ARM: uniphier: reserve memory for DRAM PHY training on PH1-LD20

The DRAM PHY layer on PH1-LD20 is able to calibrate PHY parameters
periodically.  This compensates for the voltage and temperature
deviation and improves the PHY parameter adjustment.  Instead, it
requires 64 byte scratch memory in each DRAM channel for the dynamic
training.  The memory regions must be reserved in DT before jumping
to the kernel.

The scratch area can be anywhere in each DRAM channel, but the DRAM
init code in SPL currently assigns it at the end of each channel.
So, it makes sense to reserve the regions on run-time by U-Boot
instead of statically embedding it in the DT in Linux.  Anyway,
a boot-loader should know much more about memory initialization
than the kernel.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

arch/arm/Kconfig

@@ -827,6 +827,7 @@ config ARCH_UNIPHIER
 	select SPL
 	select OF_CONTROL
 	select SPL_OF_CONTROL
+	select OF_LIBFDT
 	select DM
 	select SPL_DM
 	select DM_GPIO

arch/arm/mach-uniphier/Kconfig

@@ -40,6 +40,7 @@ config ARCH_UNIPHIER_LD11
 config ARCH_UNIPHIER_LD20
 	bool "UniPhier PH1-LD20 SoC"
 	select ARCH_UNIPHIER_64BIT
+	select OF_BOARD_SETUP
 
 endchoice
 

arch/arm/mach-uniphier/dram_init.c

@@ -9,6 +9,9 @@
 #include <fdtdec.h>
 #include <linux/err.h>
 
+#include "init.h"
+#include "soc-info.h"
+
 DECLARE_GLOBAL_DATA_PTR;
 
 static const void *get_memory_reg_prop(const void *fdt, int *lenp)
@@ -81,3 +84,40 @@ void dram_init_banksize(void)
 		      (unsigned long)gd->bd->bi_dram[i].size);
 	}
 }
+
+#ifdef CONFIG_OF_BOARD_SETUP
+/*
+ * The DRAM PHY requires 64 byte scratch area in each DRAM channel
+ * for its dynamic PHY training feature.
+ */
+int ft_board_setup(void *fdt, bd_t *bd)
+{
+	const struct uniphier_board_data *param;
+	unsigned long rsv_addr;
+	const unsigned long rsv_size = 64;
+	int ch, ret;
+
+	if (uniphier_get_soc_type() != SOC_UNIPHIER_LD20)
+		return 0;
+
+	param = uniphier_get_board_param();
+	if (!param) {
+		printf("failed to get board parameter\n");
+		return -ENODEV;
+	}
+
+	for (ch = 0; ch < param->dram_nr_ch; ch++) {
+		rsv_addr = param->dram_ch[ch].base + param->dram_ch[ch].size;
+		rsv_addr -= rsv_size;
+
+		ret = fdt_add_mem_rsv(fdt, rsv_addr, rsv_size);
+		if (ret)
+			return -ENOSPC;
+
+		printf("   Reserved memory region for DRAM PHY training: addr=%lx size=%lx\n",
+		       rsv_addr, rsv_size);
+	}
+
+	return 0;
+}
+#endif