Changes between Version 16 and Version 17 of linux/ubi

Timestamp:

04/24/2019 08:38:20 PM (6 years ago)

Author:

Tim Harvey

Comment:

added details on how to determine FLASH geometry at runtime from U-Boot and Linux

linux/ubi

@@ -26 +26 @@
  * The 'Page Size', 'Block Size', and max blocks are specified by the NAND datasheet. The Logical Erase Block size can be calculated as: (Block Size) - 2 * (Page Size)
 
+The geometry can also be determined at runtime in U-Boot using {{{nand info}}} and Linux using {{{sysfs}}}:
+ * Cypress S34ML16G202 2GiB FLASH:
+  - U-Boot:
+{{{#!bash
+Ventana > nand info
+
+Device 0: nand0, sector size 256 KiB
+  Page size       4096 b
+  OOB size         224 b
+  Erase size    262144 b
+  subpagesize     4096 b
+  options     0x40000200
+  bbt options 0x       0
+}}}
+   * U-Boot above shows a 4096 byte page size and a 256KiB erase block size which dictates a 248KiB logical erase block size
+  - Linux (once device is attached via 'ubiattach /dev/ubi_ctrl -m 2' or via 'root=ubi  ubi=2' kernel cmdline params:
+{{{#!bash
+# cat /sys/devices/virtual/ubi/ubi0/min_io_size 
+4096
+# cat /sys/devices/virtual/ubi/ubi0/eraseblock_size 
+253952
+# cat /sys/devices/virtual/ubi/ubi0/total_eraseblocks 
+8124
+}}}
+   * above shows a 4096 byte page size, a 248KiB logical erase block size (which dictates a 256KiB physical erase block size) and a max of 8124 total erase blocks available in this ubi for a total usable space of 8124*248KiB still available for use by ubi volumes
+ * Micron MT29F2G08 256MiB FLASH:
+  - U-Boot:
+{{{#!bash
+Ventana > nand info
+
+Device 0: nand0, sector size 128 KiB
+  Page size       2048 b
+  OOB size         128 b
+  Erase size    131072 b
+  subpagesize     2048 b
+  options     0x40000200
+  bbt options 0x    8000
+}}}
+   * U-Boot aqbove shows a 2048 byte page size and a 128KiB erase block size which dictates a 124KiB logical erase block size
+  - Linux (once device is attached via 'ubiattach /dev/ubi_ctrl -m 2' or via 'root=ubi  ubi=2' kernel cmdline params:
+{{{#!bash
+# cat /sys/devices/virtual/ubi/ubi0/min_io_size 
+2048
+# cat /sys/devices/virtual/ubi/ubi0/eraseblock_size 
+126976
+# cat /sys/devices/virtual/ubi/ubi0/total_eraseblocks 
+16248
+}}}
+   * above shows a 2048 byte page size, a 124KiB logical erase block size (which dictates a 128KiB physical erase block size) and a max of 126976 total erase blocks available in this ubi for a total usable space of 126976*124KiB still available for use by ubi volumes
 
 mkfs.ubifs important arguments: