feat(msm8916): add SP_MIN port for AArch32
Use the new shared msm8916 setup code to allow compiling the minimal
AArch32 Secure Payload (SP_MIN) as simple PSCI implementation.
AArch64 is preferred for the Cortex-A53 cores in MSM8916 but there are
some similar platforms with AArch32-only Cortex-A7 cores that can
benefit from this in future changes.
The AArch32 assembly implementation for msm8916_helpers.S and
uartdm_console.S is a direct port of the AArch64 implementation.
Only plat_get_my_entrypoint is slightly different because there is no
need to handle the "boot remapper" on cold boot for AArch32.
Change-Id: Idf160e86fb3e685fcedec3e051400e6273997b74
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
diff --git a/plat/qti/msm8916/aarch32/uartdm_console.S b/plat/qti/msm8916/aarch32/uartdm_console.S
new file mode 100644
index 0000000..a19776a
--- /dev/null
+++ b/plat/qti/msm8916/aarch32/uartdm_console.S
@@ -0,0 +1,183 @@
+/*
+ * Copyright (c) 2021-2023, Stephan Gerhold <stephan@gerhold.net>
+ *
+ * Based on aarch32/skeleton_console.S:
+ * Copyright (c) 2016-2020, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <asm_macros.S>
+#include <console_macros.S>
+
+/* UART DM registers */
+#define UART_DM_DMEN 0x03c /* DMA / data packing */
+#define UART_DM_SR 0x0a4 /* status register */
+#define UART_DM_CR 0x0a8 /* command register */
+#define UART_DM_TF 0x100 /* transmit FIFO */
+
+#define UART_DM_DMEN_TX_SC BIT_32(4) /* TX single character mode */
+
+#define UART_DM_SR_TXRDY BIT_32(2) /* TX FIFO has space */
+#define UART_DM_SR_TXEMT BIT_32(3) /* TX FIFO is empty */
+
+#define UART_DM_CR_RESET_RX (U(0x01) << 4) /* reset receiver */
+#define UART_DM_CR_RESET_TX (U(0x02) << 4) /* reset transmitter */
+#define UART_DM_CR_TX_ENABLE BIT_32(2) /* enable transmitter */
+
+ .globl console_uartdm_register
+ .globl console_uartdm_core_init
+ .globl console_uartdm_putc
+ .globl console_uartdm_core_putc
+ .globl console_uartdm_flush
+ .globl console_uartdm_core_flush
+
+ /* -----------------------------------------------------------
+ * int console_uartdm_register(console_t *console,
+ * uintptr_t base_addr)
+ * Function to initialize and register the console. The caller
+ * needs to pass an empty console_t structure in which *MUST*
+ * be allocated in persistent memory (e.g. a global or static
+ * local variable, *NOT* on the stack).
+ * In : r0 - pointer to empty console_t structure
+ * r1 - base address
+ * Out: r0 - 1 on success, 0 on error
+ * Clobber list : r0 - r7
+ * -----------------------------------------------------------
+ */
+func console_uartdm_register
+ str r1, [r0, #CONSOLE_T_BASE]
+ mov r7, lr
+ bl console_uartdm_core_init
+ mov lr, r7
+
+ /* Register the new console */
+ finish_console_register uartdm putc=1, flush=1
+endfunc console_uartdm_register
+
+ /* -----------------------------------------------------------
+ * void console_uartdm_core_init(unused, uintptr_t base_addr)
+ * Function to initialize the console.
+ * In : r0 - unused
+ * r1 - base address
+ * Out: void
+ * Clobber list : r1, r2, r3
+ * -----------------------------------------------------------
+ */
+func console_uartdm_core_init
+ /*
+ * Try to flush remaining characters from the TX FIFO before resetting
+ * the transmitter. Unfortunately there is no good way to check if
+ * the transmitter is actually enabled (and will finish eventually),
+ * so use a timeout to avoid looping forever.
+ */
+ mov r2, #65536
+1:
+ ldr r3, [r1, #UART_DM_SR]
+ tst r3, #UART_DM_SR_TXEMT
+ bne 2f
+ subs r2, r2, #1
+ bne 1b
+ /* Timeout */
+
+2: /* Reset receiver */
+ mov r3, #UART_DM_CR_RESET_RX
+ str r3, [r1, #UART_DM_CR]
+
+ /* Reset transmitter */
+ mov r3, #UART_DM_CR_RESET_TX
+ str r3, [r1, #UART_DM_CR]
+
+ /*
+ * Disable BAM/DMA modes but enable single-character mode for TX.
+ * The single character mode allows simplifying the putc implementation
+ * since characters can be written directly to the FIFO instead of
+ * having to initiate a new transfer and waiting for its completion.
+ */
+ mov r3, #UART_DM_DMEN_TX_SC
+ str r3, [r1, #UART_DM_DMEN]
+
+ /* Enable transmitter */
+ mov r3, #UART_DM_CR_TX_ENABLE
+ str r3, [r1, #UART_DM_CR]
+
+ bx lr
+endfunc console_uartdm_core_init
+
+ /* -----------------------------------------------------------
+ * int console_uartdm_putc(int c, console_t *console)
+ * Function to output a character over the console.
+ * In : r0 - character to be printed
+ * r1 - pointer to console_t struct
+ * Out: r0 - printed character on success, < 0 on error.
+ * Clobber list : r0, r1, r2
+ * -----------------------------------------------------------
+ */
+func console_uartdm_putc
+ ldr r1, [r1, #CONSOLE_T_BASE]
+ b console_uartdm_core_putc
+endfunc console_uartdm_putc
+
+ /* -----------------------------------------------------------
+ * int console_uartdm_core_putc(int c, uintptr_t base_addr)
+ * Function to output a character over the console.
+ * In : r0 - character to be printed
+ * r1 - base address
+ * Out: r0 - printed character on success, < 0 on error.
+ * Clobber list : r2
+ * -----------------------------------------------------------
+ */
+func console_uartdm_core_putc
+ cmp r0, #'\n'
+ bne 2f
+
+1: /* Loop until TX FIFO has space */
+ ldr r2, [r1, #UART_DM_SR]
+ tst r2, #UART_DM_SR_TXRDY
+ beq 1b
+
+ /* Prepend '\r' to '\n' */
+ mov r2, #'\r'
+ str r2, [r1, #UART_DM_TF]
+
+2: /* Loop until TX FIFO has space */
+ ldr r2, [r1, #UART_DM_SR]
+ tst r2, #UART_DM_SR_TXRDY
+ beq 2b
+
+ /* Write character to FIFO */
+ str r0, [r1, #UART_DM_TF]
+ bx lr
+endfunc console_uartdm_core_putc
+
+ /* -----------------------------------------------------------
+ * void console_uartdm_flush(console_t *console)
+ * Function to force a write of all buffered data
+ * that has not been output.
+ * In : r0 - pointer to console_t struct
+ * Out: void
+ * Clobber list : r0, r1, r2, r3, r4, r5
+ * -----------------------------------------------------------
+ */
+func console_uartdm_flush
+ ldr r1, [r0, #CONSOLE_T_BASE]
+ b console_uartdm_core_flush
+endfunc console_uartdm_flush
+
+ /* -----------------------------------------------------------
+ * void console_uartdm_core_flush(unused, uintptr_t base_addr)
+ * Function to force a write of all buffered data
+ * that has not been output.
+ * In : r0 - unused
+ * r1 - base address
+ * Out: void
+ * Clobber list : r2
+ * -----------------------------------------------------------
+ */
+func console_uartdm_core_flush
+1: /* Loop until TX FIFO is empty */
+ ldr r2, [r1, #UART_DM_SR]
+ tst r2, #UART_DM_SR_TXEMT
+ beq 1b
+ bx lr
+endfunc console_uartdm_core_flush