[PATCH/RFC] Create mtdram device at runtime.

[PATCH/RFC] Create mtdram device at runtime.

[johan.adolfsson]

The following patch moves most of the stuff out from the init_mtdram() 
function into a non static mtdram_init_device() function that can be 
called from other places in the kernel, 
e.g. from a mapping routine to map in a cramfs image in RAM using 
the mtd layer:-)
To prevent the device from being created by init_mtdram using the
configured values, CONFIG_MTDRAM_TOTAL_SIZE should be set to 0
(The help should be updated as well)

A new file: include/linux/mtd/mtdram.h is created as well.

Still some things missing regarding cleanup on exit for modules.

This is a first shot at it and it seems to work for us, but the
API should perhaps be tweaked a little bit more, i.e. providing the
flags and erase size as well.

Does it make enough sense to go into the official version 
(after some tweaking)?

/Johan


diff -u -p -r1.1.1.3 mtdram.c
--- linux/drivers/mtd/devices/mtdram.c 23 Apr 2002 13:18:59 -0000 1.1.1.3
+++ linux/drivers/mtd/devices/mtdram.c 30 Apr 2002 09:28:23 -0000
@@ -118,7 +118,7 @@ static void __exit cleanup_mtdram(void)
   }
 }

-int __init init_mtdram(void)
+int mtdram_init_device(void *mapped_address, unsigned long size, char
*name)
 {
    // Allocate some memory
    mtd_info = (struct mtd_info *)kmalloc(sizeof(struct mtd_info),
GFP_KERNEL);
@@ -128,26 +128,14 @@ int __init init_mtdram(void)
    memset(mtd_info, 0, sizeof(*mtd_info));

    // Setup the MTD structure
-   mtd_info->name = "mtdram test device";
+   mtd_info->name = name;
    mtd_info->type = MTD_RAM;
    mtd_info->flags = MTD_CAP_RAM;
-   mtd_info->size = MTDRAM_TOTAL_SIZE;
+   mtd_info->size = size;
    mtd_info->erasesize = MTDRAM_ERASE_SIZE;
-#if CONFIG_MTDRAM_ABS_POS > 0
-   mtd_info->priv = ioremap(CONFIG_MTDRAM_ABS_POS, MTDRAM_TOTAL_SIZE);
-#else
-   mtd_info->priv = vmalloc(MTDRAM_TOTAL_SIZE);
-#endif
-
-   if (!mtd_info->priv) {
-     DEBUG(MTD_DEBUG_LEVEL1, "Failed to vmalloc(/ioremap) memory region of
size %ld (ABS_POS:%ld)\n", (long)MTDRAM_TOTAL_SIZE,
(long)CONFIG_MTDRAM_ABS_POS);
-     kfree(mtd_info);
-     mtd_info = NULL;
-     return -ENOMEM;
-   }
-   memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
+   mtd_info->priv = mapped_address;

-   mtd_info->module = THIS_MODULE;
+   mtd_info->module = THIS_MODULE;
    mtd_info->erase = ram_erase;
    mtd_info->point = ram_point;
    mtd_info->unpoint = ram_unpoint;
@@ -155,11 +143,6 @@ int __init init_mtdram(void)
    mtd_info->write = ram_write;

    if (add_mtd_device(mtd_info)) {
-#if CONFIG_MTDRAM_ABS_POS > 0
-     iounmap(mtd_info->priv);
-#else
-     vfree(mtd_info->priv);
-#endif
      kfree(mtd_info);
      mtd_info = NULL;
      return -EIO;
@@ -168,10 +151,42 @@ int __init init_mtdram(void)
    return 0;
 }

+int __init init_mtdram(void)
+{
+  void *addr;
+  int err = 0;
+#if CONFIG_MTDRAM_TOTAL_SIZE > 0
+#if CONFIG_MTDRAM_ABS_POS > 0
+   addr = ioremap(CONFIG_MTDRAM_ABS_POS, MTDRAM_TOTAL_SIZE);
+#else
+   addr = vmalloc(MTDRAM_TOTAL_SIZE);
+#endif
+   if (!addr) {
+     DEBUG(MTD_DEBUG_LEVEL1, "Failed to vmalloc(/ioremap) memory region of
size %ld (ABS_POS:%ld)\n", (long)MTDRAM_TOTAL_SIZE,
(long)CONFIG_MTDRAM_ABS_POS);
+     kfree(mtd_info);
+     mtd_info = NULL;
+     return -ENOMEM;
+   }
+   err = mtdram_init_device(addr, MTDRAM_TOTAL_SIZE, "mtdram test device";
+   if (err)
+   {
+#if CONFIG_MTDRAM_ABS_POS > 0
+     iounmap(mtd_info->priv);
+#else
+     vfree(mtd_info->priv);
+#endif
+   }
+   memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
+#endif /* CONFIG_MTDRAM_TOTAL_SIZE > 0 */
+   return err;
+}
+
+
 module_init(init_mtdram);
 module_exit(cleanup_mtdram);

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
 MODULE_DESCRIPTION("Simulated MTD driver for testing");
+

--- /dev/null Sat Mar 24 05:37:44 2001
+++ linux/include/linux/mtd/mtdram.h Mon Apr 29 18:12:14 2002
@@ -0,0 +1,8 @@
+#ifndef __MTD_MTDRAM_H__
+#define __MTD_MTDRAM_H__
+
+#ifdef __KERNEL__
+int mtdram_init_device(void *mapped_address, unsigned long size, char
*name);
+
+#endif /* __KERNEL__ */
+#endif /* __MTD_MTDRAM_H__ */

Re: [PATCH/RFC] Create mtdram device at runtime.

[David Woodhouse]

johan.adolfsson@axis.com said:
>  Does it make enough sense to go into the official version  (after
> some tweaking)? 

Looks OK. Can you split the new init_mtdram() into two entirely separate 
functions; one for the CONFIG_MTDRAM_ABS_POS case, one for the vmalloc() 
case?

--
dwmw2

Re: [PATCH/RFC] Create mtdram device at runtime.

[johan.adolfsson]

> Looks OK. Can you split the new init_mtdram() into two entirely separate
> functions; one for the CONFIG_MTDRAM_ABS_POS case, one for the vmalloc()
> case?
Here it comes, not tested though...
Beleive I took care of the cleanup as well.

/Johan


diff -u -p -r1.1.1.3 mtdram.c
--- linux/drivers/mtd/devices/mtdram.c 23 Apr 2002 13:18:59 -0000 1.1.1.3
+++ linux/drivers/mtd/devices/mtdram.c 30 Apr 2002 10:24:15 -0000
@@ -108,17 +108,19 @@ static void __exit cleanup_mtdram(void)
 {
   if (mtd_info) {
     del_mtd_device(mtd_info);
+#if CONFIG_MTDRAM_TOTAL_SIZE > 0
     if (mtd_info->priv)
 #if CONFIG_MTDRAM_ABS_POS > 0
       iounmap(mtd_info->priv);
 #else
       vfree(mtd_info->priv);
 #endif
+#endif
     kfree(mtd_info);
   }
 }

-int __init init_mtdram(void)
+int mtdram_init_device(void *mapped_address, unsigned long size, char
*name)
 {
    // Allocate some memory
    mtd_info = (struct mtd_info *)kmalloc(sizeof(struct mtd_info),
GFP_KERNEL);
@@ -128,26 +130,14 @@ int __init init_mtdram(void)
    memset(mtd_info, 0, sizeof(*mtd_info));

    // Setup the MTD structure
-   mtd_info->name = "mtdram test device";
+   mtd_info->name = name;
    mtd_info->type = MTD_RAM;
    mtd_info->flags = MTD_CAP_RAM;
-   mtd_info->size = MTDRAM_TOTAL_SIZE;
+   mtd_info->size = size;
    mtd_info->erasesize = MTDRAM_ERASE_SIZE;
-#if CONFIG_MTDRAM_ABS_POS > 0
-   mtd_info->priv = ioremap(CONFIG_MTDRAM_ABS_POS, MTDRAM_TOTAL_SIZE);
-#else
-   mtd_info->priv = vmalloc(MTDRAM_TOTAL_SIZE);
-#endif
-
-   if (!mtd_info->priv) {
-     DEBUG(MTD_DEBUG_LEVEL1, "Failed to vmalloc(/ioremap) memory region of
size %ld (ABS_POS:%ld)\n", (long)MTDRAM_TOTAL_SIZE,
(long)CONFIG_MTDRAM_ABS_POS);
-     kfree(mtd_info);
-     mtd_info = NULL;
-     return -ENOMEM;
-   }
-   memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
+   mtd_info->priv = mapped_address;

-   mtd_info->module = THIS_MODULE;
+   mtd_info->module = THIS_MODULE;
    mtd_info->erase = ram_erase;
    mtd_info->point = ram_point;
    mtd_info->unpoint = ram_unpoint;
@@ -155,11 +145,6 @@ int __init init_mtdram(void)
    mtd_info->write = ram_write;

    if (add_mtd_device(mtd_info)) {
-#if CONFIG_MTDRAM_ABS_POS > 0
-     iounmap(mtd_info->priv);
-#else
-     vfree(mtd_info->priv);
-#endif
      kfree(mtd_info);
      mtd_info = NULL;
      return -EIO;
@@ -167,6 +152,64 @@ int __init init_mtdram(void)

    return 0;
 }
+
+#if CONFIG_MTDRAM_TOTAL_SIZE > 0
+#if CONFIG_MTDRAM_ABS_POS > 0
+int __init init_mtdram(void)
+{
+  void *addr;
+  int err = 0;
+  addr = ioremap(CONFIG_MTDRAM_ABS_POS, MTDRAM_TOTAL_SIZE);
+  if (!addr) {
+    DEBUG(MTD_DEBUG_LEVEL1,
+          "Failed to ioremap) memory region of size %ld at ABS_POS:%ld\n",
+          (long)MTDRAM_TOTAL_SIZE, (long)CONFIG_MTDRAM_ABS_POS);
+    kfree(mtd_info);
+    mtd_info = NULL;
+    return -ENOMEM;
+  }
+  err = mtdram_init_device(addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
+  if (err)
+  {
+    iounmap(mtd_info->priv);
+  }
+  memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
+  return err;
+}
+
+#else /* CONFIG_MTDRAM_ABS_POS > 0 */
+
+int __init init_mtdram(void)
+{
+  void *addr;
+  int err = 0;
+  addr = vmalloc(MTDRAM_TOTAL_SIZE);
+  if (!addr) {
+    DEBUG(MTD_DEBUG_LEVEL1,
+          "Failed to vmalloc memory region of size %ld\n",
+          (long)MTDRAM_TOTAL_SIZE);
+    kfree(mtd_info);
+    mtd_info = NULL;
+    return -ENOMEM;
+  }
+  err = mtdram_init_device(addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
+  if (err)
+  {
+    vfree(mtd_info->priv);
+  }
+  memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
+
+  return err;
+}
+#endif /* !(CONFIG_MTDRAM_ABS_POS > 0) */
+
+#else /* CONFIG_MTDRAM_TOTAL_SIZE > 0 */
+
+int __init init_mtdram(void)
+{
+  return 0;
+}
+#endif /* !(CONFIG_MTDRAM_TOTAL_SIZE > 0) */

 module_init(init_mtdram);
 module_exit(cleanup_mtdram);

Re: [PATCH/RFC] Create mtdram device at runtime.

[David Woodhouse]

johan.adolfsson@axis.com said:
> Here it comes, not tested though... Beleive I took care of the cleanup
> as well.

What about the case where mtdram_init_device() is called from elsewhere?
Perhaps we should register a cleanup function with as mtdram_init_device()
and call _that_ in the later cleanup?

--
dwmw2

Re: [PATCH/RFC] Create mtdram device at runtime.

[johan.adolfsson]

> johan.adolfsson@axis.com said:
> > Here it comes, not tested though... Beleive I took care of the cleanup
> > as well.
>
> What about the case where mtdram_init_device() is called from elsewhere?
> Perhaps we should register a cleanup function with as mtdram_init_device()
> and call _that_ in the later cleanup?
> --
> dwmw2

How about letting mtdram_init_device return an allocated mtd_info*
and the caller is responsible for cleaning it up?
The hardcoded init functions store the returned pointer in the
static mtd_info variable and do it's clean-up on exit.

/Johan

Re: [PATCH/RFC] Create mtdram device at runtime.

[David Woodhouse]

johan.adolfsson@axis.com said:
>  How about letting mtdram_init_device return an allocated mtd_info*
> and the caller is responsible for cleaning it up? The hardcoded init
> functions store the returned pointer in the static mtd_info variable
> and do it's clean-up on exit.

Seems reasonable.

--
dwmw2

Re: [PATCH/RFC] Create mtdram device at runtime.

[Johan Adolfsson]

This time I think I got it right...
The caller of mtdram_init_device() is responsible for allocating the
mtd_info struct and to provide the memoryarea.
The caller is also repsonsible for freeing and deleting the stuff
if needed.
cleanup_mtdram() handles that for the non dynamic case, but otherwise
it's up to the caller, no helper function is provided (nor needed really).

/Johan

---

diff -u -p -r1.1.1.3 mtdram.c
--- linux/drivers/mtd/devices/mtdram.c 23 Apr 2002 13:18:59 -0000 1.1.1.3
+++ linux/drivers/mtd/devices/mtdram.c 6 May 2002 08:31:52 -0000
@@ -108,65 +108,119 @@ static void __exit cleanup_mtdram(void)
 {
   if (mtd_info) {
     del_mtd_device(mtd_info);
+#if CONFIG_MTDRAM_TOTAL_SIZE > 0
     if (mtd_info->priv)
 #if CONFIG_MTDRAM_ABS_POS > 0
       iounmap(mtd_info->priv);
 #else
       vfree(mtd_info->priv);
 #endif
+#endif
     kfree(mtd_info);
   }
 }

+int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
+                       unsigned long size, char *name)
+{
+   memset(mtd, 0, sizeof(*mtd));
+
+   /* Setup the MTD structure */
+   mtd->name = name;
+   mtd->type = MTD_RAM;
+   mtd->flags = MTD_CAP_RAM;
+   mtd->size = size;
+   mtd->erasesize = MTDRAM_ERASE_SIZE;
+   mtd->priv = mapped_address;
+
+   mtd->module = THIS_MODULE;
+   mtd->erase = ram_erase;
+   mtd->point = ram_point;
+   mtd->unpoint = ram_unpoint;
+   mtd->read = ram_read;
+   mtd->write = ram_write;
+
+   if (add_mtd_device(mtd)) {
+     return -EIO;
+   }
+
+   return 0;
+}
+
+#if CONFIG_MTDRAM_TOTAL_SIZE > 0
+#if CONFIG_MTDRAM_ABS_POS > 0
 int __init init_mtdram(void)
 {
-   // Allocate some memory
-   mtd_info = (struct mtd_info *)kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
+  void *addr;
+  int err;
+  /* Allocate some memory */
+   mtd_info = (struct mtd_info *)kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
    if (!mtd_info)
-      return -ENOMEM;
+     return -ENOMEM;

-   memset(mtd_info, 0, sizeof(*mtd_info));
+  addr = ioremap(CONFIG_MTDRAM_ABS_POS, MTDRAM_TOTAL_SIZE);
+  if (!addr) {
+    DEBUG(MTD_DEBUG_LEVEL1,
+          "Failed to ioremap) memory region of size %ld at ABS_POS:%ld\n",
+          (long)MTDRAM_TOTAL_SIZE, (long)CONFIG_MTDRAM_ABS_POS);
+    kfree(mtd_info);
+    mtd_info = NULL;
+    return -ENOMEM;
+  }
+  err = mtdram_init_device(mtd_info, addr,
+                           MTDRAM_TOTAL_SIZE, "mtdram test device");
+  if (err)
+  {
+    iounmap(addr);
+    kfree(mtd_info);
+    mtd_info = NULL;
+    return err;
+  }
+  memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
+  return err;
+}

-   // Setup the MTD structure
-   mtd_info->name = "mtdram test device";
-   mtd_info->type = MTD_RAM;
-   mtd_info->flags = MTD_CAP_RAM;
-   mtd_info->size = MTDRAM_TOTAL_SIZE;
-   mtd_info->erasesize = MTDRAM_ERASE_SIZE;
-#if CONFIG_MTDRAM_ABS_POS > 0
-   mtd_info->priv = ioremap(CONFIG_MTDRAM_ABS_POS, MTDRAM_TOTAL_SIZE);
-#else
-   mtd_info->priv = vmalloc(MTDRAM_TOTAL_SIZE);
-#endif
+#else /* CONFIG_MTDRAM_ABS_POS > 0 */

-   if (!mtd_info->priv) {
-     DEBUG(MTD_DEBUG_LEVEL1, "Failed to vmalloc(/ioremap) memory region of size %ld (ABS_POS:%ld)\n",
(long)MTDRAM_TOTAL_SIZE, (long)CONFIG_MTDRAM_ABS_POS);
-     kfree(mtd_info);
-     mtd_info = NULL;
+int __init init_mtdram(void)
+{
+  void *addr;
+  int err;
+  /* Allocate some memory */
+   mtd_info = (struct mtd_info *)kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
+   if (!mtd_info)
      return -ENOMEM;
-   }
-   memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);

-   mtd_info->module = THIS_MODULE;
-   mtd_info->erase = ram_erase;
-   mtd_info->point = ram_point;
-   mtd_info->unpoint = ram_unpoint;
-   mtd_info->read = ram_read;
-   mtd_info->write = ram_write;
+  addr = vmalloc(MTDRAM_TOTAL_SIZE);
+  if (!addr) {
+    DEBUG(MTD_DEBUG_LEVEL1,
+          "Failed to vmalloc memory region of size %ld\n",
+          (long)MTDRAM_TOTAL_SIZE);
+    kfree(mtd_info);
+    mtd_info = NULL;
+    return -ENOMEM;
+  }
+  err = mtdram_init_device(mtd_info, addr,
+                           MTDRAM_TOTAL_SIZE, "mtdram test device");
+  if (err)
+  {
+    vfree(addr);
+    kfree(mtd_info);
+    mtd_info = NULL;
+    return err;
+  }
+  memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
+  return err;
+}
+#endif /* !(CONFIG_MTDRAM_ABS_POS > 0) */
+
+#else /* CONFIG_MTDRAM_TOTAL_SIZE > 0 */

-   if (add_mtd_device(mtd_info)) {
-#if CONFIG_MTDRAM_ABS_POS > 0
-     iounmap(mtd_info->priv);
-#else
-     vfree(mtd_info->priv);
-#endif
-     kfree(mtd_info);
-     mtd_info = NULL;
-     return -EIO;
-   }
-
-   return 0;
+int __init init_mtdram(void)
+{
+  return 0;
 }
+#endif /* !(CONFIG_MTDRAM_TOTAL_SIZE > 0) */

 module_init(init_mtdram);
 module_exit(cleanup_mtdram);
--- /dev/null Sat Mar 24 05:37:44 2001
+++ linux/include/linux/mtd/mtdram.h Mon May  6 10:02:26 2002
@@ -0,0 +1,10 @@
+#ifndef __MTD_MTDRAM_H__
+#define __MTD_MTDRAM_H__
+
+#ifdef __KERNEL__
+#include <linux/mtd/mtd.h>
+int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
+                       unsigned long size, char *name);
+
+#endif /* __KERNEL__ */
+#endif /* __MTD_MTDRAM_H__ */

--- linux/Documentation/Configure.help  23 Apr 2002 15:46:44 -0000      1.46
+++ linux/Documentation/Configure.help  6 May 2002 08:40:34 -0000
@@ -12639,9 +12639,9 @@ CONFIG_MTD_SLRAM

 Debugging RAM test driver
 CONFIG_MTD_MTDRAM
-  This enables a test MTD device driver which uses vmalloc() to
-  provide storage.  You probably want to say 'N' unless you're
-  testing stuff.
+  This enables a test MTD device driver which uses vmalloc()
+  or an absolute address to provide storage.
+  You probably want to say 'N' unless you're testing stuff.

 MTDRAM erase block size in KB
 CONFIG_MTDRAM_ERASE_SIZE
@@ -12656,6 +12656,8 @@ CONFIG_MTDRAM_TOTAL_SIZE
   emulated by the MTDRAM driver.  If the MTDRAM driver is built
   as a module, it is also possible to specify this as a parameter when
   loading the module.
+  If you want to set the size and position at runtime, set to 0,
+  in that case set the ABS_POS parameter to 0 as well.

 SRAM Hexadecimal Absolute position or 0
 CONFIG_MTDRAM_ABS_POS