diff mbox series

[V4,2/5] xen/arm: drivers: scif: Extend driver to handle other interfaces

Message ID 1555513175-7596-3-git-send-email-olekstysh@gmail.com (mailing list archive)
State Superseded
Headers show
Series Renesas Stout board support (R-Car Gen2) | expand

Commit Message

Oleksandr Tyshchenko April 17, 2019, 2:59 p.m. UTC 
From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>

Extend driver to be able to handle other SCIF(X) compatible
interfaces as well. These interfaces have lot in common,
but mostly differ in offsets and bits for some registers.

For example, the main difference between SCIF and SCIFA interfaces
from "scif-uart" driver's point of view:
- Registers offset: serial status, receive/transmit FIFO data
  registers have different offset
- Internal FIFO size: 64 bytes for SCIFA and 16 bytes for SCIF
- Overrun bit location: serial status register for SCIFA and
  dedicated line status register for SCIF

Introduce "port_params" array to keep interface specific things.

The "data" field in struct dt_device_match is used for recognizing
what interface is present on a target board.

Please note, nothing has been technically changed for Renesas "Lager"
and other supported boards (SCIF).

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
CC: Julien Grall <julien.grall@arm.com>

---
    Changes in v2:
        - Name a enum for describing interfaces this driver supports
        - Use local variable for "params" where appropriate
        - Use "data" field in struct dt_device_match instead of calling
          dt_device_is_compatible()
        - Don't check for "overrun_reg != status_reg" condition during
          initialization

    Changes in v3:
        - This patch is a result of splitting an initial patch
          "xen/arm: drivers: scif: Add support for SCIFA compatible UARTs"
          and only reworks a driver
        - Drop "port_type" variable from scif_uart_init(), pass a pointer
          directly

    Changes in v4:
        - Add ASSERT(match) in scif_uart_init()
        - Drop "if ( params->overrun_reg != params->status_reg )" check
          in scif_uart_interrupt() and scif_uart_init_postirq()
        - Add an explanation to commit message
---
 xen/drivers/char/scif-uart.c    | 114 ++++++++++++++++++++++++++++------------
 xen/include/asm-arm/scif-uart.h |   4 --
 2 files changed, 80 insertions(+), 38 deletions(-)

Comments

Julien Grall April 29, 2019, 12:51 p.m. UTC | #1 
Hi Oleksandr,

On 17/04/2019 15:59, Oleksandr Tyshchenko wrote:
> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
> 
> Extend driver to be able to handle other SCIF(X) compatible
> interfaces as well. These interfaces have lot in common,
> but mostly differ in offsets and bits for some registers.
> 
> For example, the main difference between SCIF and SCIFA interfaces
> from "scif-uart" driver's point of view:
> - Registers offset: serial status, receive/transmit FIFO data
>    registers have different offset
> - Internal FIFO size: 64 bytes for SCIFA and 16 bytes for SCIF
> - Overrun bit location: serial status register for SCIFA and
>    dedicated line status register for SCIF
> 
> Introduce "port_params" array to keep interface specific things.
> 
> The "data" field in struct dt_device_match is used for recognizing
> what interface is present on a target board.
> 
> Please note, nothing has been technically changed for Renesas "Lager"
> and other supported boards (SCIF).
> 
> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
> CC: Julien Grall <julien.grall@arm.com>

Acked-by: Julien Grall <julien.grall@arm.com>

Cheers,
diff mbox series

Patch

diff --git a/xen/drivers/char/scif-uart.c b/xen/drivers/char/scif-uart.c
index 465fb34..85483ee 100644
--- a/xen/drivers/char/scif-uart.c
+++ b/xen/drivers/char/scif-uart.c
@@ -40,16 +40,51 @@  static struct scif_uart {
     char __iomem *regs;
     struct irqaction irqaction;
     struct vuart_info vuart;
+    const struct port_params *params;
 } scif_com = {0};
 
+enum port_types
+{
+    SCIF_PORT,
+    NR_PORTS,
+};
+
+struct port_params
+{
+    unsigned int status_reg;
+    unsigned int tx_fifo_reg;
+    unsigned int rx_fifo_reg;
+    unsigned int overrun_reg;
+    unsigned int overrun_mask;
+    unsigned int error_mask;
+    unsigned int irq_flags;
+    unsigned int fifo_size;
+};
+
+static const struct port_params port_params[NR_PORTS] =
+{
+    [SCIF_PORT] =
+    {
+        .status_reg   = SCIF_SCFSR,
+        .tx_fifo_reg  = SCIF_SCFTDR,
+        .rx_fifo_reg  = SCIF_SCFRDR,
+        .overrun_reg  = SCIF_SCLSR,
+        .overrun_mask = SCLSR_ORER,
+        .error_mask   = SCFSR_PER | SCFSR_FER | SCFSR_BRK | SCFSR_ER,
+        .irq_flags    = SCSCR_RIE | SCSCR_TIE | SCSCR_REIE,
+        .fifo_size    = 16,
+    },
+};
+
 static void scif_uart_interrupt(int irq, void *data, struct cpu_user_regs *regs)
 {
     struct serial_port *port = data;
     struct scif_uart *uart = port->uart;
+    const struct port_params *params = uart->params;
     uint16_t status, ctrl;
 
     ctrl = scif_readw(uart, SCIF_SCSCR);
-    status = scif_readw(uart, SCIF_SCFSR) & ~SCFSR_TEND;
+    status = scif_readw(uart, params->status_reg) & ~SCFSR_TEND;
     /* Ignore next flag if TX Interrupt is disabled */
     if ( !(ctrl & SCSCR_TIE) )
         status &= ~SCFSR_TDFE;
@@ -65,13 +100,13 @@  static void scif_uart_interrupt(int irq, void *data, struct cpu_user_regs *regs)
             serial_rx_interrupt(port, regs);
 
         /* Error Interrupt */
-        if ( status & SCIF_ERRORS )
-            scif_writew(uart, SCIF_SCFSR, ~SCIF_ERRORS);
-        if ( scif_readw(uart, SCIF_SCLSR) & SCLSR_ORER )
-            scif_writew(uart, SCIF_SCLSR, 0);
+        if ( status & params->error_mask )
+            scif_writew(uart, params->status_reg, ~params->error_mask);
+        if ( scif_readw(uart, params->overrun_reg) & params->overrun_mask )
+            scif_writew(uart, params->overrun_reg, ~params->overrun_mask);
 
         ctrl = scif_readw(uart, SCIF_SCSCR);
-        status = scif_readw(uart, SCIF_SCFSR) & ~SCFSR_TEND;
+        status = scif_readw(uart, params->status_reg) & ~SCFSR_TEND;
         /* Ignore next flag if TX Interrupt is disabled */
         if ( !(ctrl & SCSCR_TIE) )
             status &= ~SCFSR_TDFE;
@@ -81,12 +116,13 @@  static void scif_uart_interrupt(int irq, void *data, struct cpu_user_regs *regs)
 static void __init scif_uart_init_preirq(struct serial_port *port)
 {
     struct scif_uart *uart = port->uart;
+    const struct port_params *params = uart->params;
 
     /*
      * Wait until last bit has been transmitted. This is needed for a smooth
      * transition when we come from early printk
      */
-    while ( !(scif_readw(uart, SCIF_SCFSR) & SCFSR_TEND) );
+    while ( !(scif_readw(uart, params->status_reg) & SCFSR_TEND) );
 
     /* Disable TX/RX parts and all interrupts */
     scif_writew(uart, SCIF_SCSCR, 0);
@@ -95,10 +131,10 @@  static void __init scif_uart_init_preirq(struct serial_port *port)
     scif_writew(uart, SCIF_SCFCR, SCFCR_RFRST | SCFCR_TFRST);
 
     /* Clear all errors and flags */
-    scif_readw(uart, SCIF_SCFSR);
-    scif_writew(uart, SCIF_SCFSR, 0);
-    scif_readw(uart, SCIF_SCLSR);
-    scif_writew(uart, SCIF_SCLSR, 0);
+    scif_readw(uart, params->status_reg);
+    scif_writew(uart, params->status_reg, 0);
+    scif_readw(uart, params->overrun_reg);
+    scif_writew(uart, params->overrun_reg, 0);
 
     /* Setup trigger level for TX/RX FIFOs */
     scif_writew(uart, SCIF_SCFCR, SCFCR_RTRG11 | SCFCR_TTRG11);
@@ -111,6 +147,7 @@  static void __init scif_uart_init_preirq(struct serial_port *port)
 static void __init scif_uart_init_postirq(struct serial_port *port)
 {
     struct scif_uart *uart = port->uart;
+    const struct port_params *params = uart->params;
     int rc;
 
     uart->irqaction.handler = scif_uart_interrupt;
@@ -122,14 +159,14 @@  static void __init scif_uart_init_postirq(struct serial_port *port)
                 uart->irq);
 
     /* Clear all errors */
-    if ( scif_readw(uart, SCIF_SCFSR) & SCIF_ERRORS )
-        scif_writew(uart, SCIF_SCFSR, ~SCIF_ERRORS);
-    if ( scif_readw(uart, SCIF_SCLSR) & SCLSR_ORER )
-        scif_writew(uart, SCIF_SCLSR, 0);
+    if ( scif_readw(uart, params->status_reg) & params->error_mask )
+        scif_writew(uart, params->status_reg, ~params->error_mask);
+    if ( scif_readw(uart, params->overrun_reg) & params->overrun_mask )
+        scif_writew(uart, params->overrun_reg, ~params->overrun_mask);
 
     /* Enable TX/RX and Error Interrupts  */
     scif_writew(uart, SCIF_SCSCR, scif_readw(uart, SCIF_SCSCR) |
-                 SCSCR_TIE | SCSCR_RIE | SCSCR_REIE);
+                params->irq_flags);
 }
 
 static void scif_uart_suspend(struct serial_port *port)
@@ -145,43 +182,47 @@  static void scif_uart_resume(struct serial_port *port)
 static int scif_uart_tx_ready(struct serial_port *port)
 {
     struct scif_uart *uart = port->uart;
+    const struct port_params *params = uart->params;
     uint16_t cnt;
 
     /* Check for empty space in TX FIFO */
-    if ( !(scif_readw(uart, SCIF_SCFSR) & SCFSR_TDFE) )
+    if ( !(scif_readw(uart, params->status_reg) & SCFSR_TDFE) )
         return 0;
 
      /* Check number of data bytes stored in TX FIFO */
     cnt = scif_readw(uart, SCIF_SCFDR) >> 8;
-    ASSERT( cnt >= 0 && cnt <= SCIF_FIFO_MAX_SIZE );
+    ASSERT( cnt >= 0 && cnt <= params->fifo_size );
 
-    return (SCIF_FIFO_MAX_SIZE - cnt);
+    return (params->fifo_size - cnt);
 }
 
 static void scif_uart_putc(struct serial_port *port, char c)
 {
     struct scif_uart *uart = port->uart;
+    const struct port_params *params = uart->params;
 
-    scif_writeb(uart, SCIF_SCFTDR, c);
+    scif_writeb(uart, params->tx_fifo_reg, c);
     /* Clear required TX flags */
-    scif_writew(uart, SCIF_SCFSR, scif_readw(uart, SCIF_SCFSR) &
-                 ~(SCFSR_TEND | SCFSR_TDFE));
+    scif_writew(uart, params->status_reg,
+                scif_readw(uart, params->status_reg) &
+                ~(SCFSR_TEND | SCFSR_TDFE));
 }
 
 static int scif_uart_getc(struct serial_port *port, char *pc)
 {
     struct scif_uart *uart = port->uart;
+    const struct port_params *params = uart->params;
 
     /* Check for available data bytes in RX FIFO */
-    if ( !(scif_readw(uart, SCIF_SCFSR) & (SCFSR_RDF | SCFSR_DR)) )
+    if ( !(scif_readw(uart, params->status_reg) & (SCFSR_RDF | SCFSR_DR)) )
         return 0;
 
-    *pc = scif_readb(uart, SCIF_SCFRDR);
+    *pc = scif_readb(uart, params->rx_fifo_reg);
 
     /* dummy read */
-    scif_readw(uart, SCIF_SCFSR);
+    scif_readw(uart, params->status_reg);
     /* Clear required RX flags */
-    scif_writew(uart, SCIF_SCFSR, ~(SCFSR_RDF | SCFSR_DR));
+    scif_writew(uart, params->status_reg, ~(SCFSR_RDF | SCFSR_DR));
 
     return 1;
 }
@@ -229,9 +270,16 @@  static struct uart_driver __read_mostly scif_uart_driver = {
     .vuart_info   = scif_vuart_info,
 };
 
+static const struct dt_device_match scif_uart_dt_match[] __initconst =
+{
+    { .compatible = "renesas,scif",  .data = (void *)SCIF_PORT },
+    { /* sentinel */ },
+};
+
 static int __init scif_uart_init(struct dt_device_node *dev,
                                  const void *data)
 {
+    const struct dt_device_match *match;
     const char *config = data;
     struct scif_uart *uart;
     int res;
@@ -265,10 +313,14 @@  static int __init scif_uart_init(struct dt_device_node *dev,
         return -ENOMEM;
     }
 
+    match = dt_match_node(scif_uart_dt_match, dev);
+    ASSERT( match );
+    uart->params = &port_params[(enum port_types)match->data];
+
     uart->vuart.base_addr  = addr;
     uart->vuart.size       = size;
-    uart->vuart.data_off   = SCIF_SCFTDR;
-    uart->vuart.status_off = SCIF_SCFSR;
+    uart->vuart.data_off   = uart->params->tx_fifo_reg;
+    uart->vuart.status_off = uart->params->status_reg;
     uart->vuart.status     = SCFSR_TDFE;
 
     /* Register with generic serial driver */
@@ -279,12 +331,6 @@  static int __init scif_uart_init(struct dt_device_node *dev,
     return 0;
 }
 
-static const struct dt_device_match scif_uart_dt_match[] __initconst =
-{
-    DT_MATCH_COMPATIBLE("renesas,scif"),
-    { /* sentinel */ },
-};
-
 DT_DEVICE_START(scif_uart, "SCIF UART", DEVICE_SERIAL)
     .dt_match = scif_uart_dt_match,
     .init = scif_uart_init,
diff --git a/xen/include/asm-arm/scif-uart.h b/xen/include/asm-arm/scif-uart.h
index 8137850..c343f2f 100644
--- a/xen/include/asm-arm/scif-uart.h
+++ b/xen/include/asm-arm/scif-uart.h
@@ -21,8 +21,6 @@ 
 #ifndef __ASM_ARM_SCIF_UART_H
 #define __ASM_ARM_SCIF_UART_H
 
-#define SCIF_FIFO_MAX_SIZE    16
-
 /* Register offsets */
 #define SCIF_SCSMR     (0x00)    /* Serial mode register           */
 #define SCIF_SCBRR     (0x04)    /* Bit rate register              */
@@ -57,8 +55,6 @@ 
 #define SCFSR_RDF     (1 << 1)    /* Receive FIFO Data Full */
 #define SCFSR_DR      (1 << 0)    /* Receive Data Ready */
 
-#define SCIF_ERRORS    (SCFSR_PER | SCFSR_FER | SCFSR_ER | SCFSR_BRK)
-
 /* Line Status Register (SCLSR) */
 #define SCLSR_TO      (1 << 2)    /* Timeout */
 #define SCLSR_ORER    (1 << 0)    /* Overrun Error */