tty: amba-pl011: add support for ZTE UART (EXPERIMENTAL)

Add (incomplete) support for the ZTE UART to the AMBA PL011 driver.
This is similar to the ARM and ST variants, except it has a different
register address layout, and requires 32-bit accesses to the registers.
Use the newly introduced register tables and access size support to
cope with these differences.

Signed-off-by: Russell King <[e-mail]>
Reviewed-by: Peter Hurley <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/tty/serial/amba-pl011.c

···
 	.get_fifosize		= get_fifosize_st,
 };
 
+static const u16 pl011_zte_offsets[REG_ARRAY_SIZE] = {
+	[REG_DR] = ZX_UART011_DR,
+	[REG_FR] = ZX_UART011_FR,
+	[REG_LCRH_RX] = ZX_UART011_LCRH,
+	[REG_LCRH_TX] = ZX_UART011_LCRH,
+	[REG_IBRD] = ZX_UART011_IBRD,
+	[REG_FBRD] = ZX_UART011_FBRD,
+	[REG_CR] = ZX_UART011_CR,
+	[REG_IFLS] = ZX_UART011_IFLS,
+	[REG_IMSC] = ZX_UART011_IMSC,
+	[REG_RIS] = ZX_UART011_RIS,
+	[REG_MIS] = ZX_UART011_MIS,
+	[REG_ICR] = ZX_UART011_ICR,
+	[REG_DMACR] = ZX_UART011_DMACR,
+};
+
+static struct vendor_data vendor_zte = {
+	.reg_offset		= pl011_zte_offsets,
+	.access_32b		= true,
+	.ifls			= UART011_IFLS_RX4_8|UART011_IFLS_TX4_8,
+	.get_fifosize		= get_fifosize_arm,
+};
+
 /* Deals with DMA transactions */
 
 struct pl011_sgbuf {

include/linux/amba/serial.h

···
 #define ST_UART011_ABCR		0x100	/* Autobaud control register. */
 #define ST_UART011_ABIMSC	0x15C	/* Autobaud interrupt mask/clear register. */
 
+/*
+ * ZTE UART register offsets.  This UART has a radically different address
+ * allocation from the ARM and ST variants, so we list all registers here.
+ * We assume unlisted registers do not exist.
+ */
+#define ZX_UART011_DR		0x04
+#define ZX_UART011_FR		0x14
+#define ZX_UART011_IBRD		0x24
+#define ZX_UART011_FBRD		0x28
+#define ZX_UART011_LCRH		0x30
+#define ZX_UART011_CR		0x34
+#define ZX_UART011_IFLS		0x38
+#define ZX_UART011_IMSC		0x40
+#define ZX_UART011_RIS		0x44
+#define ZX_UART011_MIS		0x48
+#define ZX_UART011_ICR		0x4c
+#define ZX_UART011_DMACR	0x50
+
 #define UART011_DR_OE		(1 << 11)
 #define UART011_DR_BE		(1 << 10)
 #define UART011_DR_PE		(1 << 9)