[PATCH 2/3 v3] xen: Add support for initializing 16550 UART using ACPI

[Bhupinder Thakur <bhupinder.thakur@linaro.org>]

Currently, Xen supports only DT based initialization of 16550 UART.
This patch adds support for initializing 16550 UART using ACPI SPCR table.

Signed-off-by: Bhupinder Thakur <bhupinder.thakur@linaro.org>
---
Changes since v2:
- renamed UART_MAX_REG to UART_NUM_REGS
- aligned some assignment statements
- some coding style changes

CC: Andrew Cooper <andrew.cooper3@citrix.com>
CC: George Dunlap <George.Dunlap@eu.citrix.com>
CC: Ian Jackson <ian.jackson@eu.citrix.com>
CC: Jan Beulich <jbeulich@suse.com>
CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Tim Deegan <tim@xen.org>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Julien Grall <julien.grall@arm.com>

 xen/drivers/char/ns16550.c  | 67 +++++++++++++++++++++++++++++++++++++++++++++
 xen/include/xen/8250-uart.h |  1 +
 2 files changed, 68 insertions(+)

diff --git a/xen/drivers/char/ns16550.c b/xen/drivers/char/ns16550.c
index c5dfc1e..af4712f 100644
--- a/xen/drivers/char/ns16550.c
+++ b/xen/drivers/char/ns16550.c
@@ -29,6 +29,10 @@
 #ifdef CONFIG_X86
 #include <asm/fixmap.h>
 #endif
+#ifdef CONFIG_ACPI
+#include <xen/acpi.h>
+#endif
+
 
 /*
  * Configure serial port with a string:
@@ -1565,6 +1569,69 @@ DT_DEVICE_START(ns16550, "NS16550 UART", DEVICE_SERIAL)
 DT_DEVICE_END
 
 #endif /* HAS_DEVICE_TREE */
+
+#if defined(CONFIG_ACPI) && defined(CONFIG_ARM)
+
+static int ns16550_init_acpi(struct ns16550 **puart)
+{
+    struct acpi_table_spcr *spcr;
+    int status;
+    struct ns16550 *uart = &ns16550_com[0];
+
+    ns16550_init_common(uart);
+
+    status = acpi_get_table(ACPI_SIG_SPCR, 0,
+                            (struct acpi_table_header **)&spcr);
+
+    if ( ACPI_FAILURE(status) )
+    {
+        printk("ns16550: Failed to get SPCR table\n");
+        return -EINVAL;
+    }
+
+    uart->baud      = BAUD_AUTO;
+    uart->data_bits = 8;
+    uart->parity    = spcr->parity;
+    uart->stop_bits = spcr->stop_bits;
+    uart->io_base   = spcr->serial_port.address;
+    uart->irq       = spcr->interrupt;
+    uart->reg_width = spcr->serial_port.bit_width / 8;
+    uart->reg_shift = 0;
+    uart->io_size   = UART_NUM_REGS << uart->reg_shift;
+
+    irq_set_type(spcr->interrupt, spcr->interrupt_type);
+
+    *puart = uart;
+
+    return 0;
+}
+
+static int __init ns16550_acpi_uart_init(const void *data)
+{
+    int ret;
+    struct ns16550 *uart;
+
+    ret = ns16550_init_acpi(&uart);
+    if ( ret )
+        return ret;
+
+    ns16550_vuart_init(uart);
+
+    ns16550_register_uart(uart);
+
+    return 0;
+}
+
+ACPI_DEVICE_START(ns16550c, "16550 COMPAT UART", DEVICE_SERIAL)
+        .class_type = ACPI_DBG2_16550_COMPATIBLE,
+        .init = ns16550_acpi_uart_init,
+ACPI_DEVICE_END
+ACPI_DEVICE_START(ns16550s, "16550 SUBSET UART", DEVICE_SERIAL)
+        .class_type = ACPI_DBG2_16550_SUBSET,
+        .init = ns16550_acpi_uart_init,
+ACPI_DEVICE_END
+
+#endif
 /*
  * Local variables:
  * mode: C
diff --git a/xen/include/xen/8250-uart.h b/xen/include/xen/8250-uart.h
index 5c3bac3..849a5c0 100644
--- a/xen/include/xen/8250-uart.h
+++ b/xen/include/xen/8250-uart.h
@@ -35,6 +35,7 @@
 #define UART_USR          0x1f    /* Status register (DW) */
 #define UART_DLL          0x00    /* divisor latch (ls) (DLAB=1) */
 #define UART_DLM          0x01    /* divisor latch (ms) (DLAB=1) */
+#define UART_NUM_REGS     (UART_USR + 1)
 
 /* Interrupt Enable Register */
 #define UART_IER_ERDAI    0x01    /* rx data recv'd       */
-- 
2.7.4


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel