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drivers: eeprom: EEPROM emulation in flash memory

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This driver emulates a EEPROM device in flash.

Reworked implementation with modified flash layout.

The emulation represents the EEPROM in flash as a region that is a
direct map of the eeprom data followed by a region where changes to
the eeprom data is stored. Changes are written as address-data
combinations. The size of such a combination is determined by the
flash write block size and the size of the eeprom (required address
space), with a minimum of 4 byte.
The eeprom page needs to be a multiple of the flash page. Multiple
eeprom pages is also so supported and increases the number of writes
that can be performed.

The eeprom size, pagesize and the flash partition used for the eeprom
are defined in the dts. The flash partition should allow at least two
eeprom pages. For fast read access a rambuffer can be enabled for the
eeprom (by setting the option rambuf in the dts).

Signed-off-by: Laczen JMS <laczenjms@gmail.com>
This commit is contained in:
Laczen JMS 2020-12-14 14:47:06 +01:00 • committed by Carles Cufí
commit 232272cff8
8 changed files with 919 additions and 19 deletions
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20
boards/x86/qemu_x86/qemu_x86.dts
View file

@ -27,6 +27,7 @@
uart-0 = &uart0;
uart-1 = &uart1;
eeprom-0 = &eeprom0;
eeprom-1 = &eeprom1;
};
chosen {
@ -70,12 +71,23 @@
};
};
eeprom0: eeprom {
eeprom1: eeprom1 {
status = "okay";
compatible = "zephyr,emu-eeprom";
label = "EEPROM_1";
size = <DT_SIZE_K(4)>;
pagesize = <DT_SIZE_K(8)>;
partition = <&eepromemu_partition>;
rambuf;
};
eeprom0: eeprom0 {
status = "okay";
compatible = "zephyr,sim-eeprom";
label = "EEPROM_0";
size = <DT_SIZE_K(32)>;
size = <DT_SIZE_K(4)>;
};
};
&uart0 {
@ -116,5 +128,9 @@
label = "image-1";
reg = <0x00021000 0x00010000>;
};
eepromemu_partition: partition@31000 {
label = "eeprom-emu";
reg = <0x00031000 0x00010000>;
};
};
};