[PATCH v4] lib: utils: serial: Add Cadence UART driver
Jun Liang Tan
junliang.tan at linux.starfivetech.com
Wed Aug 17 08:40:56 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>
---
Changes in v4:
- Add changelog
- Check for possible divide-by-zero in uart_min_clk_divisor() by
referring to the fix in commit f27203525aa2fc20d0074feb892a6f8433f84e3a
- Cosmetic changes
Changes in v3:
- Place #define register name in ascending order of register offset
- Change #define register name to match manual register name
- #define register flags in a way associate with their register
- Cosmetic changes
Changes in v2:
- Rename fdt_parse_uart8250_node() to fdt_parse_uart_node() and make
neccessary changes in functions that call it
- Align patch with the latest OpenSBI sources
include/sbi_utils/fdt/fdt_helper.h | 4 +-
include/sbi_utils/serial/cadence-uart.h | 16 +++
lib/utils/fdt/fdt_helper.c | 6 +-
lib/utils/serial/Kconfig | 9 ++
lib/utils/serial/cadence-uart.c | 128 ++++++++++++++++++++++++
lib/utils/serial/fdt_serial_cadence.c | 35 +++++++
lib/utils/serial/fdt_serial_uart8250.c | 2 +-
lib/utils/serial/objects.mk | 4 +
platform/generic/configs/defconfig | 1 +
9 files changed, 199 insertions(+), 6 deletions(-)
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 c60af35..bcd4996 100644
--- a/include/sbi_utils/fdt/fdt_helper.h
+++ b/include/sbi_utils/fdt/fdt_helper.h
@@ -65,8 +65,8 @@ int fdt_parse_shakti_uart_node(void *fdt, int nodeoffset,
int fdt_parse_sifive_uart_node(void *fdt, int nodeoffset,
struct platform_uart_data *uart);
-int fdt_parse_uart8250_node(void *fdt, int nodeoffset,
- struct platform_uart_data *uart);
+int fdt_parse_uart_node(void *fdt, int nodeoffset,
+ struct platform_uart_data *uart);
int fdt_parse_uart8250(void *fdt, struct platform_uart_data *uart,
const char *compatible);
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 c6abf80..6a75d6f 100644
--- a/lib/utils/fdt/fdt_helper.c
+++ b/lib/utils/fdt/fdt_helper.c
@@ -401,8 +401,8 @@ int fdt_parse_sifive_uart_node(void *fdt, int nodeoffset,
return 0;
}
-int fdt_parse_uart8250_node(void *fdt, int nodeoffset,
- struct platform_uart_data *uart)
+int fdt_parse_uart_node(void *fdt, int nodeoffset,
+ struct platform_uart_data *uart)
{
int len, rc;
const fdt32_t *val;
@@ -447,7 +447,7 @@ int fdt_parse_uart8250(void *fdt, struct platform_uart_data *uart,
if (nodeoffset < 0)
return nodeoffset;
- return fdt_parse_uart8250_node(fdt, nodeoffset, uart);
+ return fdt_parse_uart_node(fdt, nodeoffset, uart);
}
int fdt_parse_xlnx_uartlite_node(void *fdt, int nodeoffset,
diff --git a/lib/utils/serial/Kconfig b/lib/utils/serial/Kconfig
index 152060d..6e425f2 100644
--- a/lib/utils/serial/Kconfig
+++ b/lib/utils/serial/Kconfig
@@ -9,6 +9,11 @@ config FDT_SERIAL
if FDT_SERIAL
+config FDT_SERIAL_CADENCE
+ bool "Cadence UART FDT driver"
+ select SERIAL_CADENCE
+ default n
+
config FDT_SERIAL_GAISLER
bool "Gaisler UART FDT driver"
select SERIAL_GAISLER
@@ -46,6 +51,10 @@ config FDT_SERIAL_XILINX_UARTLITE
endif
+config SERIAL_CADENCE
+ bool "Cadence UART support"
+ default n
+
config SERIAL_GAISLER
bool "Gaisler UART support"
default n
diff --git a/lib/utils/serial/cadence-uart.c b/lib/utils/serial/cadence-uart.c
new file mode 100644
index 0000000..8a2b6ba
--- /dev/null
+++ b/lib/utils/serial/cadence-uart.c
@@ -0,0 +1,128 @@
+/*
+ * 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_CTRL 0x00
+#define UART_REG_MODE 0x04
+#define UART_REG_IDR 0x0C
+#define UART_REG_BRGR 0x18
+#define UART_REG_CSR 0x2C
+#define UART_REG_RFIFO_TFIFO 0x30
+#define UART_REG_BDIVR 0x34
+
+#define UART_CTRL_RXRES 0x00000001
+#define UART_CTRL_TXRES 0x00000002
+#define UART_CTRL_RXEN 0x00000004
+#define UART_CTRL_RXDIS 0x00000008
+#define UART_CTRL_TXEN 0x00000010
+#define UART_CTRL_TXDIS 0x00000020
+
+#define UART_MODE_PAR_NONE 0x00000020 /* No parity set */
+
+#define UART_BRGR_CD_CLKDIVISOR 0x00000001 /* baud_sample = sel_clk */
+
+#define UART_CSR_REMPTY 0x00000002
+#define UART_CSR_TFUL 0x00000010
+
+/* 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_CSR) & UART_CSR_TFUL)
+ ;
+
+ set_reg(UART_REG_RFIFO_TFIFO, ch);
+}
+
+static int cadence_uart_getc(void)
+{
+ u32 ret = get_reg(UART_REG_CSR);
+
+ if (!(ret & UART_CSR_REMPTY))
+ return get_reg(UART_REG_RFIFO_TFIFO);
+
+ 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_IDR, 0xFFFFFFFF);
+
+ /* Disable TX RX */
+ set_reg(UART_REG_CTRL, UART_CTRL_TXDIS | UART_CTRL_RXDIS);
+
+ /* Configure baudrate */
+ if (in_freq && baudrate) {
+ set_reg(UART_REG_BRGR, UART_BRGR_CD_CLKDIVISOR);
+ set_reg(UART_REG_BDIVR,
+ uart_min_clk_divisor(in_freq, baudrate));
+ }
+
+ /* Software reset TX RX data path and enable TX RX */
+ set_reg(UART_REG_CTRL, UART_CTRL_TXRES | UART_CTRL_RXRES
+ | UART_CTRL_TXEN | UART_CTRL_RXEN);
+
+ /*
+ * 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_MODE, UART_MODE_PAR_NONE);
+
+ sbi_console_set_device(&cadence_console);
+
+ return 0;
+}
diff --git a/lib/utils/serial/fdt_serial_cadence.c b/lib/utils/serial/fdt_serial_cadence.c
new file mode 100644
index 0000000..946e533
--- /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 = { 0 };
+
+ rc = fdt_parse_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/fdt_serial_uart8250.c b/lib/utils/serial/fdt_serial_uart8250.c
index 0b95f2d..7b5d6a4 100644
--- a/lib/utils/serial/fdt_serial_uart8250.c
+++ b/lib/utils/serial/fdt_serial_uart8250.c
@@ -17,7 +17,7 @@ static int serial_uart8250_init(void *fdt, int nodeoff,
int rc;
struct platform_uart_data uart = { 0 };
- rc = fdt_parse_uart8250_node(fdt, nodeoff, &uart);
+ rc = fdt_parse_uart_node(fdt, nodeoff, &uart);
if (rc)
return rc;
diff --git a/lib/utils/serial/objects.mk b/lib/utils/serial/objects.mk
index fa9f5a3..efb1d9e 100644
--- a/lib/utils/serial/objects.mk
+++ b/lib/utils/serial/objects.mk
@@ -10,6 +10,9 @@
libsbiutils-objs-$(CONFIG_FDT_SERIAL) += serial/fdt_serial.o
libsbiutils-objs-$(CONFIG_FDT_SERIAL) += serial/fdt_serial_drivers.o
+carray-fdt_serial_drivers-$(CONFIG_FDT_SERIAL_CADENCE) += fdt_serial_cadence
+libsbiutils-objs-$(CONFIG_FDT_SERIAL_CADENCE) += serial/fdt_serial_cadence.o
+
carray-fdt_serial_drivers-$(CONFIG_FDT_SERIAL_GAISLER) += fdt_serial_gaisler
libsbiutils-objs-$(CONFIG_FDT_SERIAL_GAISLER) += serial/fdt_serial_gaisler.o
@@ -31,6 +34,7 @@ libsbiutils-objs-$(CONFIG_FDT_SERIAL_UART8250) += serial/fdt_serial_uart8250.o
carray-fdt_serial_drivers-$(CONFIG_FDT_SERIAL_XILINX_UARTLITE) += fdt_serial_xlnx_uartlite
libsbiutils-objs-$(CONFIG_FDT_SERIAL_XILINX_UARTLITE) += serial/fdt_serial_xlnx_uartlite.o
+libsbiutils-objs-$(CONFIG_SERIAL_CADENCE) += serial/cadence-uart.o
libsbiutils-objs-$(CONFIG_SERIAL_GAISLER) += serial/gaisler-uart.o
libsbiutils-objs-$(CONFIG_SERIAL_SHAKTI) += serial/shakti-uart.o
libsbiutils-objs-$(CONFIG_SERIAL_SIFIVE) += serial/sifive-uart.o
diff --git a/platform/generic/configs/defconfig b/platform/generic/configs/defconfig
index 2a75394..e324173 100644
--- a/platform/generic/configs/defconfig
+++ b/platform/generic/configs/defconfig
@@ -18,6 +18,7 @@ CONFIG_FDT_RESET_SIFIVE_TEST=y
CONFIG_FDT_RESET_SUNXI_WDT=y
CONFIG_FDT_RESET_THEAD=y
CONFIG_FDT_SERIAL=y
+CONFIG_FDT_SERIAL_CADENCE=y
CONFIG_FDT_SERIAL_GAISLER=y
CONFIG_FDT_SERIAL_HTIF=y
CONFIG_FDT_SERIAL_SHAKTI=y
--
2.37.1
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