| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <200903061414.01500.david-b@pacbell.net>
Date: Fri, 6 Mar 2009 14:14:01 -0800
From: David Brownell <david-b@...bell.net>
To: Kevin Hilman <khilman@...prootsystems.com>
Cc: linux-kernel@...r.kernel.org
Subject: Re: [PATCH] eeprom: add kernel interface for reading/writing persistent memory
From: David Brownell <dbrownell@...rs.sourceforge.net>
Implement the new memory_accessor interfaces for SPI EEPROMs:
- Define new setup() hook to export the accessor
- Implement accessor methods
Moves some error checking out of the sysfs interface code
into the layer below it, which is now shared by both sysfs
and memory access code.
Signed-off-by: David Brownell <dbrownell@...rs.sourceforge.net>
---
Can't have this only for I2C ... SPI may need it too. :)
drivers/misc/eeprom/at25.c | 58 ++++++++++++++++++++++++++++++++-----------
include/linux/spi/eeprom.h | 6 ++++
2 files changed, 50 insertions(+), 14 deletions(-)
--- a/drivers/misc/eeprom/at25.c
+++ b/drivers/misc/eeprom/at25.c
@@ -30,6 +30,7 @@
struct at25_data {
struct spi_device *spi;
+ struct memory_accessor mem;
struct mutex lock;
struct spi_eeprom chip;
struct bin_attribute bin;
@@ -75,6 +76,13 @@ at25_ee_read(
struct spi_transfer t[2];
struct spi_message m;
+ if (unlikely(offset >= at25->bin.size))
+ return 0;
+ if ((offset + count) > at25->bin.size)
+ count = at25->bin.size - offset;
+ if (unlikely(!count))
+ return count;
+
cp = command;
*cp++ = AT25_READ;
@@ -127,13 +135,6 @@ at25_bin_read(struct kobject *kobj, stru
dev = container_of(kobj, struct device, kobj);
at25 = dev_get_drvdata(dev);
- if (unlikely(off >= at25->bin.size))
- return 0;
- if ((off + count) > at25->bin.size)
- count = at25->bin.size - off;
- if (unlikely(!count))
- return count;
-
return at25_ee_read(at25, buf, off, count);
}
@@ -146,6 +147,13 @@ at25_ee_write(struct at25_data *at25, ch
unsigned buf_size;
u8 *bounce;
+ if (unlikely(off >= at25->bin.size))
+ return -EFBIG;
+ if ((off + count) > at25->bin.size)
+ count = at25->bin.size - off;
+ if (unlikely(!count))
+ return count;
+
/* Temp buffer starts with command and address */
buf_size = at25->chip.page_size;
if (buf_size > io_limit)
@@ -253,18 +261,31 @@ at25_bin_write(struct kobject *kobj, str
dev = container_of(kobj, struct device, kobj);
at25 = dev_get_drvdata(dev);
- if (unlikely(off >= at25->bin.size))
- return -EFBIG;
- if ((off + count) > at25->bin.size)
- count = at25->bin.size - off;
- if (unlikely(!count))
- return count;
-
return at25_ee_write(at25, buf, off, count);
}
/*-------------------------------------------------------------------------*/
+/* Let in-kernel code access the eeprom data. */
+
+static ssize_t at25_mem_read(struct memory_accessor *mem, char *buf,
+ off_t offset, size_t count)
+{
+ struct at25_data *at25 = container_of(mem, struct at25_data, mem);
+
+ return at25_ee_read(at25, buf, offset, count);
+}
+
+static ssize_t at25_mem_write(struct memory_accessor *mem, char *buf,
+ off_t offset, size_t count)
+{
+ struct at25_data *at25 = container_of(mem, struct at25_data, mem);
+
+ return at25_ee_write(at25, buf, offset, count);
+}
+
+/*-------------------------------------------------------------------------*/
+
static int at25_probe(struct spi_device *spi)
{
struct at25_data *at25 = NULL;
@@ -317,6 +338,10 @@ static int at25_probe(struct spi_device
at25->addrlen = addrlen;
/* Export the EEPROM bytes through sysfs, since that's convenient.
+ * And maybe to other kernel code; it might hold a board's Ethernet
+ * address, or board-specific calibration data generated on the
+ * manufacturing floor.
+ *
* Default to root-only access to the data; EEPROMs often hold data
* that's sensitive for read and/or write, like ethernet addresses,
* security codes, board-specific manufacturing calibrations, etc.
@@ -324,17 +349,22 @@ static int at25_probe(struct spi_device
at25->bin.attr.name = "eeprom";
at25->bin.attr.mode = S_IRUSR;
at25->bin.read = at25_bin_read;
+ at25->mem.read = at25_mem_read;
at25->bin.size = at25->chip.byte_len;
if (!(chip->flags & EE_READONLY)) {
at25->bin.write = at25_bin_write;
at25->bin.attr.mode |= S_IWUSR;
+ at25->mem.write = at25_mem_write;
}
err = sysfs_create_bin_file(&spi->dev.kobj, &at25->bin);
if (err)
goto fail;
+ if (chip->setup)
+ chip->setup(&at25->mem, chip->context);
+
dev_info(&spi->dev, "%Zd %s %s eeprom%s, pagesize %u\n",
(at25->bin.size < 1024)
? at25->bin.size
--- a/include/linux/spi/eeprom.h
+++ b/include/linux/spi/eeprom.h
@@ -1,6 +1,8 @@
#ifndef __LINUX_SPI_EEPROM_H
#define __LINUX_SPI_EEPROM_H
+#include <linux/memory.h>
+
/*
* Put one of these structures in platform_data for SPI EEPROMS handled
* by the "at25" driver. On SPI, most EEPROMS understand the same core
@@ -17,6 +19,10 @@ struct spi_eeprom {
#define EE_ADDR2 0x0002 /* 16 bit addrs */
#define EE_ADDR3 0x0004 /* 24 bit addrs */
#define EE_READONLY 0x0008 /* disallow writes */
+
+ /* for exporting this chip's data to other kernel code */
+ void (*setup)(struct memory_accessor *mem, void *context);
+ void *context;
};
#endif /* __LINUX_SPI_EEPROM_H */
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists