Re: [PATCH] staging: wilc1000: revert "fix TODO to compile spi and sdio components in single module"

[Ajay Singh]

Hi Arnd,

On Mon, 13 Aug 2018 23:20:33 +0200
Arnd Bergmann <arnd@xxxxxxxx> wrote:

> The TODO item named "make spi and sdio components coexist in one
> build" was apparently addressed a long time ago, but never removed
> from the TODO file. However, the new patch that tries to address it
> actually makes it worse again by duplicating the common parts of the
> driver into two separate modules rather than sharing them. This also
> introduces a build regression when one of the two is built-in while
> the other is a loadable module:

Thanks for sharing your inputs and submitting patch.
I have also submitted a patch to address the compilation error[1].
We can ignore my patch and proceed with your changes.

[1].https://patchwork.kernel.org/patch/10563873/

In my understanding, even when the common part is compiled separately,
the wilc1000-sdio/wilc1000-spi module still expects separate instance of
common part for each of them because of use of static variables.

Shouldn't it be correct to compile the components required for SDIO and
SPI separately and then get rid of use of global variables to support
running of SDIO/SPI module at same time?

> 
> drivers/staging/wilc1000/wilc_debugfs.o:(.data+0x10): undefined
> reference to `__this_module'
> 
> Reverting the patch makes it build again. I'm leaving the TODO file
> modification though, as there is nothing left to do for this item.
> 
> A related problem however still seems to exist: one still cannot have
> multiple concurrent instances of wilc1000 devices present in the
> system, as there are lots of shared global variables such as
> 
> host_interface.c:static struct wilc_vif *periodic_rssi_vif;
> wilc_sdio.c:static struct wilc_sdio g_sdio;
> wilc_wlan.c:static enum chip_ps_states chip_ps_state = CHIP_WAKEDUP;
> wilc_wlan.c:static u32 pending_acks;
> wilc_wfi_cfgoperations.c:int wilc_connecting;
> 
> In order to have multiple instances working (sdio, spi, or mixed),
> all such variables need to be dynamically allocated per instance and
> stored in 'struct wilc' or one of the structures referenced by it.
> 

Actually, I have been locally working on this patch for a while now
and I will submit a patch to avoid use of most of global and static
variable soon. 

> Fixes: 9abc44ba4e2f ("staging: wilc1000: fix TODO to compile spi and
> sdio components in single module") Signed-off-by: Arnd Bergmann
> <arnd@xxxxxxxx> ---
>  drivers/staging/wilc1000/Makefile       | 3 +--
>  drivers/staging/wilc1000/linux_wlan.c   | 6 ++++--
>  drivers/staging/wilc1000/wilc_debugfs.c | 7 +++++--
>  drivers/staging/wilc1000/wilc_wlan.c    | 6 ++++++
>  drivers/staging/wilc1000/wilc_wlan_if.h | 2 --
>  5 files changed, 16 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/staging/wilc1000/Makefile
> b/drivers/staging/wilc1000/Makefile index f7b07c0b5ce2..ee7e26b886a5
> 100644 --- a/drivers/staging/wilc1000/Makefile
> +++ b/drivers/staging/wilc1000/Makefile
> @@ -1,4 +1,5 @@
>  # SPDX-License-Identifier: GPL-2.0
> +obj-$(CONFIG_WILC1000) += wilc1000.o
>  
>  ccflags-y += -DFIRMWARE_1002=\"atmel/wilc1002_firmware.bin\" \
>  		-DFIRMWARE_1003=\"atmel/wilc1003_firmware.bin\"
> @@ -11,9 +12,7 @@ wilc1000-objs := wilc_wfi_cfgoperations.o
> linux_wlan.o linux_mon.o \ wilc_wlan.o
>  
>  obj-$(CONFIG_WILC1000_SDIO) += wilc1000-sdio.o
> -wilc1000-sdio-objs += $(wilc1000-objs)
>  wilc1000-sdio-objs += wilc_sdio.o
>  
>  obj-$(CONFIG_WILC1000_SPI) += wilc1000-spi.o
> -wilc1000-spi-objs += $(wilc1000-objs)
>  wilc1000-spi-objs += wilc_spi.o
> diff --git a/drivers/staging/wilc1000/linux_wlan.c
> b/drivers/staging/wilc1000/linux_wlan.c index
> 01cf4bd2e192..3b8d237decbf 100644 ---
> a/drivers/staging/wilc1000/linux_wlan.c +++
> b/drivers/staging/wilc1000/linux_wlan.c @@ -1038,8 +1038,8 @@ void
> wilc_netdev_cleanup(struct wilc *wilc) }
>  
>  	kfree(wilc);
> -	wilc_debugfs_remove();
>  }
> +EXPORT_SYMBOL_GPL(wilc_netdev_cleanup);
>  
>  static const struct net_device_ops wilc_netdev_ops = {
>  	.ndo_init = mac_init_fn,
> @@ -1062,7 +1062,6 @@ int wilc_netdev_init(struct wilc **wilc, struct
> device *dev, int io_type, if (!wl)
>  		return -ENOMEM;
>  
> -	wilc_debugfs_init();
>  	*wilc = wl;
>  	wl->io_type = io_type;
>  	wl->hif_func = ops;
> @@ -1124,3 +1123,6 @@ int wilc_netdev_init(struct wilc **wilc, struct
> device *dev, int io_type, 
>  	return 0;
>  }
> +EXPORT_SYMBOL_GPL(wilc_netdev_init);
> +
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/staging/wilc1000/wilc_debugfs.c
> b/drivers/staging/wilc1000/wilc_debugfs.c index
> edc72876458d..8001df66b8c2 100644 ---
> a/drivers/staging/wilc1000/wilc_debugfs.c +++
> b/drivers/staging/wilc1000/wilc_debugfs.c @@ -19,6 +19,7 @@ static
> struct dentry *wilc_dir; 
>  #define DBG_LEVEL_ALL	(DEBUG | INFO | WRN | ERR)
>  static atomic_t WILC_DEBUG_LEVEL = ATOMIC_INIT(ERR);
> +EXPORT_SYMBOL_GPL(WILC_DEBUG_LEVEL);
>  
>  static ssize_t wilc_debug_level_read(struct file *file, char __user
> *userbuf, size_t count, loff_t *ppos)
> @@ -87,7 +88,7 @@ static struct wilc_debugfs_info_t debugfs_info[] = {
>  	},
>  };
>  
> -int wilc_debugfs_init(void)
> +static int __init wilc_debugfs_init(void)
>  {
>  	int i;
>  	struct wilc_debugfs_info_t *info;
> @@ -103,10 +104,12 @@ int wilc_debugfs_init(void)
>  	}
>  	return 0;
>  }
> +module_init(wilc_debugfs_init);
>  
> -void wilc_debugfs_remove(void)
> +static void __exit wilc_debugfs_remove(void)
>  {
>  	debugfs_remove_recursive(wilc_dir);
>  }
> +module_exit(wilc_debugfs_remove);
>  
>  #endif
> diff --git a/drivers/staging/wilc1000/wilc_wlan.c
> b/drivers/staging/wilc1000/wilc_wlan.c index
> 6787b6e9f124..8b184aa30d25 100644 ---
> a/drivers/staging/wilc1000/wilc_wlan.c +++
> b/drivers/staging/wilc1000/wilc_wlan.c @@ -417,6 +417,7 @@ void
> chip_allow_sleep(struct wilc *wilc)
> wilc->hif_func->hif_write_reg(wilc, 0xf0, reg & ~BIT(0));
> wilc->hif_func->hif_write_reg(wilc, 0xfa, 0); }
> +EXPORT_SYMBOL_GPL(chip_allow_sleep);
>  
>  void chip_wakeup(struct wilc *wilc)
>  {
> @@ -471,6 +472,7 @@ void chip_wakeup(struct wilc *wilc)
>  	}
>  	chip_ps_state = CHIP_WAKEDUP;
>  }
> +EXPORT_SYMBOL_GPL(chip_wakeup);
>  
>  void wilc_chip_sleep_manually(struct wilc *wilc)
>  {
> @@ -484,6 +486,7 @@ void wilc_chip_sleep_manually(struct wilc *wilc)
>  	chip_ps_state = CHIP_SLEEPING_MANUAL;
>  	release_bus(wilc, RELEASE_ONLY);
>  }
> +EXPORT_SYMBOL_GPL(wilc_chip_sleep_manually);
>  
>  void host_wakeup_notify(struct wilc *wilc)
>  {
> @@ -491,6 +494,7 @@ void host_wakeup_notify(struct wilc *wilc)
>  	wilc->hif_func->hif_write_reg(wilc, 0x10b0, 1);
>  	release_bus(wilc, RELEASE_ONLY);
>  }
> +EXPORT_SYMBOL_GPL(host_wakeup_notify);
>  
>  void host_sleep_notify(struct wilc *wilc)
>  {
> @@ -498,6 +502,7 @@ void host_sleep_notify(struct wilc *wilc)
>  	wilc->hif_func->hif_write_reg(wilc, 0x10ac, 1);
>  	release_bus(wilc, RELEASE_ONLY);
>  }
> +EXPORT_SYMBOL_GPL(host_sleep_notify);
>  
>  int wilc_wlan_handle_txq(struct net_device *dev, u32 *txq_count)
>  {
> @@ -871,6 +876,7 @@ void wilc_handle_isr(struct wilc *wilc)
>  
>  	release_bus(wilc, RELEASE_ALLOW_SLEEP);
>  }
> +EXPORT_SYMBOL_GPL(wilc_handle_isr);
>  
>  int wilc_wlan_firmware_download(struct wilc *wilc, const u8 *buffer,
>  				u32 buffer_size)
> diff --git a/drivers/staging/wilc1000/wilc_wlan_if.h
> b/drivers/staging/wilc1000/wilc_wlan_if.h index
> 00d13b153f80..b81a73b9bd67 100644 ---
> a/drivers/staging/wilc1000/wilc_wlan_if.h +++
> b/drivers/staging/wilc1000/wilc_wlan_if.h @@ -831,6 +831,4 @@ struct
> wilc; int wilc_wlan_init(struct net_device *dev);
>  u32 wilc_get_chipid(struct wilc *wilc, bool update);
>  
> -int wilc_debugfs_init(void);
> -void wilc_debugfs_remove(void);
>  #endif