1 files changed, 184 insertions, 0 deletions
diff --git a/arch/arm/boards/nxp-imx8mm-evk/lowlevel.c b/arch/arm/boards/nxp-imx8mm-evk/lowlevel.c
new file mode 100644
index 0000000000..cd1f7d168b
--- /dev/null
+++ b/arch/arm/boards/nxp-imx8mm-evk/lowlevel.c
@@ -0,0 +1,184 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <io.h>
+#include <common.h>
+#include <debug_ll.h>
+#include <firmware.h>
+#include <asm/mmu.h>
+#include <asm/cache.h>
+#include <asm/sections.h>
+#include <asm/barebox-arm.h>
+#include <asm/barebox-arm-head.h>
+#include <i2c/i2c-early.h>
+#include <linux/sizes.h>
+#include <mach/atf.h>
+#include <mach/xload.h>
+#include <mach/esdctl.h>
+#include <mach/generic.h>
+#include <mach/imx8mm-regs.h>
+#include <mach/iomux-mx8mm.h>
+#include <mach/imx8m-ccm-regs.h>
+#include <mfd/bd71837.h>
+#include <soc/imx8m/ddr.h>
+#include <soc/fsl/fsl_udc.h>
+
+extern char __dtb_imx8mm_evk_start[];
+
+#define UART_PAD_CTRL	MUX_PAD_CTRL(PAD_CTL_DSE_3P3V_45_OHM)
+
+static void setup_uart(void)
+{
+	imx8m_early_setup_uart_clock();
+
+	imx8mm_setup_pad(IMX8MM_PAD_UART2_TXD_UART2_TX | UART_PAD_CTRL);
+
+	imx8m_uart_setup_ll();
+
+	putc_ll('>');
+}
+
+static void pmic_reg_write(void *i2c, int reg, uint8_t val)
+{
+	int ret;
+	u8 buf[32];
+	struct i2c_msg msgs[] = {
+		{
+			.addr = 0x4b,
+			.buf = buf,
+		},
+	};
+
+	buf[0] = reg;
+	buf[1] = val;
+
+	msgs[0].len = 2;
+
+	ret = i2c_fsl_xfer(i2c, msgs, ARRAY_SIZE(msgs));
+	if (ret != 1)
+		pr_err("Failed to write to pmic\n");
+}
+
+static int power_init_board(void)
+{
+	void *i2c;
+
+	imx8mm_setup_pad(IMX8MM_PAD_I2C1_SCL_I2C1_SCL);
+	imx8mm_setup_pad(IMX8MM_PAD_I2C1_SDA_I2C1_SDA);
+
+	imx8mm_early_clock_init();
+	imx8m_ccgr_clock_enable(IMX8M_CCM_CCGR_I2C1);
+
+	i2c = imx8m_i2c_early_init(IOMEM(MX8MQ_I2C1_BASE_ADDR));
+
+	/* decrease RESET key long push time from the default 10s to 10ms */
+	pmic_reg_write(i2c, BD718XX_PWRONCONFIG1, 0x0);
+
+	/* unlock the PMIC regs */
+	pmic_reg_write(i2c, BD718XX_REGLOCK, 0x1);
+
+	/* increase VDD_SOC to typical value 0.85v before first DRAM access */
+	pmic_reg_write(i2c, BD718XX_BUCK1_VOLT_RUN, 0x0f);
+
+	/* increase VDD_DRAM to 0.975v for 3Ghz DDR */
+	pmic_reg_write(i2c, BD718XX_1ST_NODVS_BUCK_VOLT, 0x83);
+
+	/* lock the PMIC regs */
+	pmic_reg_write(i2c, BD718XX_REGLOCK, 0x11);
+
+	return 0;
+}
+
+extern struct dram_timing_info imx8mm_evk_dram_timing;
+
+static void start_atf(void)
+{
+	size_t bl31_size;
+	const u8 *bl31;
+	enum bootsource src;
+	int instance;
+
+	/*
+	 * If we are in EL3 we are running for the first time and need to
+	 * initialize the DRAM and run TF-A (BL31). The TF-A will then jump
+	 * to DRAM in EL2.
+	 */
+	if (current_el() != 3)
+		return;
+
+	power_init_board();
+	imx8mm_ddr_init(&imx8mm_evk_dram_timing);
+
+	imx8mm_get_boot_source(&src, &instance);
+	switch (src) {
+	case BOOTSOURCE_MMC:
+		imx8m_esdhc_load_image(instance, false);
+		break;
+	case BOOTSOURCE_SERIAL:
+		imx8mm_barebox_load_usb((void *)MX8M_ATF_BL33_BASE_ADDR);
+	break;
+	default:
+		printf("Unhandled bootsource BOOTSOURCE_%d\n", src);
+		hang();
+	}
+
+	/*
+	 * On completion the TF-A will jump to MX8M_ATF_BL33_BASE_ADDR
+	 * in EL2. Copy the image there, but replace the PBL part of
+	 * that image with ourselves. On a high assurance boot only the
+	 * currently running code is validated and contains the checksum
+	 * for the piggy data, so we need to ensure that we are running
+	 * the same code in DRAM.
+	 */
+	memcpy((void *)MX8M_ATF_BL33_BASE_ADDR,
+	       __image_start, barebox_pbl_size);
+
+	get_builtin_firmware(imx8mm_bl31_bin, &bl31, &bl31_size);
+
+	imx8mm_atf_load_bl31(bl31, bl31_size);
+
+	/* not reached */
+}
+
+/*
+ * Power-on execution flow of start_nxp_imx8mm_evk() might not be
+ * obvious for a very first read, so here's, hopefully helpful,
+ * summary:
+ *
+ * 1. MaskROM uploads PBL into OCRAM and that's where this function is
+ *    executed for the first time. At entry the exception level is EL3.
+ *
+ * 2. DDR is initialized and the image is loaded from storage into DRAM. The PBL
+ *    part is copied from OCRAM to the TF-A return address in DRAM.
+ *
+ * 3. TF-A is executed and exits into the PBL code in DRAM. TF-A has taken us
+ *    from EL3 to EL2.
+ *
+ * 4. Standard barebox boot flow continues
+ */
+static __noreturn noinline void nxp_imx8mm_evk_start(void)
+{
+	if (IS_ENABLED(CONFIG_DEBUG_LL))
+		setup_uart();
+
+	start_atf();
+
+	/*
+	 * Standard entry we hit once we initialized both DDR and ATF
+	 */
+	imx8mm_barebox_entry(__dtb_imx8mm_evk_start);
+}
+
+ENTRY_FUNCTION(start_nxp_imx8mm_evk, r0, r1, r2)
+{
+	void __iomem *ccm = IOMEM(MX8M_CCM_BASE_ADDR);
+
+	writel(IMX8M_CCM_CCGR_SETTINGn_NEEDED(0),
+	       ccm + IMX8M_CCM_CCGRn_SET(IMX8M_CCM_CCGR_SCTR));
+
+	imx8mm_cpu_lowlevel_init();
+
+	relocate_to_current_adr();
+	setup_c();
+
+	nxp_imx8mm_evk_start();
+}