1 /* 2 * Copyright (c) 2023, Pengutronix. All rights reserved. 3 * 4 * SPDX-License-Identifier: BSD-3-Clause 5 */ 6 7 #include <lib/mmio.h> 8 #include <platform_def.h> 9 10 #define UCR1 0x80 11 #define UCR1_UARTEN BIT(0) 12 #define DOMAIN0_RUNNING(d) (((d) & 0x3) != 0) 13 14 static struct imx_uart { 15 unsigned int ccm_reg; 16 unsigned int uart_base; 17 } imx8m_uart_info[] = { 18 { /* UART 1 */ 19 .ccm_reg = 0x4490, 20 .uart_base = 0x30860000, 21 }, { /* UART 2 */ 22 .ccm_reg = 0x44a0, 23 .uart_base = 0x30890000, 24 }, { /* UART 3 */ 25 .ccm_reg = 0x44b0, 26 .uart_base = 0x30880000, 27 }, { /* UART 4 */ 28 .ccm_reg = 0x44c0, 29 .uart_base = 0x30a60000, 30 } 31 }; 32 33 unsigned int imx8m_uart_get_base(void) 34 { 35 unsigned int i; 36 37 for (i = 0; i < ARRAY_SIZE(imx8m_uart_info); i++) { 38 uint32_t val; 39 40 /* 41 * At least check that the clock-gate is ungated before we 42 * access the UART register. 43 */ 44 val = mmio_read_32(IMX_CCM_BASE + imx8m_uart_info[i].ccm_reg); 45 if (DOMAIN0_RUNNING(val)) { 46 val = mmio_read_32(imx8m_uart_info[i].uart_base + UCR1); 47 if (val & UCR1_UARTEN) { 48 return imx8m_uart_info[i].uart_base; 49 } 50 } 51 } 52 53 /* 54 * We should return an error and inform the user but we can't do it 55 * this early. 56 */ 57 return 0; 58 } 59