Re: [rtc-linux] Re: [RFC 15/15] mfd: syscon: Fix build of missing ioremap on UM

Krzysztof Kozlowski
2016-03-03T12:24:06Z

2016-03-03 19:50 GMT+09:00 Arnd Bergmann <arnd@arndb.de>:
> On Thursday 03 March 2016 17:03:41 Krzysztof Kozlowski wrote:
>> Since commit c89c0114955a ("mfd: syscon: Set regmap max_register in
>> of_syscon_register") the syscon uses ioremap so it fails on COMPILE_TEST
>> without HAS_IOMEM:
>>
>> drivers/mfd/syscon.c: In function ‘of_syscon_register’:
>> drivers/mfd/syscon.c:67:9: error: implicit declaration of function ‘ioremap’ [-Werror=implicit-function-declaration]
>> base = ioremap(res.start, resource_size(&res));
>> ^
>> drivers/mfd/syscon.c:67:7: warning: assignment makes pointer from integer without a cast [-Wint-conversion]
>> base = ioremap(res.start, resource_size(&res));
>> ^
>> drivers/mfd/syscon.c:109:2: error: implicit declaration of function ‘iounmap’ [-Werror=implicit-function-declaration]
>> iounmap(base);
>>
>> When selecting MFD_SYSCON, depend on HAS_IOMEM to avoid unmet direct
>> dependencies.
>>
>> Reported-by: kbuild test robot <lkp@intel.com>
>> Fixes: c89c0114955a ("mfd: syscon: Set regmap max_register in of_syscon_register")
>> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
>> ---
>
> Thanks for looking into this, the patches all look right to me, but
> I fear we are forever playing catch-up here, as the number of syscon users
> is only growing, and it's not obvious to the average driver developer
> why they have to select this symbol.

Actually I screwed something because entire MFD menuconfig (including
MFD_SYSCON) is already guarded by if HAS_IOMEM.

I was fixing the problem from the end (the build error) and then hit
these unmet direct dependencies (mentioned this in other mail).

I think this patch 15/15 is not needed.

>
> Interestingly, when I try to build an allmodconfig kernel for UML,
> it seems to reject any driver calling ioremap/iounmap but not
> the wrapper functions around that (of_iomap, devm_ioremap,
> devm_ioremap_resource, ...)

The declaration of devm-like functions is always there. However it
should fail during linking stage (see my other patches like for
thermal, nvram etc. this is still in progress because I did not manage
to build allyesconfig on UML yet).

> or the actual accessors that make no
> sense without ioremap (readl, writel, inb, outb, iowrite32, ...).
>
> I've played with this a bit, and arrived at the patch below, is this
> something we want as well?
>
> Arnd
>
>> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
>> index aa21dc55eb15..2e5b1e525a1d 100644
>> --- a/drivers/mfd/Kconfig
>> +++ b/drivers/mfd/Kconfig
>> @@ -1034,6 +1034,7 @@ config MFD_SUN6I_PRCM
>>
>> config MFD_SYSCON
>> bool "System Controller Register R/W Based on Regmap"
>> + depends on HAS_IOMEM
>> select REGMAP_MMIO
>> help
>> Select this option to enable accessing system control registers
>>
>
>
> arch/um/include/asm/io.h | 1 +
> drivers/char/Kconfig | 3 +++
> drivers/char/mem.c | 16 ++++++++++++++++
> drivers/clocksource/Kconfig | 3 +++
> drivers/fmc/Kconfig | 1 +
> drivers/fpga/Kconfig | 1 +
> drivers/hwtracing/intel_th/Kconfig | 1 +
> drivers/mfd/Kconfig | 1 +
> drivers/misc/altera-stapl/Kconfig | 2 +-
> drivers/mtd/chips/Kconfig | 4 ++++
> drivers/mtd/lpddr/Kconfig | 1 +
> drivers/mtd/maps/Kconfig | 3 ++-
> drivers/mtd/nand/Kconfig | 2 +-
> drivers/mtd/spi-nor/Kconfig | 1 +
> drivers/net/can/Kconfig | 1 +
> drivers/net/hamradio/Kconfig | 9 ++++++---
> drivers/nvmem/Kconfig | 1 +
> drivers/phy/Kconfig | 9 +++++++--
> drivers/power/reset/Kconfig | 4 +++-
> drivers/staging/comedi/Kconfig | 6 +++++-
> drivers/thermal/Kconfig | 11 +++++++++--

For some of these I already started fixing:
https://lkml.org/lkml/2016/3/3/147
http://comments.gmane.org/gmane.linux.kernel/2167664

> include/linux/irq.h | 2 ++
> include/linux/mtd/cfi.h | 2 ++
> include/linux/mtd/map.h | 2 ++
> kernel/resource.c | 2 ++
> lib/Kconfig | 7 ++++++-
> mm/bootmem.c | 4 ++--
> 27 files changed, 85 insertions(+), 15 deletions(-)
>
> diff --git a/arch/um/include/asm/io.h b/arch/um/include/asm/io.h
> new file mode 100644
> index 0000000..618ff13
> --- /dev/null
> +++ b/arch/um/include/asm/io.h
> @@ -0,0 +1 @@
> +/* no IOPORT or IOMEM suport */
> diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
> index a043107..f6dc17a 100644
> --- a/drivers/char/Kconfig
> +++ b/drivers/char/Kconfig
> @@ -8,6 +8,7 @@ source "drivers/tty/Kconfig"
>
> config DEVMEM
> bool "/dev/mem virtual device support"
> + depends on HAS_IOMEM
> default y
> help
> Say Y here if you want to support the /dev/mem device.
> @@ -17,6 +18,7 @@ config DEVMEM
>
> config DEVKMEM
> bool "/dev/kmem virtual device support"
> + depends on HAS_IOMEM
> default y
> help
> Say Y here if you want to support the /dev/kmem device. The
> @@ -94,6 +96,7 @@ config BFIN_OTP_WRITE_ENABLE
> config PRINTER
> tristate "Parallel printer support"
> depends on PARPORT
> + depends on HAS_IOPORT
> ---help---
> If you intend to attach a printer to the parallel port of your Linux
> box (as opposed to using a serial printer; if the connector at the
> diff --git a/drivers/char/mem.c b/drivers/char/mem.c
> index 4f6f94c..eedd129 100644
> --- a/drivers/char/mem.c
> +++ b/drivers/char/mem.c
> @@ -91,6 +91,7 @@ void __weak unxlate_dev_mem_ptr(phys_addr_t phys, void *addr)
> }
> #endif
>
> +#ifdef CONFIG_DEVMEM
> /*
> * This funcion reads the *physical* memory. The f_pos points directly to the
> * memory location.
> @@ -219,6 +220,7 @@ static ssize_t write_mem(struct file *file, const char __user *buf,
> *ppos += written;
> return written;
> }
> +#endif
>
> int __weak phys_mem_access_prot_allowed(struct file *file,
> unsigned long pfn, unsigned long size, pgprot_t *vma_prot)
> @@ -312,6 +314,7 @@ static inline int private_mapping_ok(struct vm_area_struct *vma)
> }
> #endif
>
> +#ifdef CONFIG_DEVMEM
> static const struct vm_operations_struct mmap_mem_ops = {
> #ifdef CONFIG_HAVE_IOREMAP_PROT
> .access = generic_access_phys
> @@ -351,7 +354,9 @@ static int mmap_mem(struct file *file, struct vm_area_struct *vma)
> }
> return 0;
> }
> +#endif
>
> +#ifdef CONFIG_DEVKMEM
> static int mmap_kmem(struct file *file, struct vm_area_struct *vma)
> {
> unsigned long pfn;
> @@ -552,7 +557,9 @@ static ssize_t write_kmem(struct file *file, const char __user *buf,
> *ppos = p;
> return virtr + wrote ? : err;
> }
> +#endif
>
> +#ifdef CONFIG_DEVPORT
> static ssize_t read_port(struct file *file, char __user *buf,
> size_t count, loff_t *ppos)
> {
> @@ -594,6 +601,7 @@ static ssize_t write_port(struct file *file, const char __user *buf,
> *ppos = i;
> return tmp-buf;
> }
> +#endif
>
> static ssize_t read_null(struct file *file, char __user *buf,
> size_t count, loff_t *ppos)
> @@ -710,10 +718,12 @@ static loff_t memory_lseek(struct file *file, loff_t offset, int orig)
> return ret;
> }
>
> +#ifdef CONFIG_DEVPORT
> static int open_port(struct inode *inode, struct file *filp)
> {
> return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
> }
> +#endif
>
> #define zero_lseek null_lseek
> #define full_lseek null_lseek
> @@ -722,6 +732,7 @@ static int open_port(struct inode *inode, struct file *filp)
> #define open_mem open_port
> #define open_kmem open_mem
>
> +#ifdef CONFIG_DEVMEM
> static const struct file_operations __maybe_unused mem_fops = {
> .llseek = memory_lseek,
> .read = read_mem,
> @@ -733,7 +744,9 @@ static const struct file_operations __maybe_unused mem_fops = {
> .mmap_capabilities = memory_mmap_capabilities,
> #endif
> };
> +#endif
>
> +#ifdef CONFIG_DEVKMEM
> static const struct file_operations __maybe_unused kmem_fops = {
> .llseek = memory_lseek,
> .read = read_kmem,
> @@ -745,6 +758,7 @@ static const struct file_operations __maybe_unused kmem_fops = {
> .mmap_capabilities = memory_mmap_capabilities,
> #endif
> };
> +#endif
>
> static const struct file_operations null_fops = {
> .llseek = null_lseek,
> @@ -755,12 +769,14 @@ static const struct file_operations null_fops = {
> .splice_write = splice_write_null,
> };
>
> +#ifdef CONFIG_DEVPORT
> static const struct file_operations __maybe_unused port_fops = {
> .llseek = memory_lseek,
> .read = read_port,
> .write = write_port,
> .open = open_port,
> };
> +#endif
>
> static const struct file_operations zero_fops = {
> .llseek = zero_lseek,
> diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
> index 33db740..6b58974 100644
> --- a/drivers/clocksource/Kconfig
> +++ b/drivers/clocksource/Kconfig
> @@ -38,6 +38,7 @@ config DIGICOLOR_TIMER
> config DW_APB_TIMER
> bool "DW APB timer driver" if COMPILE_TEST
> depends on GENERIC_CLOCKEVENTS
> + depends on HAS_IOMEM
> help
> Enables the support for the dw_apb timer.
>
> @@ -64,6 +65,7 @@ config ARMADA_370_XP_TIMER
> config MESON6_TIMER
> bool "Meson6 timer driver" if COMPILE_TEST
> depends on GENERIC_CLOCKEVENTS
> + depends on HAS_IOMEM
> select CLKSRC_MMIO
> help
> Enables the support for the Meson6 timer driver.
> @@ -114,6 +116,7 @@ config CADENCE_TTC_TIMER
> config ASM9260_TIMER
> bool "ASM9260 timer driver" if COMPILE_TEST
> depends on GENERIC_CLOCKEVENTS
> + depends on HAS_IOMEM
> select CLKSRC_MMIO
> select CLKSRC_OF
> help
> diff --git a/drivers/fmc/Kconfig b/drivers/fmc/Kconfig
> index 3a75f42..adf1391 100644
> --- a/drivers/fmc/Kconfig
> +++ b/drivers/fmc/Kconfig
> @@ -4,6 +4,7 @@
>
> menuconfig FMC
> tristate "FMC support"
> + depends on HAS_IOMEM
> help
>
> FMC (FPGA Mezzanine Carrier) is a mechanical and electrical
> diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
> index c9b9fdf..36c54af 100644
> --- a/drivers/fpga/Kconfig
> +++ b/drivers/fpga/Kconfig
> @@ -21,6 +21,7 @@ config FPGA_MGR_SOCFPGA
>
> config FPGA_MGR_ZYNQ_FPGA
> tristate "Xilinx Zynq FPGA"
> + depends on HAS_IOMEM
> help
> FPGA manager driver support for Xilinx Zynq FPGAs.
>
> diff --git a/drivers/hwtracing/intel_th/Kconfig b/drivers/hwtracing/intel_th/Kconfig
> index b7a9073..467dae9 100644
> --- a/drivers/hwtracing/intel_th/Kconfig
> +++ b/drivers/hwtracing/intel_th/Kconfig
> @@ -1,5 +1,6 @@
> config INTEL_TH
> tristate "Intel(R) Trace Hub controller"
> + depends on HAS_IOMEM
> help
> Intel(R) Trace Hub (TH) is a set of hardware blocks (subdevices) that
> produce, switch and output trace data from multiple hardware and
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 9ca66de..6ff6246 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -999,6 +999,7 @@ config MFD_SUN6I_PRCM
>
> config MFD_SYSCON
> bool "System Controller Register R/W Based on Regmap"
> + depends on HAS_IOMEM

This shouldn't be needed. There is if HAS_IOMEM at beginning.

Best regards,
Krzysztof
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