if (gpio_get_value(this->nstat_gpio))
+ dev_err(dev, "STATUS is still high!\n");
+ if (gpio_get_value(this->confd_gpio))
+ dev_err(dev, "CONFIG DONE is still high!\n");
+ return ret;
+ }
+
+ /* arm the FPGA to await its new firmware */
+ gpio_set_value(this->nconfig_gpio, 1);
+
+ /* once again, we might need padding the data */
+ this->padding_done = false;
+
+ /*
+ * after about 1506 µs the FPGA must acknowledge this step
+ * with the STATUS line at high level
+ */
+ ret = wait_on_timeout(1600 * 1000,
+ gpio_get_value(this->nstat_gpio) == 1);
+ if (ret != 0) {
+ dev_err(dev, "FPGA does not acknowledge the programming start\n");
+ return ret;
+ }
+
+ dev_dbg(dev, "Initiating passed\n");
+ /* at the end, wait at least 2 µs prior beginning writing data */
+ ndelay(2 * 1000);
+
+ return 0;
+}
+
+static int altera_spi_write(struct fpga_handler *h, const void *buf, size_t sz)
+{
+ struct fpga_spi *this = (struct fpga_spi *)h->private_data;
+ struct device_d *dev = this->dev;
+ struct spi_transfer t[2];
+ struct spi_message m;
+ u32 dummy;
+ int ret;
+
+ spi_message_init(&m);
+
+ if (sz < sizeof(u32)) {
+ /* simple padding */
+ dummy = 0;
+ memcpy(&dummy, buf, sz);
+ buf = &dummy;
+ sz = sizeof(u32);
+ this->padding_done = true;
+ }
+
+ t[0].tx_buf = buf;
+ t[0].rx_buf = NULL;
+ t[0].len = sz;
+ spi_message_add_tail(&t[0], &m);
+
+ if (sz & 0x3) { /* padding required? */
+ u32 *word_buf = (u32 *)buf;
+ dummy = 0;
+ memcpy(&dummy, &word_buf[sz >> 2], sz & 0x3);
+ t[0].len &= ~0x03;
+ t[1].tx_buf = &dummy;
+ t[1].rx_buf = NULL;
+ t[1].len = sizeof(u32);
+ spi_message_add_tail(&t[1], &m);
+ this->padding_done = true;
+ }
+
+ ret = spi_sync(this->spi, &m);
+ if (ret != 0)
+ dev_err(dev, "programming failure\n");
+
+ return ret;
+}
+
+static int altera_spi_close(struct fpga_handler *h)
+{
+ struct fpga_spi *this = (struct fpga_spi *)h->private_data;
+ struct device_d *dev = this->dev;
+ struct spi_transfer t;
+ struct spi_message m;
+ u32 dummy = 0;
+ int ret;
+
+ dev_dbg(dev, "Finalize programming\n");
+
+ if (this->padding_done == false) {
+ spi_message_init(&m);
+ t.tx_buf = &dummy;
+ t.rx_buf = NULL;
+ t.len = sizeof(dummy);
+ spi_message_add_tail(&t, &m);
+
+ ret = spi_sync(this->spi, &m);
+ if (ret != 0)
+ dev_err(dev, "programming failure\n");
+ }
+
+ /*
+ * when programming was successfully,
+ * both status lines should be at high level
+ */
+ ret = wait_on_timeout(10 * 1000,
+ (gpio_get_value(this->nstat_gpio) == 1) &&
+ (gpio_get_value(this->confd_gpio) == 1));
+ if (ret == 0) {
+ dev_dbg(dev, "Programming successfull\n");
+ return ret;
+ }
+
+ dev_err(dev, "Programming failed due to time out\n");
+ if (gpio_get_value(this->nstat_gpio) == 0)
+ dev_err(dev, "STATUS is still low!\n");
+ if (gpio_get_value(this->confd_gpio) == 0)
+ dev_err(dev, "CONFIG DONE is still low!\n");
+
+ return -EIO;
+}
+
+static int altera_spi_of(struct device_d *dev, struct fpga_spi *this)
+{
+ struct device_node *n = dev->device_node;
+
+ this->nstat_gpio = of_get_named_gpio(n, "nstat-gpio", 0);
+ if (this->nstat_gpio < 0) {
+ dev_err(dev, "Illegal value for the STATUS input GPIO\n");
+ return this->nstat_gpio;
+ }
+ this->confd_gpio = of_get_named_gpio(n, "confd-gpio", 0);
+ if (this->confd_gpio < 0) {
+ dev_err(dev, "Illegal value for the CONFIG DONE input GPIO\n");
+ return this->confd_gpio;
+ }
+ this->nconfig_gpio = of_get_named_gpio(n, "nconfig-gpio", 0);
+ if (this->nconfig_gpio < 0) {
+ dev_err(dev, "Illegal value for the CONFIGURE output GPIO\n");
+ return this->nconfig_gpio;
+ }
+
+ /* init to passive and sane values */
+ gpio_direction_output(this->nconfig_gpio, 1);
+ gpio_direction_input(this->nstat_gpio);
+ gpio_direction_input(this->confd_gpio);
+
+ return 0;
+}
+
+static void altera_spi_init_mode(struct spi_device *spi)
+{
+ spi->bits_per_word = 32;
+ /*
+ * CPHA = CPOL = 0
+ * the FPGA expects its firmware data with LSB first
+ */
+ spi->mode = SPI_MODE_0 | SPI_LSB_FIRST;
+}
+
+static int altera_spi_probe(struct device_d *dev)
+{
+ int rc;
+ struct fpga_spi *this;
+ struct fpga_handler *h;
+ const char *alias = of_alias_get(dev->device_node);
+
+ dev_dbg(dev, "Probing FPGA firmware programmer\n");
+ h = xzalloc(sizeof(struct fpga_spi) + sizeof(struct fpga_handler));
+ this = (struct fpga_spi *)&h[1];
+ h->private_data = this;
+
+ rc = altera_spi_of(dev, this);
+ if (rc != 0)
+ return rc;
+
+ if (alias)
+ h->name = xstrdup(alias);
+ else
+ h->name = "fpga";
+
+ h->open = altera_spi_open;
+ h->write = altera_spi_write;
+ h->close = altera_spi_close;
+
+ this->spi = (struct spi_device *)dev->type_data;
+ altera_spi_init_mode(this->spi);
+ this->dev = dev;
+
+ dev_dbg(dev, "Registering FPGA firmware programmer\n");
+ rc = fpgamgr_register_handler(h);
+ if (rc != 0) {
+ free(h);
+ return rc;
+ }
+
+ return 0;
+}
+
+static struct of_device_id altera_spi_id_table[] = {
+ {
+ .compatible = "altera_serial",
+ },
+};
+
+static struct driver_d altera_spi_driver = {
+ .name = "fpga_spi",
+ .of_compatible = DRV_OF_COMPAT(altera_spi_id_table),
+ .probe = altera_spi_probe,
+};
+device_spi_driver(altera_spi_driver);
--
1.8.4.rc3
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