For i.MX7 U-Boot initializes the system counter. On i.MX6 Barebox is
often used which doesn't initialize the counter. With this patch, we try
to auto-detect whether the counter is initialized or not and do the
initialization ourself if necessary.
Closes #3869
---
bsps/arm/imx/start/bspstart.c | 61 ++++++++++++++++++++++++++++++++++-
1 file changed, 60 insertions(+), 1 deletion(-)
diff --git a/bsps/arm/imx/start/bspstart.c b/bsps/arm/imx/start/bspstart.c
index 9f610d1ff5..238bc2bd28 100644
--- a/bsps/arm/imx/start/bspstart.c
+++ b/bsps/arm/imx/start/bspstart.c
@@ -19,6 +19,7 @@
#include <bsp/irq-generic.h>
#include <bsp/linker-symbols.h>
#include <dev/clock/arm-generic-timer.h>
+#include <libcpu/arm-cp15.h>
#include <libfdt.h>
@@ -59,6 +60,60 @@ uint32_t bsp_fdt_map_intr(const uint32_t *intr, size_t
icells)
return intr[1] + MAGIC_IRQ_OFFSET;
}
+static bool imx_is_imx6(const void *fdt)
+{
+ /*
+ * At the moment: Check for some compatible strings that should be there
+ * somewhere in every fdt.
+ *
+ * FIXME: It would be nice if some CPU-ID could be used instead. But I didn't
+ * find one.
+ */
+ int node;
+
+ node = fdt_node_offset_by_compatible(fdt, -1, "fsl,imx6ul");
+ if (node >= 0) {
+ return true;
+ }
+
+ node = fdt_node_offset_by_compatible(fdt, -1, "fsl,imx6ull");
+ if (node >= 0) {
+ return true;
+ }
+
+ return false;
+}
+
+#define SYSCNT_CNTCR (0x0)
+#define SYSCNT_CNTCR_ENABLE (1 << 0)
+#define SYSCNT_CNTCR_HDBG (1 << 1)
+#define SYSCNT_CNTCR_FCREQ(n) (1 << (8 + (n)))
+#define SYSCNT_CNTFID(n) (0x20 + 4 * (n))
+
+static uint32_t imx_syscnt_enable_and_return_frequency(const void *fdt)
+{
+ uint32_t freq;
+ volatile void *syscnt_base;
+
+ /* That's not in the usual FDTs. Sorry for falling back to a magic value. */
+ if (imx_is_imx6(fdt)) {
+ syscnt_base = (void *)0x021dc000;
+ } else {
+ syscnt_base = (void *)0x306c0000;
+ }
+
+ freq = *(uint32_t *)(syscnt_base + SYSCNT_CNTFID(0));
+
+ arm_cp15_set_counter_frequency(freq);
+
+ *(uint32_t *)(syscnt_base + SYSCNT_CNTCR) =
+ SYSCNT_CNTCR_ENABLE |
+ SYSCNT_CNTCR_HDBG |
+ SYSCNT_CNTCR_FCREQ(0);
+
+ return freq;
+}
+
void arm_generic_timer_get_config(
uint32_t *frequency,
uint32_t *irq
@@ -76,7 +131,11 @@ void arm_generic_timer_get_config(
if (val != NULL && len >= 4) {
*frequency = fdt32_to_cpu(val[0]);
} else {
- bsp_fatal(IMX_FATAL_GENERIC_TIMER_FREQUENCY);
+ /*
+ * Normally clock-frequency would be provided by the boot loader. If it
+ * didn't add one, we have to initialize the system counter ourself.
+ */
+ *frequency = imx_syscnt_enable_and_return_frequency(fdt);
}
/* FIXME: Figure out how Linux gets a proper IRQ number */
--
2.26.2
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