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authorTom Rini <[email protected]>2021-10-06 12:26:33 -0400
committerTom Rini <[email protected]>2021-10-06 13:46:31 -0400
commitea67f467a43e4c8852bd1ce1bb75f5dc6c3788d1 (patch)
tree1bbf310f2b22ad465d5698bfdf71347129834561 /doc
parent7240e1b8f94a56db88a2af688cad27e2e6545302 (diff)
parent6115f1c4fe81015369e110ea9830a6e36710677c (diff)
Merge branch '2021-10-06-assorted-improvements'
- Use better values for ACPI OEM_VERSION - Assorted NAND related Kconifg migrations and another dependency fix
Diffstat (limited to 'doc')
-rw-r--r--doc/README.nand71
-rw-r--r--doc/develop/version.rst1
2 files changed, 0 insertions, 72 deletions
diff --git a/doc/README.nand b/doc/README.nand
index ec461b2dc93..ffcea907999 100644
--- a/doc/README.nand
+++ b/doc/README.nand
@@ -175,11 +175,6 @@ Configuration Options:
flexibility, so that one day we can eliminate the old mechanism.
- CONFIG_SYS_NAND_ONFI_DETECTION
- Enables detection of ONFI compliant devices during probe.
- And fetching device parameters flashed on device, by parsing
- ONFI parameter page.
-
Platform specific options
=========================
CONFIG_NAND_OMAP_GPMC
@@ -205,72 +200,6 @@ Platform specific options
so those platforms should use CONFIG_SPL_NAND_SIMPLE for enabling
SPL-NAND driver with software ECC correction support.
- CONFIG_NAND_OMAP_ECCSCHEME
- On OMAP platforms, this CONFIG specifies NAND ECC scheme.
- It can take following values:
- OMAP_ECC_HAM1_CODE_SW
- 1-bit Hamming code using software lib.
- (for legacy devices only)
- OMAP_ECC_HAM1_CODE_HW
- 1-bit Hamming code using GPMC hardware.
- (for legacy devices only)
- OMAP_ECC_BCH4_CODE_HW_DETECTION_SW
- 4-bit BCH code (unsupported)
- OMAP_ECC_BCH4_CODE_HW
- 4-bit BCH code (unsupported)
- OMAP_ECC_BCH8_CODE_HW_DETECTION_SW
- 8-bit BCH code with
- - ecc calculation using GPMC hardware engine,
- - error detection using software library.
- - requires CONFIG_BCH to enable software BCH library
- (For legacy device which do not have ELM h/w engine)
- OMAP_ECC_BCH8_CODE_HW
- 8-bit BCH code with
- - ecc calculation using GPMC hardware engine,
- - error detection using ELM hardware engine.
- OMAP_ECC_BCH16_CODE_HW
- 16-bit BCH code with
- - ecc calculation using GPMC hardware engine,
- - error detection using ELM hardware engine.
-
- How to select ECC scheme on OMAP and AMxx platforms ?
- -----------------------------------------------------
- Though higher ECC schemes have more capability to detect and correct
- bit-flips, but still selection of ECC scheme is dependent on following
- - hardware engines present in SoC.
- Some legacy OMAP SoC do not have ELM h/w engine thus such
- SoC cannot support BCHx_HW ECC schemes.
- - size of OOB/Spare region
- With higher ECC schemes, more OOB/Spare area is required to
- store ECC. So choice of ECC scheme is limited by NAND oobsize.
-
- In general following expression can help:
- NAND_OOBSIZE >= 2 + (NAND_PAGESIZE / 512) * ECC_BYTES
- where
- NAND_OOBSIZE = number of bytes available in
- OOB/spare area per NAND page.
- NAND_PAGESIZE = bytes in main-area of NAND page.
- ECC_BYTES = number of ECC bytes generated to
- protect 512 bytes of data, which is:
- 3 for HAM1_xx ecc schemes
- 7 for BCH4_xx ecc schemes
- 14 for BCH8_xx ecc schemes
- 26 for BCH16_xx ecc schemes
-
- example to check for BCH16 on 2K page NAND
- NAND_PAGESIZE = 2048
- NAND_OOBSIZE = 64
- 2 + (2048 / 512) * 26 = 106 > NAND_OOBSIZE
- Thus BCH16 cannot be supported on 2K page NAND.
-
- However, for 4K pagesize NAND
- NAND_PAGESIZE = 4096
- NAND_OOBSIZE = 224
- ECC_BYTES = 26
- 2 + (4096 / 512) * 26 = 210 < NAND_OOBSIZE
- Thus BCH16 can be supported on 4K page NAND.
-
-
CONFIG_NAND_OMAP_GPMC_PREFETCH
On OMAP platforms that use the GPMC controller
(CONFIG_NAND_OMAP_GPMC_PREFETCH), this options enables the code that
diff --git a/doc/develop/version.rst b/doc/develop/version.rst
index 8f3231b7611..5c9046aa17a 100644
--- a/doc/develop/version.rst
+++ b/doc/develop/version.rst
@@ -87,7 +87,6 @@ fields. For example::
#define U_BOOT_DATE "Jan 06 2021" (US format only)
#define U_BOOT_TIME "08:50:36" (24-hour clock)
#define U_BOOT_TZ "-0700" (Time zone in hours)
- #define U_BOOT_BUILD_DATE 0x20210106 (hex yyyymmdd format)
#define U_BOOT_EPOCH 1609948236
The Epoch is the number of seconds since midnight on 1/1/70. You can convert