Re: Increasing build coverage for drivers/spi/spi-ppc4xx.c

[Christophe Leroy <christophe.leroy@xxxxxxxxxx>]

Le 27/02/2024 à 09:46, Uwe Kleine-König a écrit :
> Hello,
> 
> recently the spi-ppc4xx.c driver suffered from build errors and warnings
> that were undetected for longer than I expected. I think it would be
> very beneficial if this driver was enabled in (at least) a powerpc
> allmodconfig build.
> 
> The challenge to do so is that spi-ppc4xx.c uses dcri_clrset() which is
> only defined for 4xx (as these select PPC_DCR_NATIVE).
> 
> I wonder if dcri_clrset() could be defined for the PPC_DCR_MMIO case,
> too. I tried and failed. The best I came up without extensive doc
> reading is:
> 
> diff --git a/arch/powerpc/include/asm/dcr-native.h b/arch/powerpc/include/asm/dcr-native.h
> index a92059964579..159ab7abfe46 100644
> --- a/arch/powerpc/include/asm/dcr-native.h
> +++ b/arch/powerpc/include/asm/dcr-native.h
> @@ -115,15 +115,11 @@ static inline void __dcri_clrset(int base_addr, int base_data, int reg,
>   	unsigned int val;
>   
>   	spin_lock_irqsave(&dcr_ind_lock, flags);
> -	if (cpu_has_feature(CPU_FTR_INDEXED_DCR)) {
> -		mtdcrx(base_addr, reg);
> -		val = (mfdcrx(base_data) & ~clr) | set;
> -		mtdcrx(base_data, val);
> -	} else {
> -		__mtdcr(base_addr, reg);
> -		val = (__mfdcr(base_data) & ~clr) | set;
> -		__mtdcr(base_data, val);
> -	}
> +
> +	mtdcr(base_addr, reg);
> +	val = (mfdcr(base_data) & ~clr) | set;
> +	mtdcr(base_data, val);
> +
>   	spin_unlock_irqrestore(&dcr_ind_lock, flags);
>   }
>   
> diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
> index bc7021da2fe9..9a0a5e8c70c8 100644
> --- a/drivers/spi/Kconfig
> +++ b/drivers/spi/Kconfig
> @@ -810,7 +810,8 @@ config SPI_PL022
>   
>   config SPI_PPC4xx
>   	tristate "PPC4xx SPI Controller"
> -	depends on PPC32 && 4xx
> +	depends on 4xx || COMPILE_TEST
> +	depends on PPC32 || PPC64
>   	select SPI_BITBANG
>   	help
>   	  This selects a driver for the PPC4xx SPI Controller.
> 
> While this is a step in the right direction (I think) it's not enough to
> make the driver build (but maybe make it easier to define
> dcri_clrset()?)
> 
> Could someone with more powerpc knowledge jump in and help (for the
> benefit of better compile coverage of the spi driver and so less
> breakage)? (If you do so based on my changes above, you don't need to
> credit me for my effort, claim it as your's. I'm happy enough if the
> situation improves.)

What about this ?

diff --git a/arch/powerpc/include/asm/dcr-mmio.h 
b/arch/powerpc/include/asm/dcr-mmio.h
index fc6d93ef4a13..38b515afbffc 100644
--- a/arch/powerpc/include/asm/dcr-mmio.h
+++ b/arch/powerpc/include/asm/dcr-mmio.h
@@ -38,6 +38,11 @@ static inline void dcr_write_mmio(dcr_host_mmio_t host,
  	out_be32(host.token + ((host.base + dcr_n) * host.stride), value);
  }

+static inline void __dcri_clrset(int base_addr, int base_data, int reg,
+				 unsigned clr, unsigned set)
+{
+}
+
  #endif /* __KERNEL__ */
  #endif /* _ASM_POWERPC_DCR_MMIO_H */

diff --git a/arch/powerpc/include/asm/dcr-native.h 
b/arch/powerpc/include/asm/dcr-native.h
index a92059964579..2f6221bf5406 100644
--- a/arch/powerpc/include/asm/dcr-native.h
+++ b/arch/powerpc/include/asm/dcr-native.h
@@ -135,10 +135,6 @@ static inline void __dcri_clrset(int base_addr, int 
base_data, int reg,
  					 DCRN_ ## base ## _CONFIG_DATA,	\
  					 reg, data)

-#define dcri_clrset(base, reg, clr, set)	__dcri_clrset(DCRN_ ## base ## 
_CONFIG_ADDR,	\
-							      DCRN_ ## base ## _CONFIG_DATA,	\
-							      reg, clr, set)
-
  #endif /* __ASSEMBLY__ */
  #endif /* __KERNEL__ */
  #endif /* _ASM_POWERPC_DCR_NATIVE_H */
diff --git a/arch/powerpc/include/asm/dcr.h b/arch/powerpc/include/asm/dcr.h
index 64030e3a1f30..15c123ae38a1 100644
--- a/arch/powerpc/include/asm/dcr.h
+++ b/arch/powerpc/include/asm/dcr.h
@@ -18,6 +18,9 @@
  #include <asm/dcr-mmio.h>
  #endif

+#define dcri_clrset(base, reg, clr, set)	__dcri_clrset(DCRN_ ## base ## 
_CONFIG_ADDR,	\
+							      DCRN_ ## base ## _CONFIG_DATA,	\
+							      reg, clr, set)

  /* Indirection layer for providing both NATIVE and MMIO support. */

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index ddae0fde798e..7b003c5dd613 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -810,7 +810,7 @@ config SPI_PL022

  config SPI_PPC4xx
  	tristate "PPC4xx SPI Controller"
-	depends on PPC32 && 4xx
+	depends on PPC && (4xx || COMPILE_TEST)
  	select SPI_BITBANG
  	help
  	  This selects a driver for the PPC4xx SPI Controller.