4 files changed, 535 insertions, 0 deletions

diff --git a/arch/tile/include/hv/drv_srom_intf.h b/arch/tile/include/hv/drv_srom_intf.h
new file mode 100644
index 000000000000..6395faa6d9e6
--- /dev/null
+++ b/arch/tile/include/hv/drv_srom_intf.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright 2011 Tilera Corporation. All Rights Reserved.
+ *
+ *   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, version 2.
+ *
+ *   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, GOOD TITLE or
+ *   NON INFRINGEMENT.  See the GNU General Public License for
+ *   more details.
+ */
+
+/**
+ * @file drv_srom_intf.h
+ * Interface definitions for the SPI Flash ROM driver.
+ */
+
+#ifndef _SYS_HV_INCLUDE_DRV_SROM_INTF_H
+#define _SYS_HV_INCLUDE_DRV_SROM_INTF_H
+
+/** Read this offset to get the total device size. */
+#define SROM_TOTAL_SIZE_OFF   0xF0000000
+
+/** Read this offset to get the device sector size. */
+#define SROM_SECTOR_SIZE_OFF  0xF0000004
+
+/** Read this offset to get the device page size. */
+#define SROM_PAGE_SIZE_OFF    0xF0000008
+
+/** Write this offset to flush any pending writes. */
+#define SROM_FLUSH_OFF        0xF1000000
+
+/** Write this offset, plus the byte offset of the start of a sector, to
+ *  erase a sector.  Any write data is ignored, but there must be at least
+ *  one byte of write data.  Only applies when the driver is in MTD mode.
+ */
+#define SROM_ERASE_OFF        0xF2000000
+
+#endif /* _SYS_HV_INCLUDE_DRV_SROM_INTF_H */
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 49502bc5360a..423fd56bf612 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -616,5 +616,16 @@ config MSM_SMD_PKT
           Enables userspace clients to read and write to some packet SMD
           ports via device interface for MSM chipset.
 
+config TILE_SROM
+        bool "Character-device access via hypervisor to the Tilera SPI ROM"
+        depends on TILE
+        default y
+        ---help---
+          This device provides character-level read-write access
+          to the SROM, typically via the "0", "1", and "2" devices
+          in /dev/srom/.  The Tilera hypervisor makes the flash
+          device appear much like a simple EEPROM, and knows
+          how to partition a single ROM for multiple purposes.
+
 endmenu
 
diff --git a/drivers/char/Makefile b/drivers/char/Makefile
index 7a00672bd85d..32762ba769c2 100644
--- a/drivers/char/Makefile
+++ b/drivers/char/Makefile
@@ -63,3 +63,5 @@ obj-$(CONFIG_RAMOOPS)		+= ramoops.o
 
 obj-$(CONFIG_JS_RTC)            += js-rtc.o
 js-rtc-y = rtc.o
+
+obj-$(CONFIG_TILE_SROM)         += tile-srom.o
diff --git a/drivers/char/tile-srom.c b/drivers/char/tile-srom.c
new file mode 100644
index 000000000000..cf3ee008dca2
--- /dev/null
+++ b/drivers/char/tile-srom.c
@@ -0,0 +1,481 @@
+/*
+ * Copyright 2011 Tilera Corporation. All Rights Reserved.
+ *
+ *   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, version 2.
+ *
+ *   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, GOOD TITLE or
+ *   NON INFRINGEMENT.  See the GNU General Public License for
+ *   more details.
+ *
+ * SPI Flash ROM driver
+ *
+ * This source code is derived from code provided in "Linux Device
+ * Drivers, Third Edition", by Jonathan Corbet, Alessandro Rubini, and
+ * Greg Kroah-Hartman, published by O'Reilly Media, Inc.
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/init.h>
+#include <linux/kernel.h>       /* printk() */
+#include <linux/slab.h>         /* kmalloc() */
+#include <linux/fs.h>           /* everything... */
+#include <linux/errno.h>        /* error codes */
+#include <linux/types.h>        /* size_t */
+#include <linux/proc_fs.h>
+#include <linux/fcntl.h>        /* O_ACCMODE */
+#include <linux/aio.h>
+#include <linux/pagemap.h>
+#include <linux/hugetlb.h>
+#include <linux/uaccess.h>
+#include <linux/platform_device.h>
+#include <hv/hypervisor.h>
+#include <linux/ioctl.h>
+#include <linux/cdev.h>
+#include <linux/delay.h>
+#include <hv/drv_srom_intf.h>
+
+/*
+ * Size of our hypervisor I/O requests.  We break up large transfers
+ * so that we don't spend large uninterrupted spans of time in the
+ * hypervisor.  Erasing an SROM sector takes a significant fraction of
+ * a second, so if we allowed the user to, say, do one I/O to write the
+ * entire ROM, we'd get soft lockup timeouts, or worse.
+ */
+#define SROM_CHUNK_SIZE ((size_t)4096)
+
+/*
+ * When hypervisor is busy (e.g. erasing), poll the status periodically.
+ */
+
+/*
+ * Interval to poll the state in msec
+ */
+#define SROM_WAIT_TRY_INTERVAL 20
+
+/*
+ * Maximum times to poll the state
+ */
+#define SROM_MAX_WAIT_TRY_TIMES 1000
+
+struct srom_dev {
+        int hv_devhdl;                  /* Handle for hypervisor device */
+        u32 total_size;                 /* Size of this device */
+        u32 sector_size;                /* Size of a sector */
+        u32 page_size;                  /* Size of a page */
+        struct mutex lock;              /* Allow only one accessor at a time */
+};
+
+static int srom_major;                  /* Dynamic major by default */
+module_param(srom_major, int, 0);
+MODULE_AUTHOR("Tilera Corporation");
+MODULE_LICENSE("GPL");
+
+static int srom_devs;                   /* Number of SROM partitions */
+static struct cdev srom_cdev;
+static struct class *srom_class;
+static struct srom_dev *srom_devices;
+
+/*
+ * Handle calling the hypervisor and managing EAGAIN/EBUSY.
+ */
+
+static ssize_t _srom_read(int hv_devhdl, void *buf,
+                          loff_t off, size_t count)
+{
+        int retval, retries = SROM_MAX_WAIT_TRY_TIMES;
+        for (;;) {
+                retval = hv_dev_pread(hv_devhdl, 0, (HV_VirtAddr)buf,
+                                      count, off);
+                if (retval >= 0)
+                        return retval;
+                if (retval == HV_EAGAIN)
+                        continue;
+                if (retval == HV_EBUSY && --retries > 0) {
+                        msleep(SROM_WAIT_TRY_INTERVAL);
+                        continue;
+                }
+                pr_err("_srom_read: error %d\n", retval);
+                return -EIO;
+        }
+}
+
+static ssize_t _srom_write(int hv_devhdl, const void *buf,
+                           loff_t off, size_t count)
+{
+        int retval, retries = SROM_MAX_WAIT_TRY_TIMES;
+        for (;;) {
+                retval = hv_dev_pwrite(hv_devhdl, 0, (HV_VirtAddr)buf,
+                                       count, off);
+                if (retval >= 0)
+                        return retval;
+                if (retval == HV_EAGAIN)
+                        continue;
+                if (retval == HV_EBUSY && --retries > 0) {
+                        msleep(SROM_WAIT_TRY_INTERVAL);
+                        continue;
+                }
+                pr_err("_srom_write: error %d\n", retval);
+                return -EIO;
+        }
+}