diff mbox series

[V4,4/5] xen/arm: Extend SCIF early prink code to handle other interfaces

Message ID 1555513175-7596-5-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State Superseded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 17, 2019, 2:59 p.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

        Changes in v4:
        - Update docs/misc/arm/early-printk.txt with the new option
---
 docs/misc/arm/early-printk.txt    |  6 ++++++
 xen/arch/arm/Rules.mk             |  7 +++++++
 xen/arch/arm/arm32/debug-scif.inc | 13 +++++++++----
 3 files changed, 22 insertions(+), 4 deletions(-)

Comments

Julien Grall April 29, 2019, 2:29 p.m. UTC | #1 
Hi Oleksandr,

On 17/04/2019 15:59, 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
> 
>          Changes in v4:
>          - Update docs/misc/arm/early-printk.txt with the new option
> ---
>   docs/misc/arm/early-printk.txt    |  6 ++++++
>   xen/arch/arm/Rules.mk             |  7 +++++++
>   xen/arch/arm/arm32/debug-scif.inc | 13 +++++++++----
>   3 files changed, 22 insertions(+), 4 deletions(-)
> 
> diff --git a/docs/misc/arm/early-printk.txt b/docs/misc/arm/early-printk.txt
> index b23c54f..c054674 100644
> --- a/docs/misc/arm/early-printk.txt
> +++ b/docs/misc/arm/early-printk.txt
> @@ -27,6 +27,12 @@ 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>
> +    - <VERSION> is a option to choose which interface version should be used

By "a option" did you intend to mean it is an optional parameter?

If so, how about:

"SCIF<VERSION> is, optionally, the interface version of the UART."

So you would also provide a way for the user to know how to specify it. Stefano 
any opinion?

> +      If <VERSION> is not given then a default interface version (SCIF)

s/a/the/

> +      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 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
>   
>   /*
> 

CHeers,
Oleksandr Tyshchenko April 30, 2019, 11 a.m. UTC | #2 
On 29.04.19 17:29, Julien Grall wrote:
> Hi Oleksandr,

Hi Julien


>
>> ---
>>   docs/misc/arm/early-printk.txt    |  6 ++++++
>>   xen/arch/arm/Rules.mk             |  7 +++++++
>>   xen/arch/arm/arm32/debug-scif.inc | 13 +++++++++----
>>   3 files changed, 22 insertions(+), 4 deletions(-)
>>
>> diff --git a/docs/misc/arm/early-printk.txt 
>> b/docs/misc/arm/early-printk.txt
>> index b23c54f..c054674 100644
>> --- a/docs/misc/arm/early-printk.txt
>> +++ b/docs/misc/arm/early-printk.txt
>> @@ -27,6 +27,12 @@ 
>> 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>
>> +    - <VERSION> is a option to choose which interface version should 
>> be used
>
> By "a option" did you intend to mean it is an optional parameter?
>
> If so, how about:
>
> "SCIF<VERSION> is, optionally, the interface version of the UART."

agree. will change.


>
> So you would also provide a way for the user to know how to specify 
> it. Stefano any opinion?

I am going to update Wiki page regarding how to run Stout board on Xen 
and how to properly enable earlyprintk support on that board.

Would it be enough? Also I can add a note to patch description.

In V1 I added convenient alias EARLY_PRINTK_stout, but AFAIR it was 
decided to avoid adding new aliases.


>
>> +      If <VERSION> is not given then a default interface version (SCIF)
>
> s/a/the/

ok
Julien Grall May 7, 2019, 3:58 p.m. UTC | #3 
Hi,

On 4/30/19 12:00 PM, Oleksandr wrote:
> 
> On 29.04.19 17:29, Julien Grall wrote:
>> Hi Oleksandr,
> 
> Hi Julien
> 
> 
>>
>>> ---
>>>   docs/misc/arm/early-printk.txt    |  6 ++++++
>>>   xen/arch/arm/Rules.mk             |  7 +++++++
>>>   xen/arch/arm/arm32/debug-scif.inc | 13 +++++++++----
>>>   3 files changed, 22 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/docs/misc/arm/early-printk.txt 
>>> b/docs/misc/arm/early-printk.txt
>>> index b23c54f..c054674 100644
>>> --- a/docs/misc/arm/early-printk.txt
>>> +++ b/docs/misc/arm/early-printk.txt
>>> @@ -27,6 +27,12 @@ 
>>> 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>
>>> +    - <VERSION> is a option to choose which interface version should 
>>> be used
>>
>> By "a option" did you intend to mean it is an optional parameter?
>>
>> If so, how about:
>>
>> "SCIF<VERSION> is, optionally, the interface version of the UART."
> 
> agree. will change.
> 
> 
>>
>> So you would also provide a way for the user to know how to specify 
>> it. Stefano any opinion?
> 
> I am going to update Wiki page regarding how to run Stout board on Xen 
> and how to properly enable earlyprintk support on that board.

My point was not adding new alias (I am not in favor anyway), but giving 
hint to the user how infer the value of <VERSION>.

The wiki page for the board can then explain a bit more into details how 
to setup earlyprintk.

Cheers,
diff mbox series

Patch

diff --git a/docs/misc/arm/early-printk.txt b/docs/misc/arm/early-printk.txt
index b23c54f..c054674 100644
--- a/docs/misc/arm/early-printk.txt
+++ b/docs/misc/arm/early-printk.txt
@@ -27,6 +27,12 @@  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>
+    - <VERSION> is a option to choose which interface version should be used
+      on a target board.
+
+      If <VERSION> is not given then a 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 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
 
 /*