max size of MTD?

max size of MTD?

[Seongsu Lee]

Hi,

What is the max size of a partition that can be used in MTD?
I found that the u_int32_t is used for the variable size 
in mtd_info. Then, I think 4GB is currently the max size. 
Am I right? 

I want to use 6GB flash memory with a partition. How can I 
fix it for using more than 4GB? I changed u_int32_t into
u_int64_t but it does not work. (kernel oops)


-- 
Seongsu's blog - http://www.senux.com/
"Besides, I think [Slackware] sounds better than
'Microsoft,' don't you?" (By Patrick Volkerding)

Re: max size of MTD?

[Seongsu Lee]

On Fri, Jan 05, 2007 at 04:29:41PM +0900, Seongsu Lee wrote:
> Hi,
> 
> What is the max size of a partition that can be used in MTD?
> I found that the u_int32_t is used for the variable size 
> in mtd_info. Then, I think 4GB is currently the max size. 
> Am I right? 
> 
> I want to use 6GB flash memory with a partition. How can I 
> fix it for using more than 4GB? I changed u_int32_t into
> u_int64_t but it does not work. (kernel oops)

Hi,

I changed the type of variable size in structure mtd_info 
from u_int32_t to u_int64_t. Some code such as printk is
modified after the change. It works. I tested that 
mtdconcat can create 6GB MTD device as one device.

-- 
Seongsu's blog - http://www.senux.com/
The aim of a joke is not to degrade the human being
but to remind him that he is already degraded. --
George Orwell

RE: max size of MTD?

[Vinit Agnihotri]

U have mentioned of creating 1 MTD device of 6GB by mtdconcat. However I am
curious to know how many mtd devices u've concatenated to make 6GB 
possible??? I am using mtdramm as test device but I am not able to allocate
memory over 1GB. So no question of having even more devices to make it above
5GB. Can you focus on the same question & help me. How can I allocate more
memory than 4GB??? Or how can I create 6GB MTD device.
My current test machine is AMD 64bit opteron with 1GB memory.

Thanks in advance.
Vinit.

-----Original Message-----
From: linux-mtd-bounces@lists.infradead.org
[mailto:linux-mtd-bounces@lists.infradead.org] On Behalf Of Seongsu Lee
Sent: Saturday, January 06, 2007 2:30 PM
To: linux-mtd@lists.infradead.org
Subject: Re: max size of MTD?

On Fri, Jan 05, 2007 at 04:29:41PM +0900, Seongsu Lee wrote:
> Hi,
> 
> What is the max size of a partition that can be used in MTD?
> I found that the u_int32_t is used for the variable size 
> in mtd_info. Then, I think 4GB is currently the max size. 
> Am I right? 
> 
> I want to use 6GB flash memory with a partition. How can I 
> fix it for using more than 4GB? I changed u_int32_t into
> u_int64_t but it does not work. (kernel oops)

Hi,

I changed the type of variable size in structure mtd_info 
from u_int32_t to u_int64_t. Some code such as printk is
modified after the change. It works. I tested that 
mtdconcat can create 6GB MTD device as one device.

-- 
Seongsu's blog - http://www.senux.com/
The aim of a joke is not to degrade the human being
but to remind him that he is already degraded. --
George Orwell

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

RE: max size of MTD?

[Josh Boyer]

On Mon, 2007-01-08 at 17:19 +0530, Vinit Agnihotri wrote:
> U have mentioned of creating 1 MTD device of 6GB by mtdconcat. However I am
> curious to know how many mtd devices u've concatenated to make 6GB
> possible??? I am using mtdramm as test device but I am not able to allocate
> memory over 1GB. So no question of having even more devices to make it above
> 5GB. Can you focus on the same question & help me. How can I allocate more
> memory than 4GB??? Or how can I create 6GB MTD device.
> My current test machine is AMD 64bit opteron with 1GB memory.

He has 6GiB of real flash memory, not DRAM.  Allocating more than 1GiB
of DRAM for mtdram will likely take more work.

josh

Re: max size of MTD?

[Seongsu Lee]

On Mon, Jan 08, 2007 at 05:19:25PM +0530, Vinit Agnihotri wrote:
> U have mentioned of creating 1 MTD device of 6GB by mtdconcat. However I am
> curious to know how many mtd devices u've concatenated to make 6GB 
> possible??? I am using mtdramm as test device but I am not able to allocate
> memory over 1GB. So no question of having even more devices to make it above
> 5GB. Can you focus on the same question & help me. How can I allocate more
> memory than 4GB??? Or how can I create 6GB MTD device.
> My current test machine is AMD 64bit opteron with 1GB memory.
> 
> Thanks in advance.
> Vinit.
 
Hi Vinit,

I have 6 physical flash memories in my test embedded board. The size 
of each flash memory is 1GB. The number of flash memory 
to be concatenated is 6. (1GB x 6 -> 6GB) I couldn't find out explicit 
limitation of number of devices to be concatenated by mtdconcat.

After receving your mail, I comfirmed that mtdconcat works at least
8 sub mtd devices. I created 8 mtd device based on RAM. (I mean mtdram.)
And I created a concatenated mtd device with 8 mtdram device.

[root@hybus ~]# cat /proc/mtd
dev:            size   erasesize  name
mtd0: 0000000000040000 00040000 "boot"
mtd1: 0000000000180000 00040000 "kernel"
mtd2: 0000000001e40000 00040000 "rootfs"
mtd3: 0000000000400000 00020000 "mtdram_test_1"
mtd4: 0000000000400000 00020000 "mtdram_test_2"
mtd5: 0000000000400000 00020000 "mtdram_test_3"
mtd6: 0000000000400000 00020000 "mtdram_test_4"
mtd7: 0000000000400000 00020000 "mtdram_test_5"
mtd8: 0000000000400000 00020000 "mtdram_test_6"
mtd9: 0000000000400000 00020000 "mtdram_test_7"
mtd10: 0000000000400000 00020000 "mtdram_test_8"
mtd11: 0000000002000000 00020000 "test_part_0"
[root@hybus ~]# mount -t jffs2 /dev/mtdblock11 /mnt/data11
[root@hybus ~]# df -h
Filesystem                Size      Used Available Use% Mounted on
/dev/rom2                30.3M     20.3M      9.9M  67% /
192.168.128.1:/nfs       28.9G     18.1G      9.3G  66% /mnt/nfs
/dev/mtdblock11          32.0M      1.0M     31.0M   3% /mnt/data11
[root@hybus ~]#

I think there is no limitation of number of sub mtd devices in code.
But you may not create more than 15 mtd devices in a system.

Max size of mtd device? I think it's 4GB. (u_int32_t size)

I really hope that my post can help you. 

Follow is a patch to create more than one mtdram device. I
worked linux kernel 2.6.11.

--- linux-2.6.11-test/drivers/mtd/devices/mtdram.c.mtdram_test 2006-11-18 20:14:38.000000000 +0900
+++ linux-2.6.11-test/drivers/mtd/devices/mtdram.c     2007-01-10 00:33:27.000000000 +0900
@@ -108,19 +108,24 @@
   return 0;
 }

+#define NUMRAM (8)
+static struct mtd_info *mtds[NUMRAM];
 static void __exit cleanup_mtdram(void)
 {
-  if (mtd_info) {
-    del_mtd_device(mtd_info);
+  int i;
+  for (i = 0; i < NUMRAM; i++) {
+  if (mtds[i]) {
+    del_mtd_device(mtds[i]);
 #if CONFIG_MTDRAM_TOTAL_SIZE > 0
-    if (mtd_info->priv)
+    if (mtds[i]->priv)
 #if CONFIG_MTDRAM_ABS_POS > 0
-      iounmap(mtd_info->priv);
+      iounmap(mtds[i]->priv);
 #else
-      vfree(mtd_info->priv);
+      vfree(mtds[i]->priv);
 #endif
 #endif
-    kfree(mtd_info);
+    kfree(mtds[i]);
+  }
   }
 }

@@ -186,9 +191,22 @@

 #else /* CONFIG_MTDRAM_ABS_POS > 0 */

+static int test(int n);
 static int __init init_mtdram(void)
 {
+       int i;
+       printk(KERN_INFO "%d mtdram test devices will be created.\n", NUMRAM);
+       for (i = 0; i < NUMRAM; i++) {
+               test(i);
+       }
+       return 0;
+}
+
+#define NAME_LEN (64)
+static int test(int n)
+{
   void *addr;
+  char *name;
   int err;
   /* Allocate some memory */
    mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
@@ -204,8 +222,10 @@
     mtd_info = NULL;
     return -ENOMEM;
   }
+  name = (char *)kmalloc(NAME_LEN, GFP_KERNEL);
+  snprintf(name, NAME_LEN - 1, "mtdram_test_%d", n + 1);
   err = mtdram_init_device(mtd_info, addr,
-                           MTDRAM_TOTAL_SIZE, "mtdram test device");
+                           MTDRAM_TOTAL_SIZE, name);
   if (err)
   {
     vfree(addr);
@@ -214,6 +234,7 @@
     return err;
   }
   memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
+  mtds[n] = mtd_info;
   return err;
 }
 #endif /* !(CONFIG_MTDRAM_ABS_POS > 0) */

> -----Original Message-----
> From: linux-mtd-bounces@lists.infradead.org
> [mailto:linux-mtd-bounces@lists.infradead.org] On Behalf Of Seongsu Lee
> Sent: Saturday, January 06, 2007 2:30 PM
> To: linux-mtd@lists.infradead.org
> Subject: Re: max size of MTD?
> 
> On Fri, Jan 05, 2007 at 04:29:41PM +0900, Seongsu Lee wrote:
> > Hi,
> > 
> > What is the max size of a partition that can be used in MTD?
> > I found that the u_int32_t is used for the variable size 
> > in mtd_info. Then, I think 4GB is currently the max size. 
> > Am I right? 
> > 
> > I want to use 6GB flash memory with a partition. How can I 
> > fix it for using more than 4GB? I changed u_int32_t into
> > u_int64_t but it does not work. (kernel oops)
> 
> Hi,
> 
> I changed the type of variable size in structure mtd_info 
> from u_int32_t to u_int64_t. Some code such as printk is
> modified after the change. It works. I tested that 
> mtdconcat can create 6GB MTD device as one device.

-- 
Seongsu's blog - http://www.senux.com/
How do I type "for i in *.dvi do xdvi i done" in a
GUI? (Discussion in comp.os.linux.misc on the
intuitiveness of interfaces.)

RE: max size of MTD?

[Vinit Agnihotri]

Thanks for your helpful reply. I was trying to allocate more than 1GB
through mtdram by using vmalloc, which is not possible as my physical ram is
1GB.

But thanks for detailed reply & patch.The patch will sure help me to work
with multiple mtdram & mtdconcat.

Thanks & Regards
Vinit.

-----Original Message-----
From: Seongsu Lee [mailto:senux@senux.com] 
Sent: Tuesday, January 09, 2007 9:25 PM
To: Vinit Agnihotri
Cc: linux-mtd@lists.infradead.org; jwboyer@linux.vnet.ibm.com
Subject: Re: max size of MTD?

On Mon, Jan 08, 2007 at 05:19:25PM +0530, Vinit Agnihotri wrote:
> U have mentioned of creating 1 MTD device of 6GB by mtdconcat. However I
am
> curious to know how many mtd devices u've concatenated to make 6GB 
> possible??? I am using mtdramm as test device but I am not able to
allocate
> memory over 1GB. So no question of having even more devices to make it
above
> 5GB. Can you focus on the same question & help me. How can I allocate more
> memory than 4GB??? Or how can I create 6GB MTD device.
> My current test machine is AMD 64bit opteron with 1GB memory.
> 
> Thanks in advance.
> Vinit.
 
Hi Vinit,

I have 6 physical flash memories in my test embedded board. The size 
of each flash memory is 1GB. The number of flash memory 
to be concatenated is 6. (1GB x 6 -> 6GB) I couldn't find out explicit 
limitation of number of devices to be concatenated by mtdconcat.

After receving your mail, I comfirmed that mtdconcat works at least
8 sub mtd devices. I created 8 mtd device based on RAM. (I mean mtdram.)
And I created a concatenated mtd device with 8 mtdram device.

[root@hybus ~]# cat /proc/mtd
dev:            size   erasesize  name
mtd0: 0000000000040000 00040000 "boot"
mtd1: 0000000000180000 00040000 "kernel"
mtd2: 0000000001e40000 00040000 "rootfs"
mtd3: 0000000000400000 00020000 "mtdram_test_1"
mtd4: 0000000000400000 00020000 "mtdram_test_2"
mtd5: 0000000000400000 00020000 "mtdram_test_3"
mtd6: 0000000000400000 00020000 "mtdram_test_4"
mtd7: 0000000000400000 00020000 "mtdram_test_5"
mtd8: 0000000000400000 00020000 "mtdram_test_6"
mtd9: 0000000000400000 00020000 "mtdram_test_7"
mtd10: 0000000000400000 00020000 "mtdram_test_8"
mtd11: 0000000002000000 00020000 "test_part_0"
[root@hybus ~]# mount -t jffs2 /dev/mtdblock11 /mnt/data11
[root@hybus ~]# df -h
Filesystem                Size      Used Available Use% Mounted on
/dev/rom2                30.3M     20.3M      9.9M  67% /
192.168.128.1:/nfs       28.9G     18.1G      9.3G  66% /mnt/nfs
/dev/mtdblock11          32.0M      1.0M     31.0M   3% /mnt/data11
[root@hybus ~]#

I think there is no limitation of number of sub mtd devices in code.
But you may not create more than 15 mtd devices in a system.

Max size of mtd device? I think it's 4GB. (u_int32_t size)

I really hope that my post can help you. 

Follow is a patch to create more than one mtdram device. I
worked linux kernel 2.6.11.

--- linux-2.6.11-test/drivers/mtd/devices/mtdram.c.mtdram_test 2006-11-18
20:14:38.000000000 +0900
+++ linux-2.6.11-test/drivers/mtd/devices/mtdram.c     2007-01-10
00:33:27.000000000 +0900
@@ -108,19 +108,24 @@
   return 0;
 }

+#define NUMRAM (8)
+static struct mtd_info *mtds[NUMRAM];
 static void __exit cleanup_mtdram(void)
 {
-  if (mtd_info) {
-    del_mtd_device(mtd_info);
+  int i;
+  for (i = 0; i < NUMRAM; i++) {
+  if (mtds[i]) {
+    del_mtd_device(mtds[i]);
 #if CONFIG_MTDRAM_TOTAL_SIZE > 0
-    if (mtd_info->priv)
+    if (mtds[i]->priv)
 #if CONFIG_MTDRAM_ABS_POS > 0
-      iounmap(mtd_info->priv);
+      iounmap(mtds[i]->priv);
 #else
-      vfree(mtd_info->priv);
+      vfree(mtds[i]->priv);
 #endif
 #endif
-    kfree(mtd_info);
+    kfree(mtds[i]);
+  }
   }
 }

@@ -186,9 +191,22 @@

 #else /* CONFIG_MTDRAM_ABS_POS > 0 */

+static int test(int n);
 static int __init init_mtdram(void)
 {
+       int i;
+       printk(KERN_INFO "%d mtdram test devices will be created.\n",
NUMRAM);
+       for (i = 0; i < NUMRAM; i++) {
+               test(i);
+       }
+       return 0;
+}
+
+#define NAME_LEN (64)
+static int test(int n)
+{
   void *addr;
+  char *name;
   int err;
   /* Allocate some memory */
    mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
@@ -204,8 +222,10 @@
     mtd_info = NULL;
     return -ENOMEM;
   }
+  name = (char *)kmalloc(NAME_LEN, GFP_KERNEL);
+  snprintf(name, NAME_LEN - 1, "mtdram_test_%d", n + 1);
   err = mtdram_init_device(mtd_info, addr,
-                           MTDRAM_TOTAL_SIZE, "mtdram test device");
+                           MTDRAM_TOTAL_SIZE, name);
   if (err)
   {
     vfree(addr);
@@ -214,6 +234,7 @@
     return err;
   }
   memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
+  mtds[n] = mtd_info;
   return err;
 }
 #endif /* !(CONFIG_MTDRAM_ABS_POS > 0) */

> -----Original Message-----
> From: linux-mtd-bounces@lists.infradead.org
> [mailto:linux-mtd-bounces@lists.infradead.org] On Behalf Of Seongsu Lee
> Sent: Saturday, January 06, 2007 2:30 PM
> To: linux-mtd@lists.infradead.org
> Subject: Re: max size of MTD?
> 
> On Fri, Jan 05, 2007 at 04:29:41PM +0900, Seongsu Lee wrote:
> > Hi,
> > 
> > What is the max size of a partition that can be used in MTD?
> > I found that the u_int32_t is used for the variable size 
> > in mtd_info. Then, I think 4GB is currently the max size. 
> > Am I right? 
> > 
> > I want to use 6GB flash memory with a partition. How can I 
> > fix it for using more than 4GB? I changed u_int32_t into
> > u_int64_t but it does not work. (kernel oops)
> 
> Hi,
> 
> I changed the type of variable size in structure mtd_info 
> from u_int32_t to u_int64_t. Some code such as printk is
> modified after the change. It works. I tested that 
> mtdconcat can create 6GB MTD device as one device.

-- 
Seongsu's blog - http://www.senux.com/
How do I type "for i in *.dvi do xdvi i done" in a
GUI? (Discussion in comp.os.linux.misc on the
intuitiveness of interfaces.)