[U-Boot] [PATCH 3/5] arc: emsdp: Read real CPU clock value from hardware

[Alexey Brodkin]

We do real CPU clock measurement with help of built-in
counters. Thus we may accommodate different real clock values
that appear in different FPA images instead of relying on
something hard-coded in the .dtb.

And while at it make make SDIO base address define
look similar to others with casting to "(void *)".

Signed-off-by: Alexey Brodkin <abrodkin at synopsys.com>
---
 board/synopsys/emsdp/emsdp.c | 42 +++++++++++++++++++++++++++++++++---
 1 file changed, 39 insertions(+), 3 deletions(-)

diff --git a/board/synopsys/emsdp/emsdp.c b/board/synopsys/emsdp/emsdp.c
index b5ec7f17ec1b..5ab44353746b 100644
--- a/board/synopsys/emsdp/emsdp.c
+++ b/board/synopsys/emsdp/emsdp.c
@@ -7,10 +7,46 @@
 #include <dwmmc.h>
 #include <malloc.h>
 
+#include <asm/arcregs.h>
+
 DECLARE_GLOBAL_DATA_PTR;
 
-#define ARC_PERIPHERAL_BASE	0xF0000000
-#define SDIO_BASE		(ARC_PERIPHERAL_BASE + 0x10000)
+#define ARC_PERIPHERAL_BASE		0xF0000000
+
+#define CGU_ARC_FMEAS_ARC		(void *)(ARC_PERIPHERAL_BASE + 0x84)
+#define CGU_ARC_FMEAS_ARC_START		BIT(31)
+#define CGU_ARC_FMEAS_ARC_DONE		BIT(30)
+#define CGU_ARC_FMEAS_ARC_CNT_MASK	GENMASK(14, 0)
+#define CGU_ARC_FMEAS_ARC_RCNT_OFFSET	0
+#define CGU_ARC_FMEAS_ARC_FCNT_OFFSET	15
+
+#define SDIO_BASE			(void *)(ARC_PERIPHERAL_BASE + 0x10000)
+
+int mach_cpu_init(void)
+{
+	int rcnt, fcnt;
+	u32 data;
+
+	/* Start frequency measurement */
+	writel(CGU_ARC_FMEAS_ARC_START, CGU_ARC_FMEAS_ARC);
+
+	/* Poll DONE bit */
+	do {
+		data = readl(CGU_ARC_FMEAS_ARC);
+	} while (!(data & CGU_ARC_FMEAS_ARC_DONE));
+
+	/* Amount of reference 100 MHz clocks */
+	rcnt = ((data >> CGU_ARC_FMEAS_ARC_RCNT_OFFSET) &
+	       CGU_ARC_FMEAS_ARC_CNT_MASK);
+
+	/* Amount of CPU clocks */
+	fcnt = ((data >> CGU_ARC_FMEAS_ARC_FCNT_OFFSET) &
+	       CGU_ARC_FMEAS_ARC_CNT_MASK);
+
+	gd->cpu_clk = ((100 * fcnt) / rcnt) * 1000000;
+
+	return 0;
+}
 
 int board_mmc_init(bd_t *bis)
 {
@@ -24,7 +60,7 @@ int board_mmc_init(bd_t *bis)
 
 	memset(host, 0, sizeof(struct dwmci_host));
 	host->name = "Synopsys Mobile storage";
-	host->ioaddr = (void *)SDIO_BASE;
+	host->ioaddr = SDIO_BASE;
 	host->buswidth = 4;
 	host->dev_index = 0;
 	host->bus_hz = 50000000;
-- 
2.19.1