zynqmp: spl: support DRAM ECC initialization

Use the ZDMA channel 0 to initialize the DRAM banks. This avoid
spurious ECC errors that can occur when accessing unitialized memory.

The feature is enabled by setting the option
CONFIG_SPL_ZYNQMP_DRAM_ECC_INIT and providing the following data:

 SPL_ZYNQMP_DRAM_BANK1_BASE: start of memory to initialize
 SPL_ZYNQMP_DRAM_BANK1_LEN : len of memory to initialize (hex)
 SPL_ZYNQMP_DRAM_BANK2_BASE: start of memory to initialize
 SPL_ZYNQMP_DRAM_BANK2_LEN : len of memory to initialize (hex)

Setting SPL_ZYNQMP_DRAM_BANK_LEN to 0 takes no action.

Signed-off-by: Jorge Ramirez-Ortiz <jorge@foundries.io>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/arm/mach-zynqmp/Kconfig

@@ -92,6 +92,41 @@ config ZYNQMP_NO_DDR
 	  This option configures MMU with no DDR to avoid speculative
 	  access to DDR memory where DDR is not present.
 
+config SPL_ZYNQMP_DRAM_ECC_INIT
+	bool "Initialize DRAM ECC"
+	depends on SPL
+	help
+	  This option initializes all memory to 0xdeadbeef. Must be set if your
+	  memory is of ECC type.
+
+config SPL_ZYNQMP_DRAM_BANK1_BASE
+	depends on SPL_ZYNQMP_DRAM_ECC_INIT
+	hex "DRAM Bank1 address"
+       default 0x00000000
+       help
+         Start address of DRAM ECC bank1
+
+config SPL_ZYNQMP_DRAM_BANK1_LEN
+	depends on SPL_ZYNQMP_DRAM_ECC_INIT
+	hex "DRAM Bank1 size"
+       default 0x80000000
+       help
+         Size in bytes of the DRAM ECC bank1
+
+config SPL_ZYNQMP_DRAM_BANK2_BASE
+	depends on SPL_ZYNQMP_DRAM_ECC_INIT
+	hex "DRAM Bank2 address"
+       default 0x800000000
+       help
+         Start address of DRAM ECC bank2
+
+config SPL_ZYNQMP_DRAM_BANK2_LEN
+	depends on SPL_ZYNQMP_DRAM_ECC_INIT
+	hex "DRAM Bank2 size"
+       default 0x0
+       help
+         Size in bytes of the DRAM ECC bank2. A null size takes no action.
+
 config SYS_MALLOC_F_LEN
 	default 0x600
 

arch/arm/mach-zynqmp/Makefile

@@ -7,4 +7,5 @@ obj-y	+= clk.o
 obj-y	+= cpu.o
 obj-$(CONFIG_MP)	+= mp.o
 obj-$(CONFIG_SPL_BUILD) += spl.o handoff.o
+obj-$(CONFIG_SPL_ZYNQMP_DRAM_ECC_INIT) += ecc_spl_init.o
 obj-$(CONFIG_ZYNQMP_PSU_INIT_ENABLED)	+= psu_spl_init.o

arch/arm/mach-zynqmp/ecc_spl_init.c

@@ -0,0 +1,163 @@
+// SPDX-License-Identifier: MIT
+/*
+ *  Copyright(c) 2015 - 2020 Xilinx, Inc.
+ *
+ *  Jorge Ramirez-Ortiz <jorge@foundries.io>
+ */
+
+#include <common.h>
+#include <cpu_func.h>
+#include <asm/arch/hardware.h>
+#include <asm/arch/ecc_spl_init.h>
+#include <asm/io.h>
+#include <linux/delay.h>
+
+#define ZDMA_TRANSFER_MAX_LEN		(0x3FFFFFFFU - 7U)
+#define ZDMA_CH_STATUS			((ADMA_CH0_BASEADDR) + 0x0000011CU)
+#define ZDMA_CH_STATUS_STATE_MASK	0x00000003U
+#define ZDMA_CH_STATUS_STATE_DONE	0x00000000U
+#define ZDMA_CH_STATUS_STATE_ERR	0x00000003U
+#define ZDMA_CH_CTRL0			((ADMA_CH0_BASEADDR) + 0x00000110U)
+#define ZDMA_CH_CTRL0_POINT_TYPE_MASK	(u32)0x00000040U
+#define ZDMA_CH_CTRL0_POINT_TYPE_NORMAL	(u32)0x00000000U
+#define ZDMA_CH_CTRL0_MODE_MASK		(u32)0x00000030U
+#define ZDMA_CH_CTRL0_MODE_WR_ONLY	(u32)0x00000010U
+#define ZDMA_CH_CTRL0_TOTAL_BYTE_COUNT	((ADMA_CH0_BASEADDR) + 0x00000188U)
+#define ZDMA_CH_WR_ONLY_WORD0		((ADMA_CH0_BASEADDR) + 0x00000148U)
+#define ZDMA_CH_WR_ONLY_WORD1		((ADMA_CH0_BASEADDR) + 0x0000014CU)
+#define ZDMA_CH_WR_ONLY_WORD2		((ADMA_CH0_BASEADDR) + 0x00000150U)
+#define ZDMA_CH_WR_ONLY_WORD3		((ADMA_CH0_BASEADDR) + 0x00000154U)
+#define ZDMA_CH_DST_DSCR_WORD0		((ADMA_CH0_BASEADDR) + 0x00000138U)
+#define ZDMA_CH_DST_DSCR_WORD0_LSB_MASK	0xFFFFFFFFU
+#define ZDMA_CH_DST_DSCR_WORD1		((ADMA_CH0_BASEADDR) + 0x0000013CU)
+#define ZDMA_CH_DST_DSCR_WORD1_MSB_MASK	0x0001FFFFU
+#define ZDMA_CH_SRC_DSCR_WORD2		((ADMA_CH0_BASEADDR) + 0x00000130U)
+#define ZDMA_CH_DST_DSCR_WORD2		((ADMA_CH0_BASEADDR) + 0x00000140U)
+#define ZDMA_CH_CTRL2			((ADMA_CH0_BASEADDR) + 0x00000200U)
+#define ZDMA_CH_CTRL2_EN_MASK		0x00000001U
+#define ZDMA_CH_ISR			((ADMA_CH0_BASEADDR) + 0x00000100U)
+#define ZDMA_CH_ISR_DMA_DONE_MASK	0x00000400U
+#define ECC_INIT_VAL_WORD		0xDEADBEEFU
+
+#define ZDMA_IDLE_TIMEOUT_USEC		1000000
+#define ZDMA_DONE_TIMEOUT_USEC		5000000
+
+static void ecc_zdma_restore(void)
+{
+	/* Restore reset values for the DMA registers used */
+	writel(ZDMA_CH_CTRL0, 0x00000080U);
+	writel(ZDMA_CH_WR_ONLY_WORD0, 0x00000000U);
+	writel(ZDMA_CH_WR_ONLY_WORD1, 0x00000000U);
+	writel(ZDMA_CH_WR_ONLY_WORD2, 0x00000000U);
+	writel(ZDMA_CH_WR_ONLY_WORD3, 0x00000000U);
+	writel(ZDMA_CH_DST_DSCR_WORD0, 0x00000000U);
+	writel(ZDMA_CH_DST_DSCR_WORD1, 0x00000000U);
+	writel(ZDMA_CH_SRC_DSCR_WORD2, 0x00000000U);
+	writel(ZDMA_CH_DST_DSCR_WORD2, 0x00000000U);
+	writel(ZDMA_CH_CTRL0_TOTAL_BYTE_COUNT, 0x00000000U);
+}
+
+static void ecc_dram_bank_init(u64 addr, u64 len)
+{
+	bool retry = true;
+	u32 timeout;
+	u64 bytes;
+	u32 size;
+	u64 src;
+	u32 reg;
+
+	if (!len)
+		return;
+retry:
+	bytes = len;
+	src = addr;
+	ecc_zdma_restore();
+	while (bytes > 0) {
+		size = bytes > ZDMA_TRANSFER_MAX_LEN ?
+			ZDMA_TRANSFER_MAX_LEN : (u32)bytes;
+
+		/* Wait until the DMA is in idle state */
+		timeout = ZDMA_IDLE_TIMEOUT_USEC;
+		do {
+			udelay(1);
+			reg = readl(ZDMA_CH_STATUS);
+			reg &= ZDMA_CH_STATUS_STATE_MASK;
+			if (!timeout--) {
+				puts("error, ECC DMA failed to idle\n");
+				goto done;
+			}
+
+		} while ((reg != ZDMA_CH_STATUS_STATE_DONE) &&
+			(reg != ZDMA_CH_STATUS_STATE_ERR));
+
+		/* Enable Simple (Write Only) Mode */
+		reg = readl(ZDMA_CH_CTRL0);
+		reg &= (ZDMA_CH_CTRL0_POINT_TYPE_MASK |
+			ZDMA_CH_CTRL0_MODE_MASK);
+		reg |= (ZDMA_CH_CTRL0_POINT_TYPE_NORMAL |
+			ZDMA_CH_CTRL0_MODE_WR_ONLY);
+		writel(reg, ZDMA_CH_CTRL0);
+
+		/* Fill in the data to be written */
+		writel(ECC_INIT_VAL_WORD, ZDMA_CH_WR_ONLY_WORD0);
+		writel(ECC_INIT_VAL_WORD, ZDMA_CH_WR_ONLY_WORD1);
+		writel(ECC_INIT_VAL_WORD, ZDMA_CH_WR_ONLY_WORD2);
+		writel(ECC_INIT_VAL_WORD, ZDMA_CH_WR_ONLY_WORD3);
+
+		/* Write Destination Address */
+		writel((u32)(src & ZDMA_CH_DST_DSCR_WORD0_LSB_MASK),
+		       ZDMA_CH_DST_DSCR_WORD0);
+		writel((u32)((src >> 32) & ZDMA_CH_DST_DSCR_WORD1_MSB_MASK),
+		       ZDMA_CH_DST_DSCR_WORD1);
+
+		/* Size to be Transferred. Recommended to set both src and dest sizes */
+		writel(size, ZDMA_CH_SRC_DSCR_WORD2);
+		writel(size, ZDMA_CH_DST_DSCR_WORD2);
+
+		/* DMA Enable */
+		reg = readl(ZDMA_CH_CTRL2);
+		reg |= ZDMA_CH_CTRL2_EN_MASK;
+		writel(reg, ZDMA_CH_CTRL2);
+
+		/* Check the status of the transfer by polling on DMA Done */
+		timeout = ZDMA_DONE_TIMEOUT_USEC;
+		do {
+			udelay(1);
+			reg = readl(ZDMA_CH_ISR);
+			reg &= ZDMA_CH_ISR_DMA_DONE_MASK;
+			if (!timeout--) {
+				puts("error, ECC DMA timeout\n");
+				goto done;
+			}
+		} while (reg != ZDMA_CH_ISR_DMA_DONE_MASK);
+
+		/* Clear DMA status */
+		reg = readl(ZDMA_CH_ISR);
+		reg |= ZDMA_CH_ISR_DMA_DONE_MASK;
+		writel(ZDMA_CH_ISR_DMA_DONE_MASK, ZDMA_CH_ISR);
+
+		/* Read the channel status for errors */
+		reg = readl(ZDMA_CH_STATUS);
+		if (reg == ZDMA_CH_STATUS_STATE_ERR) {
+			if (retry) {
+				retry = false;
+				goto retry;
+			}
+			puts("error, ECC DMA error\n");
+			break;
+		}
+
+		bytes -= size;
+		src += size;
+	}
+done:
+	ecc_zdma_restore();
+}
+
+void zynqmp_ecc_init(void)
+{
+	ecc_dram_bank_init(CONFIG_SPL_ZYNQMP_DRAM_BANK1_BASE,
+			   CONFIG_SPL_ZYNQMP_DRAM_BANK1_LEN);
+	ecc_dram_bank_init(CONFIG_SPL_ZYNQMP_DRAM_BANK2_BASE,
+			   CONFIG_SPL_ZYNQMP_DRAM_BANK2_LEN);
+}

arch/arm/mach-zynqmp/include/mach/ecc_spl_init.h

@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ *  Copyright(c) 2015 - 2020 Xilinx, Inc.
+ *
+ *  Jorge Ramirez-Ortiz <jorge@foundries.io>
+ */
+
+#ifndef __ARCH_ZYNQMP_ECC_INIT_H
+#define __ARCH_ZYNQMP_ECC_INIT_H
+
+void zynqmp_ecc_init(void);
+
+#endif

arch/arm/mach-zynqmp/include/mach/hardware.h

@@ -24,6 +24,8 @@
 							    + 0x00000114)
 #define ZYNQMP_PS_SYSMON_ANALOG_BUS_VAL 0x00003210
 
+#define ADMA_CH0_BASEADDR	0xFFA80000
+
 #define PS_MODE0	BIT(0)
 #define PS_MODE1	BIT(1)
 #define PS_MODE2	BIT(2)

arch/arm/mach-zynqmp/spl.c

@@ -15,6 +15,7 @@
 #include <asm/io.h>
 #include <asm/spl.h>
 #include <asm/arch/hardware.h>
+#include <asm/arch/ecc_spl_init.h>
 #include <asm/arch/psu_init_gpl.h>
 #include <asm/arch/sys_proto.h>
 
@@ -22,6 +23,9 @@ void board_init_f(ulong dummy)
 {
 	board_early_init_f();
 	board_early_init_r();
+#ifdef CONFIG_SPL_ZYNQMP_DRAM_ECC_INIT
+	zynqmp_ecc_init();
+#endif
 }
 
 static void ps_mode_reset(ulong mode)