7caa13fdd2
Using the example for reading a gpio, shows the problem. NULL should be the gpio number. Signed-off-by: Tom Rix <Tom.Rix@windriver.com> Acked-by: Dirk Behme <dirk.behme@googlemail.com>
160 lines
2.7 KiB
Plaintext
160 lines
2.7 KiB
Plaintext
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Summary
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=======
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This README is about U-Boot support for TI's ARM Cortex-A8 based OMAP3 [1]
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family of SoCs. TI's OMAP3 SoC family contains an ARM Cortex-A8. Additionally,
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some family members contain a TMS320C64x+ DSP and/or an Imagination SGX 2D/3D
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graphics processor and various other standard peripherals.
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Currently the following boards are supported:
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* OMAP3530 BeagleBoard [2]
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* Gumstix Overo [3]
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* TI EVM [4]
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* OpenPandora Ltd. Pandora [5]
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* TI/Logic PD Zoom MDK [6]
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* TI/Logic PD Zoom 2 [7]
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Toolchain
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=========
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While ARM Cortex-A8 support ARM v7 instruction set (-march=armv7a) we compile
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with -march=armv5 to allow more compilers to work. For U-Boot code this has
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no performance impact.
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Build
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=====
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* BeagleBoard:
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make omap3_beagle_config
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make
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* Gumstix Overo:
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make omap3_overo_config
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make
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* TI EVM:
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make omap3_evm_config
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make
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* Pandora:
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make omap3_pandora_config
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make
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* Zoom MDK:
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make omap3_zoom1_config
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make
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* Zoom 2:
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make omap3_zoom2_config
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make
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Custom commands
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===============
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To make U-Boot for OMAP3 support NAND device SW or HW ECC calculation, U-Boot
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for OMAP3 supports custom user command
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nandecc hw/sw
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To be compatible with NAND drivers using SW ECC (e.g. kernel code)
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nandecc sw
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enables SW ECC calculation. HW ECC enabled with
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nandecc hw
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is typically used to write 2nd stage bootloader (known as 'x-loader') which is
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executed by OMAP3's boot rom and therefore has to be written with HW ECC.
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For all other commands see
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help
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Interfaces
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==========
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gpio
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To set a bit :
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if (!omap_request_gpio(N)) {
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omap_set_gpio_direction(N, 0);
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omap_set_gpio_dataout(N, 1);
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}
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To clear a bit :
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if (!omap_request_gpio(N)) {
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omap_set_gpio_direction(N, 0);
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omap_set_gpio_dataout(N, 0);
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}
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To read a bit :
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if (!omap_request_gpio(N)) {
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omap_set_gpio_direction(N, 1);
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val = omap_get_gpio_datain(N);
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omap_free_gpio(N);
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}
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if (val)
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printf("GPIO N is set\n");
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else
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printf("GPIO N is clear\n");
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Acknowledgements
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================
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OMAP3 U-Boot is based on U-Boot tar ball [8] for BeagleBoard and EVM done by
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several TI employees.
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Links
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=====
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[1] OMAP3:
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http://www.ti.com/omap3 (high volume) and
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http://www.ti.com/omap35x (broad market)
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[2] OMAP3530 BeagleBoard:
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http://beagleboard.org/
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[3] Gumstix Overo:
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http://www.gumstix.net/Overo/
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[4] TI EVM:
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http://focus.ti.com/docs/toolsw/folders/print/tmdxevm3503.html
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[5] OpenPandora Ltd. Pandora:
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http://openpandora.org/
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[6] TI/Logic PD Zoom MDK:
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http://www.logicpd.com/products/devkit/ti/zoom_mobile_development_kit
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[7] TI/Logic PD Zoom 2
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http://www.logicpd.com/sites/default/files/1012659A_Zoom_OMAP34x-II_MDP_Brief.pdf
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[8] TI OMAP3 U-Boot:
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http://beagleboard.googlecode.com/files/u-boot_beagle_revb.tar.gz
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