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-rw-r--r--arch/mips/ath79/early_printk.c144
1 files changed, 144 insertions, 0 deletions
diff --git a/arch/mips/ath79/early_printk.c b/arch/mips/ath79/early_printk.c
new file mode 100644
index 000000000..34c4dfdf4
--- /dev/null
+++ b/arch/mips/ath79/early_printk.c
@@ -0,0 +1,144 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Atheros AR7XXX/AR9XXX SoC early printk support
+ *
+ * Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
+ * Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
+ */
+
+#include <linux/io.h>
+#include <linux/errno.h>
+#include <linux/serial.h>
+#include <linux/serial_reg.h>
+#include <asm/addrspace.h>
+#include <asm/setup.h>
+
+#include <asm/mach-ath79/ath79.h>
+#include <asm/mach-ath79/ar71xx_regs.h>
+#include <asm/mach-ath79/ar933x_uart.h>
+
+static void (*_prom_putchar)(char);
+
+static inline void prom_putchar_wait(void __iomem *reg, u32 val)
+{
+ u32 t;
+
+ do {
+ t = __raw_readl(reg);
+ if ((t & val) == val)
+ break;
+ } while (1);
+}
+
+static void prom_putchar_ar71xx(char ch)
+{
+ void __iomem *base = (void __iomem *)(KSEG1ADDR(AR71XX_UART_BASE));
+
+ prom_putchar_wait(base + UART_LSR * 4, UART_LSR_BOTH_EMPTY);
+ __raw_writel((unsigned char)ch, base + UART_TX * 4);
+ prom_putchar_wait(base + UART_LSR * 4, UART_LSR_BOTH_EMPTY);
+}
+
+static void prom_putchar_ar933x(char ch)
+{
+ void __iomem *base = (void __iomem *)(KSEG1ADDR(AR933X_UART_BASE));
+
+ prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR);
+ __raw_writel(AR933X_UART_DATA_TX_CSR | (unsigned char)ch,
+ base + AR933X_UART_DATA_REG);
+ prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR);
+}
+
+static void prom_putchar_dummy(char ch)
+{
+ /* nothing to do */
+}
+
+static void prom_enable_uart(u32 id)
+{
+ void __iomem *gpio_base;
+ u32 uart_en;
+ u32 t;
+
+ switch (id) {
+ case REV_ID_MAJOR_AR71XX:
+ uart_en = AR71XX_GPIO_FUNC_UART_EN;
+ break;
+
+ case REV_ID_MAJOR_AR7240:
+ case REV_ID_MAJOR_AR7241:
+ case REV_ID_MAJOR_AR7242:
+ uart_en = AR724X_GPIO_FUNC_UART_EN;
+ break;
+
+ case REV_ID_MAJOR_AR913X:
+ uart_en = AR913X_GPIO_FUNC_UART_EN;
+ break;
+
+ case REV_ID_MAJOR_AR9330:
+ case REV_ID_MAJOR_AR9331:
+ uart_en = AR933X_GPIO_FUNC_UART_EN;
+ break;
+
+ case REV_ID_MAJOR_AR9341:
+ case REV_ID_MAJOR_AR9342:
+ case REV_ID_MAJOR_AR9344:
+ /* TODO */
+ default:
+ return;
+ }
+
+ gpio_base = (void __iomem *)KSEG1ADDR(AR71XX_GPIO_BASE);
+ t = __raw_readl(gpio_base + AR71XX_GPIO_REG_FUNC);
+ t |= uart_en;
+ __raw_writel(t, gpio_base + AR71XX_GPIO_REG_FUNC);
+}
+
+static void prom_putchar_init(void)
+{
+ void __iomem *base;
+ u32 id;
+
+ base = (void __iomem *)(KSEG1ADDR(AR71XX_RESET_BASE));
+ id = __raw_readl(base + AR71XX_RESET_REG_REV_ID);
+ id &= REV_ID_MAJOR_MASK;
+
+ switch (id) {
+ case REV_ID_MAJOR_AR71XX:
+ case REV_ID_MAJOR_AR7240:
+ case REV_ID_MAJOR_AR7241:
+ case REV_ID_MAJOR_AR7242:
+ case REV_ID_MAJOR_AR913X:
+ case REV_ID_MAJOR_AR9341:
+ case REV_ID_MAJOR_AR9342:
+ case REV_ID_MAJOR_AR9344:
+ case REV_ID_MAJOR_QCA9533:
+ case REV_ID_MAJOR_QCA9533_V2:
+ case REV_ID_MAJOR_QCA9556:
+ case REV_ID_MAJOR_QCA9558:
+ case REV_ID_MAJOR_TP9343:
+ case REV_ID_MAJOR_QCA956X:
+ case REV_ID_MAJOR_QCN550X:
+ _prom_putchar = prom_putchar_ar71xx;
+ break;
+
+ case REV_ID_MAJOR_AR9330:
+ case REV_ID_MAJOR_AR9331:
+ _prom_putchar = prom_putchar_ar933x;
+ break;
+
+ default:
+ _prom_putchar = prom_putchar_dummy;
+ return;
+ }
+
+ prom_enable_uart(id);
+}
+
+void prom_putchar(char ch)
+{
+ if (!_prom_putchar)
+ prom_putchar_init();
+
+ _prom_putchar(ch);
+}