Changeset 38b0ae2 in mainline for kernel/genarch/src/drivers/ns16550/ns16550.c

Timestamp:

2018-02-12T20:16:44Z (7 years ago)

Author:

GitHub <noreply@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

448e093

Parents:

8192d8a

git-author:

Jiří Zárevúcky <zarevucky.jiri@…> (2018-02-12 20:16:44)

git-committer:

GitHub <noreply@…> (2018-02-12 20:16:44)

Message:

Generalize ns16550 driver to work with more chips. (#20)

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);
 }