sfc: Expose flash region storing boot code as MTD

The boot code that appears as a PCI expansion ROM on the SFC4000 is
stored in flash.  Expose this as a standard MTD device to allow for
in-place upgrades.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 268 insertions, 0 deletions

diff --git a/drivers/net/sfc/mtd.c b/drivers/net/sfc/mtd.c
new file mode 100644
index 0000000..a1e6c28
--- /dev/null
+++ b/drivers/net/sfc/mtd.c
@@ -0,0 +1,268 @@
+/****************************************************************************
+ * Driver for Solarflare Solarstorm network controllers and boards
+ * Copyright 2005-2006 Fen Systems Ltd.
+ * Copyright 2006-2008 Solarflare Communications Inc.
+ *
+ * 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, incorporated herein by reference.
+ */
+
+#include <linux/module.h>
+#include <linux/mtd/mtd.h>
+#include <linux/delay.h>
+
+#define EFX_DRIVER_NAME "sfc_mtd"
+#include "net_driver.h"
+#include "spi.h"
+
+#define EFX_SPI_VERIFY_BUF_LEN 16
+
+struct efx_mtd {
+	const struct efx_spi_device *spi;
+	struct mtd_info mtd;
+	char name[IFNAMSIZ + 20];
+};
+
+/* SPI utilities */
+
+static int efx_spi_slow_wait(struct efx_mtd *efx_mtd, bool uninterruptible)
+{
+	const struct efx_spi_device *spi = efx_mtd->spi;
+	struct efx_nic *efx = spi->efx;
+	u8 status;
+	int rc, i;
+
+	/* Wait up to 4s for flash/EEPROM to finish a slow operation. */
+	for (i = 0; i < 40; i++) {
+		__set_current_state(uninterruptible ?
+				    TASK_UNINTERRUPTIBLE : TASK_INTERRUPTIBLE);
+		schedule_timeout(HZ / 10);
+		rc = falcon_spi_cmd(spi, SPI_RDSR, -1, NULL,
+				    &status, sizeof(status));
+		if (rc)
+			return rc;
+		if (!(status & SPI_STATUS_NRDY))
+			return 0;
+		if (signal_pending(current))
+			return -EINTR;
+	}
+	EFX_ERR(efx, "timed out waiting for %s\n", efx_mtd->name);
+	return -ETIMEDOUT;
+}
+
+static int efx_spi_unlock(const struct efx_spi_device *spi)
+{
+	const u8 unlock_mask = (SPI_STATUS_BP2 | SPI_STATUS_BP1 |
+				SPI_STATUS_BP0);
+	u8 status;
+	int rc;
+
+	rc = falcon_spi_cmd(spi, SPI_RDSR, -1, NULL, &status, sizeof(status));
+	if (rc)
+		return rc;
+
+	if (!(status & unlock_mask))
+		return 0; /* already unlocked */
+
+	rc = falcon_spi_cmd(spi, SPI_WREN, -1, NULL, NULL, 0);
+	if (rc)
+		return rc;
+	rc = falcon_spi_cmd(spi, SPI_SST_EWSR, -1, NULL, NULL, 0);
+	if (rc)
+		return rc;
+
+	status &= ~unlock_mask;
+	rc = falcon_spi_cmd(spi, SPI_WRSR, -1, &status, NULL, sizeof(status));
+	if (rc)
+		return rc;
+	rc = falcon_spi_fast_wait(spi);
+	if (rc)
+		return rc;
+
+	return 0;
+}
+
+static int efx_spi_erase(struct efx_mtd *efx_mtd, loff_t start, size_t len)
+{
+	const struct efx_spi_device *spi = efx_mtd->spi;
+	unsigned pos, block_len;
+	u8 empty[EFX_SPI_VERIFY_BUF_LEN];
+	u8 buffer[EFX_SPI_VERIFY_BUF_LEN];
+	int rc;
+
+	if (len != spi->erase_size)
+		return -EINVAL;
+
+	if (spi->erase_command == 0)
+		return -EOPNOTSUPP;
+
+	rc = efx_spi_unlock(spi);
+	if (rc)
+		return rc;
+	rc = falcon_spi_cmd(spi, SPI_WREN, -1, NULL, NULL, 0);
+	if (rc)
+		return rc;
+	rc = falcon_spi_cmd(spi, spi->erase_command, start, NULL, NULL, 0);
+	if (rc)
+		return rc;
+	rc = efx_spi_slow_wait(efx_mtd, false);
+
+	/* Verify the entire region has been wiped */
+	memset(empty, 0xff, sizeof(empty));
+	for (pos = 0; pos < len; pos += block_len) {
+		block_len = min(len - pos, sizeof(buffer));
+		rc = falcon_spi_read(spi, start + pos, block_len, NULL, buffer);
+		if (rc)
+			return rc;
+		if (memcmp(empty, buffer, block_len))
+			return -EIO;
+
+		/* Avoid locking up the system */
+		cond_resched();
+		if (signal_pending(current))
+			return -EINTR;
+	}
+
+	return rc;
+}
+
+/* MTD interface */
+
+static int efx_mtd_read(struct mtd_info *mtd, loff_t start, size_t len,
+			size_t *retlen, u8 *buffer)
+{
+	struct efx_mtd *efx_mtd = mtd->priv;
+	const struct efx_spi_device *spi = efx_mtd->spi;
+	struct efx_nic *efx = spi->efx;
+	int rc;
+
+	rc = mutex_lock_interruptible(&efx->spi_lock);
+	if (rc)
+		return rc;
+	rc = falcon_spi_read(spi, FALCON_FLASH_BOOTCODE_START + start,
+			     len, retlen, buffer);
+	mutex_unlock(&efx->spi_lock);
+	return rc;
+}
+
+static int efx_mtd_erase(struct mtd_info *mtd, struct erase_info *erase)
+{
+	struct efx_mtd *efx_mtd = mtd->priv;
+	struct efx_nic *efx = efx_mtd->spi->efx;
+	int rc;
+
+	rc = mutex_lock_interruptible(&efx->spi_lock);
+	if (rc)
+		return rc;
+	rc = efx_spi_erase(efx_mtd, FALCON_FLASH_BOOTCODE_START + erase->addr,
+			   erase->len);
+	mutex_unlock(&efx->spi_lock);
+
+	if (rc == 0) {
+		erase->state = MTD_ERASE_DONE;
+	} else {
+		erase->state = MTD_ERASE_FAILED;
+		erase->fail_addr = 0xffffffff;
+	}
+	mtd_erase_callback(erase);
+	return rc;
+}
+
+static int efx_mtd_write(struct mtd_info *mtd, loff_t start,
+			 size_t len, size_t *retlen, const u8 *buffer)
+{
+	struct efx_mtd *efx_mtd = mtd->priv;
+	const struct efx_spi_device *spi = efx_mtd->spi;
+	struct efx_nic *efx = spi->efx;
+	int rc;
+
+	rc = mutex_lock_interruptible(&efx->spi_lock);
+	if (rc)
+		return rc;
+	rc = falcon_spi_write(spi, FALCON_FLASH_BOOTCODE_START + start,
+			      len, retlen, buffer);
+	mutex_unlock(&efx->spi_lock);
+	return rc;
+}
+
+static void efx_mtd_sync(struct mtd_info *mtd)
+{
+	struct efx_mtd *efx_mtd = mtd->priv;
+	struct efx_nic *efx = efx_mtd->spi->efx;
+	int rc;
+
+	mutex_lock(&efx->spi_lock);
+	rc = efx_spi_slow_wait(efx_mtd, true);
+	mutex_unlock(&efx->spi_lock);
+
+	if (rc)
+		EFX_ERR(efx, "%s sync failed (%d)\n", efx_mtd->name, rc);
+	return;
+}
+
+void efx_mtd_remove(struct efx_nic *efx)
+{
+	if (efx->spi_flash && efx->spi_flash->mtd) {
+		struct efx_mtd *efx_mtd = efx->spi_flash->mtd;
+		int rc;
+
+		for (;;) {
+			rc = del_mtd_device(&efx_mtd->mtd);
+			if (rc != -EBUSY)
+				break;
+			ssleep(1);
+		}
+		WARN_ON(rc);
+		kfree(efx_mtd);
+	}
+}
+
+void efx_mtd_rename(struct efx_nic *efx)
+{
+	if (efx->spi_flash && efx->spi_flash->mtd) {
+		struct efx_mtd *efx_mtd = efx->spi_flash->mtd;
+		snprintf(efx_mtd->name, sizeof(efx_mtd->name),
+			 "%s sfc_flash_bootrom", efx->name);
+	}
+}
+
+int efx_mtd_probe(struct efx_nic *efx)
+{
+	struct efx_spi_device *spi = efx->spi_flash;
+	struct efx_mtd *efx_mtd;
+
+	if (!spi || spi->size <= FALCON_FLASH_BOOTCODE_START)
+		return -ENODEV;
+
+	efx_mtd = kzalloc(sizeof(*efx_mtd), GFP_KERNEL);
+	if (!efx_mtd)
+		return -ENOMEM;
+
+	efx_mtd->spi = spi;
+	spi->mtd = efx_mtd;
+
+	efx_mtd->mtd.type = MTD_NORFLASH;
+	efx_mtd->mtd.flags = MTD_CAP_NORFLASH;
+	efx_mtd->mtd.size = spi->size - FALCON_FLASH_BOOTCODE_START;
+	efx_mtd->mtd.erasesize = spi->erase_size;
+	efx_mtd->mtd.writesize = 1;
+	efx_mtd_rename(efx);
+
+	efx_mtd->mtd.owner = THIS_MODULE;
+	efx_mtd->mtd.priv = efx_mtd;
+	efx_mtd->mtd.name = efx_mtd->name;
+	efx_mtd->mtd.erase = efx_mtd_erase;
+	efx_mtd->mtd.read = efx_mtd_read;
+	efx_mtd->mtd.write = efx_mtd_write;
+	efx_mtd->mtd.sync = efx_mtd_sync;
+
+	if (add_mtd_device(&efx_mtd->mtd)) {
+		kfree(efx_mtd);
+		spi->mtd = NULL;
+		/* add_mtd_device() returns 1 if the MTD table is full */
+		return -ENOMEM;
+	}
+
+	return 0;
+}