Changeset 466e75ad in mainline for kernel/genarch/src/drivers/ns16550/ns16550.c

Timestamp:

2018-02-12T18:58:50Z (8 years ago)

Author:

Jiří Zárevúcky <zarevucky.jiri@…>

Parents:

8192d8a

git-author:

Jiří Zárevúcky <zarevucky.jiri@…> (2018-02-12 17:25:25)

git-committer:

Jiří Zárevúcky <zarevucky.jiri@…> (2018-02-12 18:58:50)

Message:

Generalize ns16550 driver to work with more chips.

Some UART controllers are compatible with 16550A, but have more spacing
between registers. In particular, ARMADA 385, which is the basis of
Turris Omnia router, has a compatible UART with 32b registers instead of 8b
(with the top three bytes unused).

Note: The device tree file hints that some UARTs may need register reads/writes
that are wider than 8 bits, and this commit does not address that possibility.

File:

• kernel/genarch/src/drivers/ns16550/ns16550.c (modified) (8 diffs)

kernel/genarch/src/drivers/ns16550/ns16550.c

@@ -1 +1 @@
 /*
  * Copyright (c) 2009 Jakub Jermar
+ * Copyright (c) 2018 CZ.NIC, z.s.p.o.
  * All rights reserved.
  *
@@ -46 +47 @@
 #define LSR_TH_READY    0x20
 
+static inline uint8_t _read(ns16550_instance_t *inst, int reg) {
+        return pio_read_8(&inst->ns16550[reg << inst->reg_shift]);
+}
+
+static inline void _write(ns16550_instance_t *inst, int reg, uint8_t val) {
+        pio_write_8(&inst->ns16550[reg << inst->reg_shift], val);
+}
+
 static irq_ownership_t ns16550_claim(irq_t *irq)
 {
         ns16550_instance_t *instance = irq->instance;
-        ns16550_t *dev = instance->ns16550;
-        
-        if (pio_read_8(&dev->lsr) & LSR_DATA_READY)
+
+        if (_read(instance, NS16550_REG_LSR) & LSR_DATA_READY)
                 return IRQ_ACCEPT;
         else
@@ -60 +68 @@
 {
         ns16550_instance_t *instance = irq->instance;
-        ns16550_t *dev = instance->ns16550;
         
-        if (pio_read_8(&dev->lsr) & LSR_DATA_READY) {
-                uint8_t data = pio_read_8(&dev->rbr);
+        while (_read(instance, NS16550_REG_LSR) & LSR_DATA_READY) {
+                uint8_t data = _read(instance, NS16550_REG_RBR);
                 indev_push_character(instance->input, data);
         }
@@ -69 +76 @@
 
 /**< Clear input buffer. */
-static void ns16550_clear_buffer(ns16550_t *dev)
+static void ns16550_clear_buffer(ns16550_instance_t *instance)
 {
-        while ((pio_read_8(&dev->lsr) & LSR_DATA_READY))
-                (void) pio_read_8(&dev->rbr);
+        while (_read(instance, NS16550_REG_LSR) & LSR_DATA_READY)
+                (void) _read(instance, NS16550_REG_RBR);
 }
 
-static void ns16550_sendb(ns16550_t *dev, uint8_t byte)
+static void ns16550_sendb(ns16550_instance_t *instance, uint8_t byte)
 {
-        while (!(pio_read_8(&dev->lsr) & LSR_TH_READY))
+        while (!(_read(instance, NS16550_REG_LSR) & LSR_TH_READY))
                 ;
-        pio_write_8(&dev->thr, byte);
+        _write(instance, NS16550_REG_THR, byte);
 }
 
@@ -88 +95 @@
         if ((!instance->parea.mapped) || (console_override)) {
                 if (ascii_check(ch))
-                        ns16550_sendb(instance->ns16550, (uint8_t) ch);
+                        ns16550_sendb(instance, (uint8_t) ch);
                 else
-                        ns16550_sendb(instance->ns16550, U_SPECIAL);
+                        ns16550_sendb(instance, U_SPECIAL);
         }
 }
@@ -101 +108 @@
 /** Initialize ns16550.
  *
- * @param dev      Addrress of the beginning of the device in I/O space.
- * @param inr      Interrupt number.
- * @param cir      Clear interrupt function.
- * @param cir_arg  First argument to cir.
- * @param output   Where to store pointer to the output device
- *                 or NULL if the caller is not interested in
- *                 writing to the serial port.
+ * @param dev        Address of the beginning of the device in I/O space.
+ * @param reg_shift  Spacing between individual register addresses, in log2.
+ *                   The individual register location is calculated as
+ *                   `base + (register offset << reg_shift)`.
+ * @param inr        Interrupt number.
+ * @param cir        Clear interrupt function.
+ * @param cir_arg    First argument to cir.
+ * @param output     Where to store pointer to the output device
+ *                   or NULL if the caller is not interested in
+ *                   writing to the serial port.
  *
  * @return Keyboard instance or NULL on failure.
  *
  */
-ns16550_instance_t *ns16550_init(ns16550_t *dev, inr_t inr, cir_t cir,
-    void *cir_arg, outdev_t **output)
+ns16550_instance_t *ns16550_init(ioport8_t *dev, int reg_shift, inr_t inr,
+    cir_t cir, void *cir_arg, outdev_t **output)
 {
         ns16550_instance_t *instance
@@ -119 +129 @@
         if (instance) {
                 instance->ns16550 = dev;
+                instance->reg_shift = reg_shift;
                 instance->input = NULL;
                 instance->output = NULL;
@@ -162 +173 @@
         irq_register(&instance->irq);
         
-        ns16550_clear_buffer(instance->ns16550);
+        ns16550_clear_buffer(instance);
         
         /* Enable interrupts */
-        pio_write_8(&instance->ns16550->ier, IER_ERBFI);
-        pio_write_8(&instance->ns16550->mcr, MCR_OUT2);
+        _write(instance, NS16550_REG_IER, IER_ERBFI);
+        _write(instance, NS16550_REG_MCR, MCR_OUT2);
 }