Add Spreadtrum SoC bindings and serial driver support

Add a full sc9836-uart driver for SC9836 SoC which is based on the spreadtrum sharkl64 platform.
This driver also support earlycon.

drivers/tty/serial/sprd_serial.c new file +7 -0

+static inline void sprd_rx(struct uart_port *port)
+{
+	struct tty_port *tty = &port->state->port;
+	unsigned int ch, flag, lsr, max_count = SPRD_TIMEOUT;
+
+	while ((serial_in(port, SPRD_STS1) & 0x00ff) && max_count--) {
+		lsr = serial_in(port, SPRD_LSR);

drivers/tty/serial/sprd_serial.c new file +6 -0

+
+		uart_insert_char(port, lsr, SPRD_LSR_OE, ch, flag);
+	}
+
+	tty_flip_buffer_push(tty);
+}

Hi Chunyan Zhang,

On Wed, Jan 28, 2015 at 10:47:41AM +0800, Chunyan Zhang wrote:
[...]

Quoted 12 lines

drivers/tty/serial/sprd_serial.c new file +12 -0

+static inline void sprd_rx(struct uart_port *port)
+{
+     struct tty_port *tty = &port->state->port;
+     unsigned int ch, flag, lsr, max_count = SPRD_TIMEOUT;
+
+     while ((serial_in(port, SPRD_STS1) & 0x00ff) && max_count--) {
+             lsr = serial_in(port, SPRD_LSR);
+             ch = serial_in(port, SPRD_RXD);
+             flag = TTY_NORMAL;
+             port->icount.rx++;
+
+             if (lsr & (SPRD_LSR_BI | SPRD_LSR_PE |

drivers/tty/serial/sprd_serial.c line 241

Quoted 5 lines

drivers/tty/serial/sprd_serial.c new file +5 -0

+                     SPRD_LSR_FE | SPRD_LSR_OE))
+                     if (handle_lsr_errors(port, &lsr, &flag))
+                             continue;
+             if (uart_handle_sysrq_char(port, ch))
+                     continue;

My comment[1] on a previous version of this patch still stands. uart_handle_sysrq_char is a NOP when SUPPORT_SYSRQ is not defined.

Quoted 6 lines

drivers/tty/serial/sprd_serial.c new file +6 -0

+
+             uart_insert_char(port, lsr, SPRD_LSR_OE, ch, flag);
+     }
+
+     tty_flip_buffer_push(tty);
+}

[...]

drivers/tty/serial/sprd_serial.c line 539

Quoted 9 lines

drivers/tty/serial/sprd_serial.c new file +9 -0

+static void sprd_console_write(struct console *co, const char *s,
+                                   unsigned int count)
+{
+     struct uart_port *port = &sprd_port[co->index]->port;
+     int locked = 1;
+     unsigned long flags;
+
+     if (port->sysrq)
+             locked = 0;

The sysrq field of struct uart_port is only defined when CONFIG_SERIAL_CORE_CONSOLE or SUPPORT_SYSRQ are defined. You should #ifdef this part accordingly to avoid build breakage.

drivers/tty/serial/sprd_serial.c line 552

Quoted 13 lines

drivers/tty/serial/sprd_serial.c new file +13 -0

+     else if (oops_in_progress)
+             locked = spin_trylock_irqsave(&port->lock, flags);
+     else
+             spin_lock_irqsave(&port->lock, flags);
+
+     uart_console_write(port, s, count, sprd_console_putchar);
+
+     /* wait for transmitter to become empty */
+     wait_for_xmitr(port);
+
+     if (locked)
+             spin_unlock_irqrestore(&port->lock, flags);
+}

[1]

        http://article.gmane.org/gmane.linux.drivers.devicetree/106483

baruch

--
http://baruch.siach.name/blog/ ~. .~ Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
- [email protected] - tel: +972.2.679.5364, http://www.tkos.co.il -

Quoted 6 lines · Baruch Siach

drivers/tty/serial/sprd_serial.c line 241

Quoted 2 lines · Chunyan Zhang

drivers/tty/serial/sprd_serial.c new file +2 -0

+             if (uart_handle_sysrq_char(port, ch))
+                     continue;

My comment[1] on a previous version of this patch still stands. uart_handle_sysrq_char is a NOP when SUPPORT_SYSRQ is not defined.

yes, there are two definitions in serial_core.h, and it returns 0 when SUPPORT_SYSRQ is not defined.
so, I think my code behavior does not hurt, right?

Hi Lyra Zhang,

Quoted 8 lines · Lyra Zhang

Quoted 6 lines · Baruch Siach

drivers/tty/serial/sprd_serial.c line 241

Quoted 2 lines · Chunyan Zhang

drivers/tty/serial/sprd_serial.c new file +2 -0

+             if (uart_handle_sysrq_char(port, ch))
+                     continue;

My comment[1] on a previous version of this patch still stands. uart_handle_sysrq_char is a NOP when SUPPORT_SYSRQ is not defined.

Quoted 3 lines

yes, there are two definitions in serial_core.h, and it returns 0 when SUPPORT_SYSRQ is not defined.
so, I think my code behavior does not hurt, right?

Right. I just wanted to point out that you can easily define SUPPORT_SYSRQ as appropriate like many other serial drivers do to get sysrq support.

baruch

--
http://baruch.siach.name/blog/ ~. .~ Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
- [email protected] - tel: +972.2.679.5364, http://www.tkos.co.il -