[Xen-devel] [PATCH V4 5/5] xen/arm: Add early printk support for SCIFA compatible UARTs

[Oleksandr Tyshchenko <olekstysh@xxxxxxxxx>]

From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>

This patch makes possible to use existing early prink code
for Renesas "Stout" board based on R-Car H2 SoC (SCIFA).

The "EARLY_PRINTK_VERSION" for that board should be 'A':
CONFIG_EARLY_PRINTK=scif,0xe6c40000,A

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
CC: Julien Grall <julien.grall@xxxxxxx>

---
    Changes in v3:
        - It was decided not to introduce new debug-scifa.inc
          for handling SCIFA interface, but to extend existing
          debug-scif.inc for handling both interfaces.
          This patch is a result of splitting an initial patch
          "xen/arm: Add SCIFA UART support for early printk"
          and only adds a support.

    Changes in v4:
        - Drop SCIF(A) from comments
---
 xen/arch/arm/arm32/debug-scif.inc | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/xen/arch/arm/arm32/debug-scif.inc 
b/xen/arch/arm/arm32/debug-scif.inc
index a8d2eae..3f01c90 100644
--- a/xen/arch/arm/arm32/debug-scif.inc
+++ b/xen/arch/arm/arm32/debug-scif.inc
@@ -1,7 +1,7 @@
 /*
  * xen/arch/arm/arm32/debug-scif.inc
  *
- * SCIF specific debug code
+ * SCIF(A) specific debug code
  *
  * Oleksandr Tyshchenko <oleksandr.tyshchenko@xxxxxxxxxxxxxxx>
  * Copyright (C) 2014, Globallogic.
@@ -22,10 +22,13 @@
 #ifdef EARLY_PRINTK_VERSION_NONE
 #define STATUS_REG    SCIF_SCFSR
 #define TX_FIFO_REG   SCIF_SCFTDR
+#elif EARLY_PRINTK_VERSION_A
+#define STATUS_REG    SCIFA_SCASSR
+#define TX_FIFO_REG   SCIFA_SCAFTDR
 #endif
 
 /*
- * SCIF UART wait UART to be ready to transmit
+ * Wait UART to be ready to transmit
  * rb: register which contains the UART base address
  * rc: scratch register
  */
@@ -37,7 +40,7 @@
 .endm
 
 /*
- * SCIF UART transmit character
+ * UART transmit character
  * rb: register which contains the UART base address
  * rt: register which contains the character to transmit
  */
-- 
2.7.4


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