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authorinmarket <andrewh@inmarket.com.au>2014-07-15 12:41:40 +1000
committerinmarket <andrewh@inmarket.com.au>2014-07-15 12:41:40 +1000
commit0e74c164c3eac14f6e99d1a5cc4e0563faeff5d0 (patch)
treead1e2e9942db826dfaaf681c8a0cef48a87eabf2 /boards/base/RaspberryPi/rpi_mailbox.c
parent92d972cfd83b67961dc63d60c5317ec2651eb256 (diff)
parentdb4719bd1d3cef2597f1bf443f8d82a27f233eae (diff)
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Merge branch 'master' into newmouse
Diffstat (limited to 'boards/base/RaspberryPi/rpi_mailbox.c')
-rw-r--r--boards/base/RaspberryPi/rpi_mailbox.c47
1 files changed, 47 insertions, 0 deletions
diff --git a/boards/base/RaspberryPi/rpi_mailbox.c b/boards/base/RaspberryPi/rpi_mailbox.c
new file mode 100644
index 00000000..798cbb1f
--- /dev/null
+++ b/boards/base/RaspberryPi/rpi_mailbox.c
@@ -0,0 +1,47 @@
+/*
+ * Access system mailboxes
+ */
+#include "rpi_mailbox.h"
+
+/* Mailbox memory addresses */
+static volatile unsigned int *MAILBOX0READ = (unsigned int *) (0x2000b880);
+static volatile unsigned int *MAILBOX0STATUS = (unsigned int *) (0x2000b898);
+static volatile unsigned int *MAILBOX0WRITE = (unsigned int *) (0x2000b8a0);
+
+/* Bit 31 set in status register if the write mailbox is full */
+#define MAILBOX_FULL 0x80000000
+
+/* Bit 30 set in status register if the read mailbox is empty */
+#define MAILBOX_EMPTY 0x40000000
+
+unsigned int rpi_readmailbox(unsigned int channel)
+{
+ unsigned int val;
+
+ if (channel > 15)
+ return 0xFFFFFFFF;
+
+ /* Wait for mailbox to be full */
+ while (*MAILBOX0STATUS & MAILBOX_EMPTY);
+
+ val = *MAILBOX0READ;
+
+ if ((val & 15) == channel)
+ return (val & 0xFFFFFFF0);
+ else
+ return 0xFFFFFFFF;
+}
+
+void rpi_writemailbox(unsigned int channel, unsigned int data)
+{
+ if (channel > 15)
+ return;
+
+ if (data & 0x000F)
+ return;
+
+ /* Wait for mailbox to be not full */
+ while (*MAILBOX0STATUS & MAILBOX_FULL);
+
+ *MAILBOX0WRITE = (data | channel);
+}