Changeset 8a9a41e in mainline for kernel/genarch/src/drivers/ns16550/ns16550.c

Timestamp:

2021-10-24T08:28:43Z (4 years ago)

Author:

GitHub <noreply@…>

Children:

9ea3a41

Parents:

2ce943a (diff), cd981f2a (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
Use the (diff) links above to see all the changes relative to each parent.

git-author:

Erik Kučák <35500848+Riko196@…> (2021-10-24 08:28:43)

git-committer:

GitHub <noreply@…> (2021-10-24 08:28:43)

Message:

Merge branch 'HelenOS:master' into master

File:

• kernel/genarch/src/drivers/ns16550/ns16550.c (modified) (1 diff)

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

@@ -132 +132 @@
 };
 
+/** Configure ns16550 transmission format.
+ *
+ * @param instance   NS 16550 driver instance.
+ * @param baud_rate  Transmission speed in bits per second, also known as baud,
+ *                   maximum value is 115200.
+ * @param lcr_format Line Control Register configuration bits, as defined by
+ *                   the @c LCR_ macros.  These configure the word width,
+ *                   parity type, and stop bit count.
+ */
+void ns16550_format_set(ns16550_instance_t *instance,
+    unsigned baud_rate, uint8_t lcr_format)
+{
+        uint16_t divisor;
+
+        divisor = (uint16_t)(NS156440_CLOCK / baud_rate);
+        if (divisor == 0)
+                divisor = 1;  /* Avoid division by zero. */
+
+        ns16550_reg_write(instance, NS16550_REG_LCR, LCR_DLAB);
+        ns16550_reg_write(instance, NS16550_REG_DLL, divisor & 0xFF);
+        ns16550_reg_write(instance, NS16550_REG_DLH, (divisor >> 8) & 0xFF);
+        ns16550_reg_write(instance, NS16550_REG_LCR, lcr_format & ~LCR_DLAB);
+}
+
 /** Initialize ns16550.
  *