i.MX28: Improve passing of data from SPL to U-Boot

Pass memory size from SPL via structure located in SRAM instead of SCRATCH
registers. This allows passing more data about boot from SPL to U-Boot, like the
boot mode pads configuration.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Detlev Zundel <dzu@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Wolfgang Denk <wd@denx.de>

arch/arm/cpu/arm926ejs/mx28/mx28.c

@@ -279,22 +279,16 @@ void imx_get_mac_from_fuse(int dev_id, unsigned char *mac)
 
 int mx28_dram_init(void)
 {
-	struct mx28_digctl_regs *digctl_regs =
-		(struct mx28_digctl_regs *)MXS_DIGCTL_BASE;
-	uint32_t sz[2];
+	struct mx28_spl_data *data = (struct mx28_spl_data *)
+		((CONFIG_SYS_TEXT_BASE - sizeof(struct mx28_spl_data)) & ~0xf);
 
-	sz[0] = readl(&digctl_regs->hw_digctl_scratch0);
-	sz[1] = readl(&digctl_regs->hw_digctl_scratch1);
-
-	if (sz[0] != sz[1]) {
+	if (data->mem_dram_size == 0) {
 		printf("MX28:\n"
-			"Error, the RAM size in HW_DIGCTRL_SCRATCH0 and\n"
-			"HW_DIGCTRL_SCRATCH1 is not the same. Please\n"
-			"verify these two registers contain valid RAM size!\n");
+			"Error, the RAM size passed up from SPL is 0!\n");
 		hang();
 	}
 
-	gd->ram_size = sz[0];
+	gd->ram_size = data->mem_dram_size;
 	return 0;
 }
 

arch/arm/cpu/arm926ejs/mx28/mx28_init.h

@@ -37,5 +37,6 @@ static inline void mx28_power_wait_pswitch(void) { }
 #endif
 
 void mx28_mem_init(void);
+uint32_t mx28_mem_get_size(void);
 
 #endif	/* __M28_INIT_H__ */

arch/arm/cpu/arm926ejs/mx28/spl_boot.c

@@ -28,6 +28,7 @@
 #include <asm/io.h>
 #include <asm/arch/iomux-mx28.h>
 #include <asm/arch/imx-regs.h>
+#include <asm/arch/sys_proto.h>
 
 #include "mx28_init.h"
 
@@ -49,9 +50,15 @@ void early_delay(int delay)
 void mx28_common_spl_init(const iomux_cfg_t *iomux_setup,
 			const unsigned int iomux_size)
 {
+	struct mx28_spl_data *data = (struct mx28_spl_data *)
+		((CONFIG_SYS_TEXT_BASE - sizeof(struct mx28_spl_data)) & ~0xf);
+
 	mxs_iomux_setup_multiple_pads(iomux_setup, iomux_size);
 	mx28_power_init();
+
 	mx28_mem_init();
+	data->mem_dram_size = mx28_mem_get_size();
+
 	mx28_power_wait_pswitch();
 }
 

arch/arm/cpu/arm926ejs/mx28/spl_mem_init.c

@@ -175,10 +175,8 @@ void mx28_mem_setup_vddd(void)
 		&power_regs->hw_power_vdddctrl);
 }
 
-void mx28_mem_get_size(void)
+uint32_t mx28_mem_get_size(void)
 {
-	struct mx28_digctl_regs *digctl_regs =
-		(struct mx28_digctl_regs *)MXS_DIGCTL_BASE;
 	uint32_t sz, da;
 	uint32_t *vt = (uint32_t *)0x20;
 	/* The following is "subs pc, r14, #4", used as return from DABT. */
@@ -189,11 +187,11 @@ void mx28_mem_get_size(void)
 	vt[4] = data_abort_memdetect_handler;
 
 	sz = get_ram_size((long *)PHYS_SDRAM_1, PHYS_SDRAM_1_SIZE);
-	writel(sz, &digctl_regs->hw_digctl_scratch0);
-	writel(sz, &digctl_regs->hw_digctl_scratch1);
 
 	/* Restore the old DABT handler. */
 	vt[4] = da;
+
+	return sz;
 }
 
 void mx28_mem_init(void)
@@ -241,6 +239,4 @@ void mx28_mem_init(void)
 	early_delay(10000);
 
 	mx28_mem_setup_cpu_and_hbus();
-
-	mx28_mem_get_size();
 }

arch/arm/include/asm/arch-mx28/sys_proto.h

@@ -39,6 +39,10 @@ void mx28_common_spl_init(const iomux_cfg_t *iomux_setup,
 			const unsigned int iomux_size);
 #endif
 
+struct mx28_spl_data {
+	uint32_t	mem_dram_size;
+};
+
 int mx28_dram_init(void);
 
 #endif	/* __MX28_H__ */