From 136e0ab99b22378e3ff7d54f799a3a329316e869 Mon Sep 17 00:00:00 2001
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Date: Tue, 6 Aug 2019 12:43:16 +0300
Subject: [PATCH] serial: 8250_dw: split Synopsys DesignWare 8250 common functions
Git-commit: 136e0ab99b22378e3ff7d54f799a3a329316e869
Patch-mainline: v5.4-rc1
References: jsc#SLE-13436
We would like to use same functions in the couple of drivers for
Synopsys DesignWare 8250 UART. Split them from 8250_dw into new brand
library module which users will select explicitly.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20190806094322.64987-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/tty/serial/8250/8250_dwlib.c | 126 +++++++++++++++++++++++++++++++++++
drivers/tty/serial/8250/8250_dwlib.h | 19 ++++++
drivers/tty/serial/8250/Kconfig | 3 +
drivers/tty/serial/8250/Makefile | 1 +
4 files changed, 149 insertions(+)
create mode 100644 drivers/tty/serial/8250/8250_dwlib.c
create mode 100644 drivers/tty/serial/8250/8250_dwlib.h
diff --git a/drivers/tty/serial/8250/8250_dwlib.c b/drivers/tty/serial/8250/8250_dwlib.c
new file mode 100644
index 000000000000..6d6a78eead3e
--- /dev/null
+++ b/drivers/tty/serial/8250/8250_dwlib.c
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* Synopsys DesignWare 8250 library. */
+
+#include <linux/bitops.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/serial_8250.h>
+#include <linux/serial_core.h>
+
+#include "8250_dwlib.h"
+
+/* Offsets for the DesignWare specific registers */
+#define DW_UART_DLF 0xc0 /* Divisor Latch Fraction Register */
+#define DW_UART_CPR 0xf4 /* Component Parameter Register */
+#define DW_UART_UCV 0xf8 /* UART Component Version */
+
+/* Component Parameter Register bits */
+#define DW_UART_CPR_ABP_DATA_WIDTH (3 << 0)
+#define DW_UART_CPR_AFCE_MODE (1 << 4)
+#define DW_UART_CPR_THRE_MODE (1 << 5)
+#define DW_UART_CPR_SIR_MODE (1 << 6)
+#define DW_UART_CPR_SIR_LP_MODE (1 << 7)
+#define DW_UART_CPR_ADDITIONAL_FEATURES (1 << 8)
+#define DW_UART_CPR_FIFO_ACCESS (1 << 9)
+#define DW_UART_CPR_FIFO_STAT (1 << 10)
+#define DW_UART_CPR_SHADOW (1 << 11)
+#define DW_UART_CPR_ENCODED_PARMS (1 << 12)
+#define DW_UART_CPR_DMA_EXTRA (1 << 13)
+#define DW_UART_CPR_FIFO_MODE (0xff << 16)
+
+/* Helper for FIFO size calculation */
+#define DW_UART_CPR_FIFO_SIZE(a) (((a >> 16) & 0xff) * 16)
+
+static inline u32 dw8250_readl_ext(struct uart_port *p, int offset)
+{
+ if (p->iotype == UPIO_MEM32BE)
+ return ioread32be(p->membase + offset);
+ return readl(p->membase + offset);
+}
+
+static inline void dw8250_writel_ext(struct uart_port *p, int offset, u32 reg)
+{
+ if (p->iotype == UPIO_MEM32BE)
+ iowrite32be(reg, p->membase + offset);
+ else
+ writel(reg, p->membase + offset);
+}
+
+/*
+ * divisor = div(I) + div(F)
+ * "I" means integer, "F" means fractional
+ * quot = div(I) = clk / (16 * baud)
+ * frac = div(F) * 2^dlf_size
+ *
+ * let rem = clk % (16 * baud)
+ * we have: div(F) * (16 * baud) = rem
+ * so frac = 2^dlf_size * rem / (16 * baud) = (rem << dlf_size) / (16 * baud)
+ */
+static unsigned int dw8250_get_divisor(struct uart_port *p, unsigned int baud,
+ unsigned int *frac)
+{
+ unsigned int quot, rem, base_baud = baud * 16;
+ struct dw8250_port_data *d = p->private_data;
+
+ quot = p->uartclk / base_baud;
+ rem = p->uartclk % base_baud;
+ *frac = DIV_ROUND_CLOSEST(rem << d->dlf_size, base_baud);
+
+ return quot;
+}
+
+static void dw8250_set_divisor(struct uart_port *p, unsigned int baud,
+ unsigned int quot, unsigned int quot_frac)
+{
+ dw8250_writel_ext(p, DW_UART_DLF, quot_frac);
+ serial8250_do_set_divisor(p, baud, quot, quot_frac);
+}
+
+void dw8250_setup_port(struct uart_port *p)
+{
+ struct uart_8250_port *up = up_to_u8250p(p);
+ u32 reg;
+
+ /*
+ * If the Component Version Register returns zero, we know that
+ * ADDITIONAL_FEATURES are not enabled. No need to go any further.
+ */
+ reg = dw8250_readl_ext(p, DW_UART_UCV);
+ if (!reg)
+ return;
+
+ dev_dbg(p->dev, "Designware UART version %c.%c%c\n",
+ (reg >> 24) & 0xff, (reg >> 16) & 0xff, (reg >> 8) & 0xff);
+
+ dw8250_writel_ext(p, DW_UART_DLF, ~0U);
+ reg = dw8250_readl_ext(p, DW_UART_DLF);
+ dw8250_writel_ext(p, DW_UART_DLF, 0);
+
+ if (reg) {
+ struct dw8250_port_data *d = p->private_data;
+
+ d->dlf_size = fls(reg);
+ p->get_divisor = dw8250_get_divisor;
+ p->set_divisor = dw8250_set_divisor;
+ }
+
+ reg = dw8250_readl_ext(p, DW_UART_CPR);
+ if (!reg)
+ return;
+
+ /* Select the type based on FIFO */
+ if (reg & DW_UART_CPR_FIFO_MODE) {
+ p->type = PORT_16550A;
+ p->flags |= UPF_FIXED_TYPE;
+ p->fifosize = DW_UART_CPR_FIFO_SIZE(reg);
+ up->capabilities = UART_CAP_FIFO;
+ }
+
+ if (reg & DW_UART_CPR_AFCE_MODE)
+ up->capabilities |= UART_CAP_AFE;
+
+ if (reg & DW_UART_CPR_SIR_MODE)
+ up->capabilities |= UART_CAP_IRDA;
+}
+EXPORT_SYMBOL_GPL(dw8250_setup_port);
diff --git a/drivers/tty/serial/8250/8250_dwlib.h b/drivers/tty/serial/8250/8250_dwlib.h
new file mode 100644
index 000000000000..87a4db2a8aba
--- /dev/null
+++ b/drivers/tty/serial/8250/8250_dwlib.h
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* Synopsys DesignWare 8250 library header file. */
+
+#include <linux/types.h>
+
+#include "8250.h"
+
+struct dw8250_port_data {
+ /* Port properties */
+ int line;
+
+ /* DMA operations */
+ struct uart_8250_dma dma;
+
+ /* Hardware configuration */
+ u8 dlf_size;
+};
+
+void dw8250_setup_port(struct uart_port *p);
diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index 509f6a3bb9ff..d628258fb4cf 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -314,6 +314,9 @@ config SERIAL_8250_RSA
If you don't have such card, or if unsure, say N.
+config SERIAL_8250_DWLIB
+ bool
+
config SERIAL_8250_ACORN
tristate "Acorn expansion card serial port support"
depends on ARCH_ACORN && SERIAL_8250
diff --git a/drivers/tty/serial/8250/Makefile b/drivers/tty/serial/8250/Makefile
index 18751bc63a84..9b451d81588b 100644
--- a/drivers/tty/serial/8250/Makefile
+++ b/drivers/tty/serial/8250/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_SERIAL_8250) += 8250.o 8250_base.o
8250-$(CONFIG_SERIAL_8250_PNP) += 8250_pnp.o
8250_base-y := 8250_port.o
8250_base-$(CONFIG_SERIAL_8250_DMA) += 8250_dma.o
+8250_base-$(CONFIG_SERIAL_8250_DWLIB) += 8250_dwlib.o
8250_base-$(CONFIG_SERIAL_8250_FINTEK) += 8250_fintek.o
obj-$(CONFIG_SERIAL_8250_GSC) += 8250_gsc.o
obj-$(CONFIG_SERIAL_8250_PCI) += 8250_pci.o
--
2.16.4