add new CONFIG_AT91_LEGACY
* add's the new temporary CONFIG_AT91_LEGACY to all board configs
This will need for backward compatiblity, while change the SoC access
to c structures. If CONFIG_AT91_LEGACY is defined, the deprecated
SoC is used.
Signed-off-by: Jens Scharsig <js_at_ng@scharsoft.de>
diff --git a/doc/README.at91-soc b/doc/README.at91-soc
new file mode 100644
index 0000000..bed035c
--- /dev/null
+++ b/doc/README.at91-soc
@@ -0,0 +1,41 @@
+ New C structure AT91 SoC access
+=================================
+
+The goal
+--------
+
+Currently the at91 arch uses hundreds of address defines and special
+at91_xxxx_write/read functions to access the SOC.
+The u-boot project perferred method is to access memory mapped hw
+regisister via a c structure.
+
+e.g. old
+
+ *AT91C_PIOA_IDR = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK;
+ *AT91C_PIOC_PUDR = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK;
+ *AT91C_PIOC_PER = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK;
+ *AT91C_PIOC_OER = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK;
+ *AT91C_PIOC_PIO = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK;
+
+ at91_sys_write(AT91_RSTC_CR,
+ AT91_RSTC_KEY | AT91_RSTC_PROCRST | AT91_RSTC_PERRST);
+
+e.g new
+ pin = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK;
+ writel(pin, &pio->pioa.idr);
+ writel(pin, &pio->pioa.pudr);
+ writel(pin, &pio->pioa.per);
+ writel(pin, &pio->pioa.oer);
+ writel(pin, &pio->pioa.sodr);
+
+ writel(AT91_RSTC_KEY | AT91_RSTC_CR_PROCRST |
+ AT91_RSTC_CR_PERRST, &rstc->cr);
+
+The method for updating
+------------------------
+
+1. add's the temporary CONFIG_AT91_LEGACY to all at91 board configs
+2. Display a compile time warning, if the board has not been converted
+3. add new structures for SoC access
+4. Convert arch, driver and boards file to new SoC
+5. remove legacy code, if all boards and drives are ready