[PATCH] powerpc: Add support to access the flash on SLOF based systems
Adrian Reber
adrian at lisas.de
Sun Jan 11 02:31:22 EST 2009
This adds support for a simple character device to access the
flash for SLOF based systems like the PowerStation, QS2x and
PXCAB. In the SLOF git there is a user space program with
which the content of the flash for SLOF based systems can
be displayed and modified. This can be used to add a Linux
image to the flash and then directly boot the kernel from the
flash.
Signed-off-by: Adrian Reber <adrian at lisas.de>
---
This is based on the mmio NVRAM driver. I am not sure how useful this
is for anybody else but I am posting it anyway, hoping to get some
feedback. Also hoping it can be included at one point.
arch/powerpc/platforms/Kconfig | 8 ++
arch/powerpc/sysdev/Makefile | 2 +
arch/powerpc/sysdev/slof_flash.c | 174 ++++++++++++++++++++++++++++++++++++++
include/linux/miscdevice.h | 1 +
4 files changed, 185 insertions(+), 0 deletions(-)
create mode 100644 arch/powerpc/sysdev/slof_flash.c
diff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kconfig
index 47fe2be..7f436e0 100644
--- a/arch/powerpc/platforms/Kconfig
+++ b/arch/powerpc/platforms/Kconfig
@@ -301,6 +301,14 @@ config OF_RTC
Uses information from the OF or flattened device tree to instatiate
platform devices for direct mapped RTC chips like the DS1742 or DS1743.
+config SLOF_FLASH
+ bool "SLOF flash device"
+ depends on PPC_MAPLE || PPC_IBM_CELL_BLADE
+ default y
+ help
+ Provide a read-only device to read out the flash
+ for SLOF based systems.
+
source "arch/powerpc/sysdev/bestcomm/Kconfig"
config MPC8xxx_GPIO
diff --git a/arch/powerpc/sysdev/Makefile b/arch/powerpc/sysdev/Makefile
index b33b28a..298485d 100644
--- a/arch/powerpc/sysdev/Makefile
+++ b/arch/powerpc/sysdev/Makefile
@@ -50,3 +50,5 @@ obj-$(CONFIG_UCODE_PATCH) += micropatch.o
ifeq ($(CONFIG_SUSPEND),y)
obj-$(CONFIG_6xx) += 6xx-suspend.o
endif
+
+obj-$(CONFIG_SLOF_FLASH) += slof_flash.o
diff --git a/arch/powerpc/sysdev/slof_flash.c b/arch/powerpc/sysdev/slof_flash.c
new file mode 100644
index 0000000..bc94d48
--- /dev/null
+++ b/arch/powerpc/sysdev/slof_flash.c
@@ -0,0 +1,174 @@
+/*
+ * SLOF flash access
+ *
+ * (C) Copyright MATRIX VISION GmbH 2009
+ *
+ * Authors : Adrian Reber <adrian at lisas.de>
+ *
+ * Based on mmio NVRAM driver
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+
+#include <linux/miscdevice.h>
+#include <asm/uaccess.h>
+#include <asm/prom.h>
+#include <asm/machdep.h>
+
+static void __iomem *slof_flash_start;
+static long slof_flash_len;
+static DEFINE_SPINLOCK(slof_flash_lock);
+
+static loff_t slof_flash_llseek(struct file *file, loff_t offset, int origin)
+{
+ switch (origin) {
+ case 1:
+ offset += file->f_pos;
+ break;
+ case 2:
+ offset += slof_flash_len;
+ break;
+ }
+ if (offset < 0)
+ return -EINVAL;
+ file->f_pos = offset;
+ return file->f_pos;
+}
+
+
+static ssize_t slof_flash_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ unsigned long flags;
+ char *tmp;
+ int rc;
+
+ if (*ppos >= slof_flash_len)
+ return 0;
+ if (*ppos + count > slof_flash_len)
+ count = slof_flash_len - *ppos;
+
+ count = min(count, PAGE_SIZE);
+ tmp = kzalloc(count, GFP_KERNEL);
+
+ if (!tmp)
+ return -ENOMEM;
+
+ spin_lock_irqsave(&slof_flash_lock, flags);
+
+ memcpy_fromio(tmp, slof_flash_start + *ppos, count);
+
+ spin_unlock_irqrestore(&slof_flash_lock, flags);
+
+ rc = count;
+ if (copy_to_user(buf, tmp, count)) {
+ rc = -EFAULT;
+ goto out;
+ }
+
+ *ppos += count;
+out:
+ kfree(tmp);
+ return rc;
+}
+
+const struct file_operations slof_flash_fops = {
+ .owner = THIS_MODULE,
+ .llseek = slof_flash_llseek,
+ .read = slof_flash_read,
+};
+
+static struct miscdevice slof_flash_dev = {
+ SLOF_FLASH_MINOR,
+ "slof_flash",
+ &slof_flash_fops
+};
+
+
+static int __init slof_flash_init(void)
+{
+ struct device_node *slof_flash;
+ struct device_node *compatible;
+ struct resource r;
+ int rc;
+ unsigned long slof_flash_addr;
+ /* SLOF is known to run on systems with following values
+ * for the compatible property: */
+ char *compstrs[] = {"IBM,Bimini", "IBM,JS21", "IBM,JS20", "IBM,CBEA" };
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(compstrs); i++) {
+ compatible = of_find_compatible_node(NULL, NULL, compstrs[i]);
+
+ if (compatible)
+ break;
+ }
+
+ /* not a system with a SLOF flash */
+ if (!compatible)
+ return -ENODEV;
+
+ of_node_put(compatible);
+
+ slof_flash = of_find_node_by_type(NULL, "flash");
+ if (!slof_flash) {
+ printk(KERN_WARNING "SLOF FLASH: "
+ "no flash node found in device-tree\n");
+ return -ENODEV;
+ }
+ rc = of_address_to_resource(slof_flash, 0, &r);
+ if (rc) {
+ printk(KERN_WARNING "SLOF FLASH: "
+ "failed to get address (err %d)\n", rc);
+ goto out;
+ }
+
+ slof_flash_addr = r.start;
+ slof_flash_len = r.end - r.start + 1;
+
+ if ((slof_flash_len <= 0) || (!slof_flash_addr)) {
+ printk(KERN_WARNING "SLOF FLASH: address or length is 0\n");
+ rc = -EIO;
+ goto out;
+ }
+
+ slof_flash_start = ioremap(slof_flash_addr, slof_flash_len);
+ if (!slof_flash_start) {
+ printk(KERN_WARNING "SLOF FLASH: failed to ioremap\n");
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ printk(KERN_INFO "SLOF FLASH: %luk at 0x%lx mapped to %p\n",
+ slof_flash_len >> 10, slof_flash_addr, slof_flash_start);
+
+ rc = misc_register(&slof_flash_dev);
+ if (rc != 0)
+ printk(KERN_ERR "SLOF FLASH: failed to register device\n");
+
+out:
+ of_node_put(slof_flash);
+ return rc;
+}
+
+void __exit slof_flash_cleanup(void)
+{
+ misc_deregister(&slof_flash_dev);
+}
+
+module_init(slof_flash_init);
+module_exit(slof_flash_cleanup);
+MODULE_LICENSE("GPL");
diff --git a/include/linux/miscdevice.h b/include/linux/miscdevice.h
index a820f81..0887042 100644
--- a/include/linux/miscdevice.h
+++ b/include/linux/miscdevice.h
@@ -19,6 +19,7 @@
#define SUN_OPENPROM_MINOR 139
#define DMAPI_MINOR 140 /* DMAPI */
#define NVRAM_MINOR 144
+#define SLOF_FLASH_MINOR 145
#define SGI_MMTIMER 153
#define STORE_QUEUE_MINOR 155
#define I2O_MINOR 166
--
1.6.0.6
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