[PATCH] lib: utils: serial: Add Cadence UART driver
Jun Liang Tan
junliang.tan at linux.starfivetech.com
Thu Jul 7 22:50:05 PDT 2022
Add Cadence UART driver
Signed-off-by: Jun Liang Tan <junliang.tan at linux.starfivetech.com>
Signed-off-by: Wei Liang Lim <weiliang.lim at linux.starfivetech.com>
---
include/sbi_utils/fdt/fdt_helper.h | 3 +
include/sbi_utils/serial/cadence-uart.h | 16 +++
lib/utils/fdt/fdt_helper.c | 35 +++++++
lib/utils/serial/cadence-uart.c | 125 ++++++++++++++++++++++++
lib/utils/serial/fdt_serial.c | 2 +
lib/utils/serial/fdt_serial_cadence.c | 35 +++++++
lib/utils/serial/objects.mk | 2 +
7 files changed, 218 insertions(+)
create mode 100644 include/sbi_utils/serial/cadence-uart.h
create mode 100644 lib/utils/serial/cadence-uart.c
create mode 100644 lib/utils/serial/fdt_serial_cadence.c
diff --git a/include/sbi_utils/fdt/fdt_helper.h b/include/sbi_utils/fdt/fdt_helper.h
index 24fee7a..1166208 100644
--- a/include/sbi_utils/fdt/fdt_helper.h
+++ b/include/sbi_utils/fdt/fdt_helper.h
@@ -53,6 +53,9 @@ int fdt_parse_max_hart_id(void *fdt, u32 *max_hartid);
int fdt_parse_timebase_frequency(void *fdt, unsigned long *freq);
+int fdt_parse_cadence_uart_node(void *fdt, int nodeoffset,
+ struct platform_uart_data *uart);
+
int fdt_parse_gaisler_uart_node(void *fdt, int nodeoffset,
struct platform_uart_data *uart);
diff --git a/include/sbi_utils/serial/cadence-uart.h b/include/sbi_utils/serial/cadence-uart.h
new file mode 100644
index 0000000..e75fb95
--- /dev/null
+++ b/include/sbi_utils/serial/cadence-uart.h
@@ -0,0 +1,16 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2022 StarFive Technology Co., Ltd.
+ *
+ * Author: Jun Liang Tan <junliang.tan at linux.starfivetech.com>
+ */
+
+#ifndef __SERIAL_CADENCE_UART_H__
+#define __SERIAL_CADENCE_UART_H__
+
+#include <sbi/sbi_types.h>
+
+int cadence_uart_init(unsigned long base, u32 in_freq, u32 baudrate);
+
+#endif
diff --git a/lib/utils/fdt/fdt_helper.c b/lib/utils/fdt/fdt_helper.c
index 5bf4021..3ad0a5e 100644
--- a/lib/utils/fdt/fdt_helper.c
+++ b/lib/utils/fdt/fdt_helper.c
@@ -290,6 +290,41 @@ int fdt_parse_timebase_frequency(void *fdt, unsigned long *freq)
return 0;
}
+int fdt_parse_cadence_uart_node(void *fdt, int nodeoffset,
+ struct platform_uart_data *uart)
+{
+ int len, rc;
+ const fdt32_t *val;
+ u64 reg_addr, reg_size;
+
+ if (nodeoffset < 0 || !uart || !fdt)
+ return SBI_ENODEV;
+
+ rc = fdt_get_node_addr_size(fdt, nodeoffset, 0,
+ ®_addr, ®_size);
+ if (rc < 0 || !reg_addr || !reg_size)
+ return SBI_ENODEV;
+ uart->addr = reg_addr;
+
+ /**
+ * UART address is mandatory. clock-frequency and current-speed
+ * may not be present. Don't return error.
+ */
+ val = (fdt32_t *)fdt_getprop(fdt, nodeoffset, "clock-frequency", &len);
+ if (len > 0 && val)
+ uart->freq = fdt32_to_cpu(*val);
+ else
+ uart->freq = DEFAULT_UART_FREQ;
+
+ val = (fdt32_t *)fdt_getprop(fdt, nodeoffset, "current-speed", &len);
+ if (len > 0 && val)
+ uart->baud = fdt32_to_cpu(*val);
+ else
+ uart->baud = DEFAULT_UART_BAUD;
+
+ return 0;
+}
+
int fdt_parse_gaisler_uart_node(void *fdt, int nodeoffset,
struct platform_uart_data *uart)
{
diff --git a/lib/utils/serial/cadence-uart.c b/lib/utils/serial/cadence-uart.c
new file mode 100644
index 0000000..ffa79f8
--- /dev/null
+++ b/lib/utils/serial/cadence-uart.c
@@ -0,0 +1,125 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2022 StarFive Technology Co., Ltd.
+ *
+ * Author: Jun Liang Tan <junliang.tan at linux.starfivetech.com>
+ */
+
+#include <sbi/riscv_io.h>
+#include <sbi/sbi_console.h>
+#include <sbi_utils/serial/cadence-uart.h>
+
+/* clang-format off */
+
+#define UART_REG_OFFSET_CTRL 0x00 /* Control register */
+#define UART_REG_OFFSET_MODE 0x04 /* Mode register */
+#define UART_REG_OFFSET_CH_STS 0x2C /* Channel status register */
+#define UART_REG_OFFSET_RX_TX_FIFO 0x30 /* RX and TX FIFO register */
+#define UART_REG_OFFSET_INT_DIS 0x0C /* Interrupt disable register */
+#define UART_REG_OFFSET_BRG 0x18 /* Baud rate generator register */
+#define UART_REG_OFFSET_BRD 0x34 /* Baud rate divider register */
+
+/* Control register, 0x00 */
+#define UART_CR_TX_DIS 0x00000020 /* TX disabled, bit 5 */
+#define UART_CR_TX_EN 0x00000010 /* TX enabled, bit 4 */
+#define UART_CR_RX_DIS 0x00000008 /* RX disabled, bit 3 */
+#define UART_CR_RX_EN 0x00000004 /* RX enabled, bit 2*/
+#define UART_CR_TXRST 0x00000002 /* TX logic reset, bit 1 */
+#define UART_CR_RXRST 0x00000001 /* RX logic reset, bit 0 */
+
+/* Channel status register, 0x2C */
+#define UART_CHSR_TXFULL 0x00000010 /* TX FIFO full, bit 4 */
+#define UART_CHSR_RXEMPTY 0x00000002 /* RX FIFO empty, bit 1 */
+
+/* Mode register, 0x04 */
+#define UART_MR_PARITY_NONE 0x00000020 /* No parity set */
+
+/* Baud rate generator register, 0x18 */
+#define UART_BRG_CLK_DIVISOR 0x00000001 /* baud_sample = sel_clk */
+
+/* clang-format on */
+
+static volatile void *uart_base;
+static u32 uart_in_freq;
+static u32 uart_baudrate;
+
+/**
+ * Find minimum divisor divides in_freq to max_target_hz;
+ * Based on SiFive UART driver (sifive-uart.c)
+ */
+static inline unsigned int uart_min_clk_divisor(uint64_t in_freq,
+ uint64_t max_target_hz)
+{
+ uint64_t quotient = (in_freq + max_target_hz - 1) / (max_target_hz);
+ /* Avoid underflow */
+ if (quotient == 0)
+ return 0;
+ else
+ return quotient - 1;
+}
+
+static u32 get_reg(u32 offset)
+{
+ return readl(uart_base + offset);
+}
+
+static void set_reg(u32 offset, u32 val)
+{
+ writel(val, uart_base + offset);
+}
+
+static void cadence_uart_putc(char ch)
+{
+ while (get_reg(UART_REG_OFFSET_CH_STS) & UART_CHSR_TXFULL)
+ ;
+
+ set_reg(UART_REG_OFFSET_RX_TX_FIFO, ch);
+}
+
+static int cadence_uart_getc(void)
+{
+ u32 ret = get_reg(UART_REG_OFFSET_CH_STS);
+
+ if (!(ret & UART_CHSR_RXEMPTY))
+ return get_reg(UART_REG_OFFSET_RX_TX_FIFO);
+ return -1;
+}
+
+static struct sbi_console_device cadence_console = {
+ .name = "cadence_uart",
+ .console_putc = cadence_uart_putc,
+ .console_getc = cadence_uart_getc
+};
+
+int cadence_uart_init(unsigned long base, u32 in_freq, u32 baudrate)
+{
+ uart_base = (volatile void *)base;
+ uart_in_freq = in_freq;
+ uart_baudrate = baudrate;
+
+ /* Disable interrupts */
+ set_reg(UART_REG_OFFSET_INT_DIS, 0xFFFFFFFF);
+ /* Disable TX RX */
+ set_reg(UART_REG_OFFSET_CTRL, UART_CR_TX_DIS | UART_CR_RX_DIS);
+ /* Configure baudrate */
+ if (in_freq) {
+ set_reg(UART_REG_OFFSET_BRG, UART_BRG_CLK_DIVISOR);
+ set_reg(UART_REG_OFFSET_BRD,
+ uart_min_clk_divisor(in_freq, baudrate));
+ }
+ /* Software reset TX RX data path and enable TX RX */
+ set_reg(UART_REG_OFFSET_CTRL, UART_CR_TXRST | UART_CR_RXRST
+ | UART_CR_TX_EN | UART_CR_RX_EN);
+ /* Set:
+ * 1 stop bit, bits[07:06] = 0x00,
+ * no parity set, bits[05:03] = 0x100,
+ * 8 bits character length, bits[02:01] = 0x00,
+ * sel_clk = uart_clk, bit[0] = 0x0
+ */
+ set_reg(UART_REG_OFFSET_MODE, UART_MR_PARITY_NONE);
+
+ sbi_console_set_device(&cadence_console);
+
+ return 0;
+}
diff --git a/lib/utils/serial/fdt_serial.c b/lib/utils/serial/fdt_serial.c
index f73d26a..460f516 100644
--- a/lib/utils/serial/fdt_serial.c
+++ b/lib/utils/serial/fdt_serial.c
@@ -13,6 +13,7 @@
#include <sbi_utils/fdt/fdt_helper.h>
#include <sbi_utils/serial/fdt_serial.h>
+extern struct fdt_serial fdt_serial_cadence;
extern struct fdt_serial fdt_serial_uart8250;
extern struct fdt_serial fdt_serial_sifive;
extern struct fdt_serial fdt_serial_litex;
@@ -21,6 +22,7 @@ extern struct fdt_serial fdt_serial_shakti;
extern struct fdt_serial fdt_serial_gaisler;
static struct fdt_serial *serial_drivers[] = {
+ &fdt_serial_cadence,
&fdt_serial_uart8250,
&fdt_serial_sifive,
&fdt_serial_litex,
diff --git a/lib/utils/serial/fdt_serial_cadence.c b/lib/utils/serial/fdt_serial_cadence.c
new file mode 100644
index 0000000..f6f13d6
--- /dev/null
+++ b/lib/utils/serial/fdt_serial_cadence.c
@@ -0,0 +1,35 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2022 StarFive Technology Co., Ltd.
+ *
+ * Author: Jun Liang Tan <junliang.tan at linux.starfivetech.com>
+ */
+
+#include <sbi_utils/fdt/fdt_helper.h>
+#include <sbi_utils/serial/fdt_serial.h>
+#include <sbi_utils/serial/cadence-uart.h>
+
+static int serial_cadence_init(void *fdt, int nodeoff,
+ const struct fdt_match *match)
+{
+ int rc;
+ struct platform_uart_data uart;
+
+ rc = fdt_parse_cadence_uart_node(fdt, nodeoff, &uart);
+ if (rc)
+ return rc;
+
+ return cadence_uart_init(uart.addr, uart.freq, uart.baud);
+}
+
+static const struct fdt_match serial_cadence_match[] = {
+ { .compatible = "cdns,uart-r1p12" },
+ { .compatible = "starfive,jh8100-uart" },
+ { },
+};
+
+struct fdt_serial fdt_serial_cadence = {
+ .match_table = serial_cadence_match,
+ .init = serial_cadence_init
+};
diff --git a/lib/utils/serial/objects.mk b/lib/utils/serial/objects.mk
index 4f751ba..c201d76 100644
--- a/lib/utils/serial/objects.mk
+++ b/lib/utils/serial/objects.mk
@@ -8,12 +8,14 @@
#
libsbiutils-objs-y += serial/fdt_serial.o
+libsbiutils-objs-y += serial/fdt_serial_cadence.o
libsbiutils-objs-y += serial/fdt_serial_gaisler.o
libsbiutils-objs-y += serial/fdt_serial_htif.o
libsbiutils-objs-y += serial/fdt_serial_shakti.o
libsbiutils-objs-y += serial/fdt_serial_sifive.o
libsbiutils-objs-y += serial/fdt_serial_litex.o
libsbiutils-objs-y += serial/fdt_serial_uart8250.o
+libsbiutils-objs-y += serial/cadence-uart.o
libsbiutils-objs-y += serial/gaisler-uart.o
libsbiutils-objs-y += serial/shakti-uart.o
libsbiutils-objs-y += serial/sifive-uart.o
--
2.25.1
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