diff mbox series

[V3,4/5] xen/arm: Extend SCIF early prink code to handle other interfaces

Message ID 1554718489-11318-5-git-send-email-olekstysh@gmail.com (mailing list archive)
State Superseded
Headers show
Series Renesas Stout board support (R-Car Gen2) | expand

Commit Message

Oleksandr Tyshchenko April 8, 2019, 10:14 a.m. UTC 
From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>

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@epam.com>
CC: Julien Grall <julien.grall@arm.com>

---
    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 reworks a code
---
 xen/arch/arm/Rules.mk             |  7 +++++++
 xen/arch/arm/arm32/debug-scif.inc | 13 +++++++++----
 2 files changed, 16 insertions(+), 4 deletions(-)

Comments

Julien Grall April 14, 2019, 5:48 p.m. UTC | #1 
Hi,

On 4/8/19 11:14 AM, Oleksandr Tyshchenko wrote:
> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
> 
> 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@epam.com>
> CC: Julien Grall <julien.grall@arm.com>
> 
> ---
>      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 reworks a code
> ---
>   xen/arch/arm/Rules.mk             |  7 +++++++
>   xen/arch/arm/arm32/debug-scif.inc | 13 +++++++++----

You want to update docs/misc/arm/early-printk.txt with the new option.

Otherwise, the code looks good to me.

Cheers,
Oleksandr Tyshchenko April 15, 2019, 11:38 a.m. UTC | #2 
On 14.04.19 20:48, Julien Grall wrote:
> Hi,

Hi Julien


>
> On 4/8/19 11:14 AM, Oleksandr Tyshchenko wrote:
>> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
>>
>> 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@epam.com>
>> CC: Julien Grall <julien.grall@arm.com>
>>
>> ---
>>      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 reworks a code
>> ---
>>   xen/arch/arm/Rules.mk             |  7 +++++++
>>   xen/arch/arm/arm32/debug-scif.inc | 13 +++++++++----
>
> You want to update docs/misc/arm/early-printk.txt with the new option.

Sure, will update.


>
> Otherwise, the code looks good to me.
>
> Cheers,
>
diff mbox series

Patch

diff --git a/xen/arch/arm/Rules.mk b/xen/arch/arm/Rules.mk
index f264592..3d9a0ed 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 143f05d..a8d2eae 100644
--- a/xen/arch/arm/arm32/debug-scif.inc
+++ b/xen/arch/arm/arm32/debug-scif.inc
@@ -19,6 +19,11 @@ 
 
 #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
  * rb: register which contains the UART base address
@@ -26,7 +31,7 @@ 
  */
 .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
@@ -37,10 +42,10 @@ 
  * 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
 
 /*