Re: [PATCH v3,5/5] powerpc: sysdev: support userspace access of fsl_85xx_sram
From: çæè
Date: Fri Apr 24 2020 - 03:05:20 EST
>Le 24/04/2020 Ã 04:45, Wang Wenhu a ÃcritÂ:
>> New module which registers its memory allocation and free APIs to the
>> sram_dynamic module, which would create a device of struct sram_device
>> type to act as an interface for user level applications to access the
>> backend hardware device, fsl_85xx_cache_sram, which is drived by the
>> FSL_85XX_CACHE_SRAM module.
>>
>> Signed-off-by: Wang Wenhu <wenhu.wang@xxxxxxxx>
>> Cc: Christophe Leroy <christophe.leroy@xxxxxx>
>> Cc: Scott Wood <oss@xxxxxxxxxxxx>
>> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
>> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
>> Cc: Arnd Bergmann <arnd@xxxxxxxx>
>> Cc: linuxppc-dev@xxxxxxxxxxxxxxxx
>> ---
>> .../powerpc/include/asm/fsl_85xx_cache_sram.h | 4 ++
>> arch/powerpc/platforms/85xx/Kconfig | 10 +++++
>> arch/powerpc/sysdev/Makefile | 1 +
>> arch/powerpc/sysdev/fsl_85xx_cache_ctlr.h | 6 +++
>> arch/powerpc/sysdev/fsl_85xx_cache_sram.c | 12 ++++++
>> arch/powerpc/sysdev/fsl_85xx_sram_uapi.c | 39 +++++++++++++++++++
>> 6 files changed, 72 insertions(+)
>> create mode 100644 arch/powerpc/sysdev/fsl_85xx_sram_uapi.c
>
>We shouldn't add more stuff in arch/powerpc/sysdev/
>
>Either it is dedicated to 85xx, and it should go into
>arch/powerpc/platform/85xx/ , or it is common to several
>platforms/architectures and should be moved to drivers/soc/fsl/
>
Sure, actually I tried to find a better place, but did not recognize
the driver/soc. Thanks, and I will put fsl_85xx_sram_uapi there.
>>
>> diff --git a/arch/powerpc/include/asm/fsl_85xx_cache_sram.h b/arch/powerpc/include/asm/fsl_85xx_cache_sram.h
>> index 0235a0447baa..99cb7e202c38 100644
>> --- a/arch/powerpc/include/asm/fsl_85xx_cache_sram.h
>> +++ b/arch/powerpc/include/asm/fsl_85xx_cache_sram.h
>> @@ -26,6 +26,10 @@ struct mpc85xx_cache_sram {
>> unsigned int size;
>> rh_info_t *rh;
>> spinlock_t lock;
>> +
>> +#ifdef CONFIG_FSL_85XX_SRAM_UAPI
>> + struct device *dev;
>> +#endif
>> };
>>
>> extern void mpc85xx_cache_sram_free(void *ptr);
>> diff --git a/arch/powerpc/platforms/85xx/Kconfig b/arch/powerpc/platforms/85xx/Kconfig
>> index fa3d29dcb57e..3a6f6af973eb 100644
>> --- a/arch/powerpc/platforms/85xx/Kconfig
>> +++ b/arch/powerpc/platforms/85xx/Kconfig
>> @@ -16,6 +16,16 @@ if FSL_SOC_BOOKE
>>
>> if PPC32
>>
>> +config FSL_85XX_SRAM_UAPI
>> + tristate "Freescale MPC85xx SRAM UAPI Support"
>> + depends on FSL_SOC_BOOKE && SRAM_DYNAMIC
>
>Is SRAM_DYNAMIC usefull on its own, without a driver like this one ? Is
>that worth allowing tiny selection of both drivers ? Shouldn't one of
>them imply the other one ?
Truely the module like this is the top level selection, and SRAM_DYNAMIC
should be selected by any caller modules. As SRAM_DYNAMIC may be used by
other drivers(in the future, but currently only us here), I think make it
seleted by this is better? (show below)
diff --git a/drivers/soc/fsl/Kconfig b/drivers/soc/fsl/Kconfig
index 4df32bc4c7a6..ceeebb22f6d3 100644
--- a/drivers/soc/fsl/Kconfig
+++ b/drivers/soc/fsl/Kconfig
@@ -50,4 +50,16 @@ config FSL_RCPM
tasks associated with power management, such as wakeup source control.
Note that currently this driver will not support PowerPC based
QorIQ processor.
+
+config FSL_85XX_SRAM_UAPI
+ tristate "Freescale MPC85xx SRAM UAPI Support"
+ depends on FSL_SOC_BOOKE && PPC32
+ select FSL_85XX_CACHE_SRAM
+ select SRAM_DYNAMIC
+ help
+ This registers a device of struct sram_device type which would act as
+ an interface for user level applications to access the Freescale 85xx
+ Cache-SRAM memory dynamically, meaning allocate on demand dynamically
+ while they are running.
+
endmenu
diff --git a/drivers/soc/fsl/Makefile b/drivers/soc/fsl/Makefile
index 906f1cd8af01..716e38f75735 100644
--- a/drivers/soc/fsl/Makefile
+++ b/drivers/soc/fsl/Makefile
@@ -10,3 +10,4 @@ obj-$(CONFIG_FSL_RCPM) += rcpm.o
obj-$(CONFIG_FSL_GUTS) += guts.o
obj-$(CONFIG_FSL_MC_DPIO) += dpio/
obj-$(CONFIG_DPAA2_CONSOLE) += dpaa2-console.o
+obj-$(CONFIG_FSL_85XX_SRAM_UAPI) += fsl_85xx_sram_uapi.o
>>
>> +#ifdef CONFIG_FSL_85XX_SRAM_UAPI
>> +extern struct mpc85xx_cache_sram *mpc85xx_get_cache_sram(void);
>
>'extern' keywork is meaningless here, remove it.
>
I will remove it in patch v4.
>> +#endif
>> +
>> extern int instantiate_cache_sram(struct platform_device *dev,
>> struct sram_parameters sram_params);
>> extern void remove_cache_sram(struct platform_device *dev);
>> diff --git a/arch/powerpc/sysdev/fsl_85xx_cache_sram.c b/arch/powerpc/sysdev/fsl_85xx_cache_sram.c
>> index 3de5ac8382c0..0156ea63a3a2 100644
>> --- a/arch/powerpc/sysdev/fsl_85xx_cache_sram.c
>> +++ b/arch/powerpc/sysdev/fsl_85xx_cache_sram.c
>> @@ -23,6 +23,14 @@
>>
>> struct mpc85xx_cache_sram *cache_sram;
>>
>> +
>> +#ifdef CONFIG_FSL_85XX_SRAM_UAPI
>> +struct mpc85xx_cache_sram *mpc85xx_get_cache_sram(void)
>> +{
>> + return cache_sram;
>> +}
>> +#endif
>
>This function is not worth the mess of an #ifdef in a .c file.
>cache_sram is already globaly visible, so this function should go in
>fsl_85xx_cache_ctlr.h as a 'static inline'
>
Yes, and I will change it like this, with an extern of cache_sram.
#define L2CR_SRAM_ZERO 0x00000000 /* L2SRAM zero size */
@@ -81,6 +83,15 @@ struct sram_parameters {
phys_addr_t sram_offset;
};
+#ifdef CONFIG_FSL_85XX_SRAM_UAPI
+extern struct mpc85xx_cache_sram *cache_sram;
+
+static inline struct mpc85xx_cache_sram *mpc85xx_get_cache_sram(void)
+{
+ return cache_sram;
+}
+#endif
+
extern int instantiate_cache_sram(struct platform_device *dev,
>> +
>> void *mpc85xx_cache_sram_alloc(unsigned int size,
>> phys_addr_t *phys, unsigned int align)
>> {
>> @@ -115,6 +123,10 @@ int instantiate_cache_sram(struct platform_device *dev,
>> rh_attach_region(cache_sram->rh, 0, cache_sram->size);
>> spin_lock_init(&cache_sram->lock);
>>
>> +#ifdef CONFIG_FSL_85XX_SRAM_UAPI
>> + cache_sram->dev = &dev->dev;
>> +#endif
>
> Can we avoid the #ifdef in .c file ? (see
>https://www.kernel.org/doc/html/latest/process/coding-style.html#conditional-compilation)
>
Definitely, and I will change it as below in patch v4:
+ if (IS_ENABLED(CONFIG_FSL_85XX_SRAM_UAPI))
+ cache_sram->dev = &dev->dev;
+
dev_info(&dev->dev, "[base:0x%llx, size:0x%x] configured and loaded\n",
Thanks, for your suggestions, as these are minor modifications,
I will send a new patch series v4 soon.
Regards,
Wenhu