MIPS: Alchemy: devboard register abstraction

All Alchemy development boards have external CPLDs with a few registers
in them.  They all share an identical register layout with only a few
minor differences (except the PB1000) in bit functions and base
addresses.

This patch
- adds a primitive facility to initialize and use these external
  registers,
- replaces all occurrences of bcsr->xxx accesses with calls to the new
  functions (the pb1200 cascade irq handling code is special).
- collects BCSR register information scattered throughout the board
  headers in a central place.

Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 76 insertions, 0 deletions

diff --git a/arch/mips/alchemy/devboards/bcsr.c b/arch/mips/alchemy/devboards/bcsr.c
new file mode 100644
index 0000000..85b7715
--- /dev/null
+++ b/arch/mips/alchemy/devboards/bcsr.c
@@ -0,0 +1,76 @@
+/*
+ * bcsr.h -- Db1xxx/Pb1xxx Devboard CPLD registers ("BCSR") abstraction.
+ *
+ * All Alchemy development boards (except, of course, the weird PB1000)
+ * have a few registers in a CPLD with standardised layout; they mostly
+ * only differ in base address.
+ * All registers are 16bits wide with 32bit spacing.
+ */
+
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <asm/addrspace.h>
+#include <asm/io.h>
+#include <asm/mach-db1x00/bcsr.h>
+
+static struct bcsr_reg {
+	void __iomem *raddr;
+	spinlock_t lock;
+} bcsr_regs[BCSR_CNT];
+
+void __init bcsr_init(unsigned long bcsr1_phys, unsigned long bcsr2_phys)
+{
+	int i;
+
+	bcsr1_phys = KSEG1ADDR(CPHYSADDR(bcsr1_phys));
+	bcsr2_phys = KSEG1ADDR(CPHYSADDR(bcsr2_phys));
+
+	for (i = 0; i < BCSR_CNT; i++) {
+		if (i >= BCSR_HEXLEDS)
+			bcsr_regs[i].raddr = (void __iomem *)bcsr2_phys +
+					(0x04 * (i - BCSR_HEXLEDS));
+		else
+			bcsr_regs[i].raddr = (void __iomem *)bcsr1_phys +
+					(0x04 * i);
+
+		spin_lock_init(&bcsr_regs[i].lock);
+	}
+}
+
+unsigned short bcsr_read(enum bcsr_id reg)
+{
+	unsigned short r;
+	unsigned long flags;
+
+	spin_lock_irqsave(&bcsr_regs[reg].lock, flags);
+	r = __raw_readw(bcsr_regs[reg].raddr);
+	spin_unlock_irqrestore(&bcsr_regs[reg].lock, flags);
+	return r;
+}
+EXPORT_SYMBOL_GPL(bcsr_read);
+
+void bcsr_write(enum bcsr_id reg, unsigned short val)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&bcsr_regs[reg].lock, flags);
+	__raw_writew(val, bcsr_regs[reg].raddr);
+	wmb();
+	spin_unlock_irqrestore(&bcsr_regs[reg].lock, flags);
+}
+EXPORT_SYMBOL_GPL(bcsr_write);
+
+void bcsr_mod(enum bcsr_id reg, unsigned short clr, unsigned short set)
+{
+	unsigned short r;
+	unsigned long flags;
+
+	spin_lock_irqsave(&bcsr_regs[reg].lock, flags);
+	r = __raw_readw(bcsr_regs[reg].raddr);
+	r &= ~clr;
+	r |= set;
+	__raw_writew(r, bcsr_regs[reg].raddr);
+	wmb();
+	spin_unlock_irqrestore(&bcsr_regs[reg].lock, flags);
+}
+EXPORT_SYMBOL_GPL(bcsr_mod);