[Xen-changelog] [xen staging] xen/arm: Extend SCIF early prink code to handle other interfaces

[patchbot@xxxxxxx]

commit 89a97016305b617b77cea9c4518f76f2e7e84e19
Author:     Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
AuthorDate: Thu May 2 20:00:21 2019 +0300
Commit:     Julien Grall <julien.grall@xxxxxxx>
CommitDate: Thu May 16 16:43:49 2019 +0100

    xen/arm: Extend SCIF early prink code to handle other interfaces
    
    Extend early prink code to be able to handle other SCIF(X)
    compatible interfaces as well. These interfaces have lot in common,
    but mostly differ in offsets and bits for some registers.
    
    Introduce "EARLY_PRINTK_VERSION" config option to choose which
    interface version should be used (to properly apply register offsets).
    
    Please note, nothing has been technically changed for Renesas "Lager"
    and other supported boards (SCIF).
    
    The "EARLY_PRINTK_VERSION" option for that board should be empty:
    CONFIG_EARLY_PRINTK=scif,0xe6e60000
    
    Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
    Acked-by: Julien Grall <julien.grall@xxxxxxx>
---
 docs/misc/arm/early-printk.txt    |  5 +++++
 xen/arch/arm/Rules.mk             |  7 +++++++
 xen/arch/arm/arm32/debug-scif.inc | 17 +++++++++++------
 3 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/docs/misc/arm/early-printk.txt b/docs/misc/arm/early-printk.txt
index b23c54f287..89e081e51e 100644
--- a/docs/misc/arm/early-printk.txt
+++ b/docs/misc/arm/early-printk.txt
@@ -27,6 +27,11 @@ CONFIG_EARLY_PRINTK=<INC>,<BASE_ADDRESS>,<OTHER_OPTIONS>
       If <BAUD_RATE> is not given then the code will not try to
       initialize the UART, so that bootloader or firmware settings can
      be used for maximum compatibility.
+  - scif,<BASE_ADDRESS>,<VERSION>
+    - SCIF<VERSION> is, optionally, the interface version of the UART.
+
+      If <VERSION> is not given then the default interface version (SCIF)
+      will be used.
   - For all other uarts there are no additional options.
 
 As a convenience it is also possible to select from a list of
diff --git a/xen/arch/arm/Rules.mk b/xen/arch/arm/Rules.mk
index f264592aef..3d9a0ed357 100644
--- a/xen/arch/arm/Rules.mk
+++ b/xen/arch/arm/Rules.mk
@@ -68,6 +68,13 @@ EARLY_PRINTK_INIT_UART := y
 EARLY_PRINTK_BAUD := $(word 3,$(EARLY_PRINTK_CFG))
 endif
 endif
+ifeq ($(EARLY_PRINTK_INC),scif)
+ifneq ($(word 3,$(EARLY_PRINTK_CFG)),)
+CFLAGS-y += -DEARLY_PRINTK_VERSION_$(word 3,$(EARLY_PRINTK_CFG))
+else
+CFLAGS-y += -DEARLY_PRINTK_VERSION_NONE
+endif
+endif
 
 ifneq ($(EARLY_PRINTK_INC),)
 EARLY_PRINTK := y
diff --git a/xen/arch/arm/arm32/debug-scif.inc 
b/xen/arch/arm/arm32/debug-scif.inc
index 143f05d4f7..6f60e015c0 100644
--- a/xen/arch/arm/arm32/debug-scif.inc
+++ b/xen/arch/arm/arm32/debug-scif.inc
@@ -19,28 +19,33 @@
 
 #include <asm/scif-uart.h>
 
+#ifdef EARLY_PRINTK_VERSION_NONE
+#define STATUS_REG    SCIF_SCFSR
+#define TX_FIFO_REG   SCIF_SCFTDR
+#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
  */
 .macro early_uart_ready rb rc
 1:
-        ldrh   \rc, [\rb, #SCIF_SCFSR]   /* <- SCFSR (status register) */
+        ldrh   \rc, [\rb, #STATUS_REG]   /* Read status register */
         tst    \rc, #SCFSR_TDFE          /* Check TDFE bit */
         beq    1b                        /* Wait for the UART to be ready */
 .endm
 
 /*
- * SCIF UART transmit character
+ * UART transmit character
  * rb: register which contains the UART base address
  * rt: register which contains the character to transmit
  */
 .macro early_uart_transmit rb rt
-        strb   \rt, [\rb, #SCIF_SCFTDR]                  /* -> SCFTDR (data 
register) */
-        ldrh   \rt, [\rb, #SCIF_SCFSR]                   /* <- SCFSR (status 
register) */
+        strb   \rt, [\rb, #TX_FIFO_REG]                  /* Write data 
register */
+        ldrh   \rt, [\rb, #STATUS_REG]                   /* Read status 
register */
         and    \rt, \rt, #(~(SCFSR_TEND | SCFSR_TDFE))   /* Clear TEND and 
TDFE bits */
-        strh   \rt, [\rb, #SCIF_SCFSR]                   /* -> SCFSR (status 
register) */
+        strh   \rt, [\rb, #STATUS_REG]                   /* Write status 
register */
 .endm
 
 /*
--
generated by git-patchbot for /home/xen/git/xen.git#staging

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