@@ -74,6 +74,34 @@ void omap_prcm_arch_reset(char mode, const char *cmd)
WARN_ON(1);
}
+ /*
+ * As per Errata i520, in some cases, user will not be able to
+ * access DDR memory after warm-reset.
+ * This situation occurs while the warm-reset happens during a read
+ * access to DDR memory. In that particular condition, DDR memory
+ * does not respond to a corrupted read command due to the warm
+ * reset occurrence but SDRC is waiting for read completion.
+ * SDRC is not sensitive to the warm reset, but the interconnect is
+ * reset on the fly, thus causing a misalignment between SDRC logic,
+ * interconnect logic and DDR memory state.
+ * WORKAROUND:
+ * Steps to perform before a Warm reset is trigged:
+ * 1. enable self-refresh on idle request
+ * 2. put SDRC in idle
+ * 3. wait until SDRC goes to idle
+ * 4. generate SW reset (Global SW reset)
+ *
+ * Steps to be performed after warm reset occurs (in bootloader):
+ * if HW warm reset is the source, apply below steps before any
+ * accesses to SDRAM:
+ * 1. Reset SMS and SDRC and wait till reset is complete
+ * 2. Re-initialize SMS, SDRC and memory
+ *
+ * NOTE: Above work around is required only if arch reset is implemented
+ * using Global SW reset(GLOBAL_SW_RST). DPLL3 reset does not need
+ * the WA since it resets SDRC as well as part of cold reset.
+ */
+
/* XXX should be moved to some OMAP2/3 specific code */
omap2_prm_set_mod_reg_bits(OMAP_RST_DPLL3_MASK, prcm_offs,
OMAP2_RM_RSTCTRL);