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Subject: Re: [PATCH v1 3/4] powerpc: Add support for GENERIC_EARLY_IOREMAP
To:     "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>, npiggin@gmail.com,
        hch@infradead.org
Cc:     linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
References: <cover.1568295907.git.christophe.leroy@c-s.fr>
 <412c7eaa6a373d8f82a3c3ee01e6a65a1a6589de.1568295907.git.christophe.leroy@c-s.fr>
 <87ftl1seyr.fsf@linux.ibm.com>
From:   Christophe Leroy <christophe.leroy@c-s.fr>
Message-ID: <cab82255-7353-1435-08cb-6732d429b17d@c-s.fr>
Date:   Thu, 12 Sep 2019 17:43:05 +0200
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Le 12/09/2019 à 17:37, Aneesh Kumar K.V a écrit :
> Christophe Leroy <christophe.leroy@c-s.fr> writes:
> 
>> Add support for GENERIC_EARLY_IOREMAP.
>>
>> Let's define 16 slots of 256Kbytes each for early ioremap.
>>
>> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
>> ---
>>   arch/powerpc/Kconfig              |  1 +
>>   arch/powerpc/include/asm/Kbuild   |  1 +
>>   arch/powerpc/include/asm/fixmap.h | 12 ++++++++++++
>>   arch/powerpc/kernel/setup_32.c    |  3 +++
>>   arch/powerpc/kernel/setup_64.c    |  3 +++
>>   5 files changed, 20 insertions(+)
>>
>> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
>> index 6a7c797fa9d2..8fe252962518 100644
>> --- a/arch/powerpc/Kconfig
>> +++ b/arch/powerpc/Kconfig
>> @@ -161,6 +161,7 @@ config PPC
>>   	select GENERIC_CMOS_UPDATE
>>   	select GENERIC_CPU_AUTOPROBE
>>   	select GENERIC_CPU_VULNERABILITIES	if PPC_BARRIER_NOSPEC
>> +	select GENERIC_EARLY_IOREMAP
>>   	select GENERIC_IRQ_SHOW
>>   	select GENERIC_IRQ_SHOW_LEVEL
>>   	select GENERIC_PCI_IOMAP		if PCI
>> diff --git a/arch/powerpc/include/asm/Kbuild b/arch/powerpc/include/asm/Kbuild
>> index 9a1d2fc6ceb7..30829120659c 100644
>> --- a/arch/powerpc/include/asm/Kbuild
>> +++ b/arch/powerpc/include/asm/Kbuild
>> @@ -12,3 +12,4 @@ generic-y += preempt.h
>>   generic-y += vtime.h
>>   generic-y += msi.h
>>   generic-y += simd.h
>> +generic-y += early_ioremap.h
>> diff --git a/arch/powerpc/include/asm/fixmap.h b/arch/powerpc/include/asm/fixmap.h
>> index 722289a1d000..d5c4d357bd33 100644
>> --- a/arch/powerpc/include/asm/fixmap.h
>> +++ b/arch/powerpc/include/asm/fixmap.h
>> @@ -15,6 +15,7 @@
>>   #define _ASM_FIXMAP_H
>>   
>>   #ifndef __ASSEMBLY__
>> +#include <linux/sizes.h>
>>   #include <asm/page.h>
>>   #include <asm/pgtable.h>
>>   #ifdef CONFIG_HIGHMEM
>> @@ -64,6 +65,14 @@ enum fixed_addresses {
>>   		       FIX_IMMR_SIZE,
>>   #endif
>>   	/* FIX_PCIE_MCFG, */
>> +	__end_of_permanent_fixed_addresses,
>> +
>> +#define NR_FIX_BTMAPS		(SZ_256K / PAGE_SIZE)
>> +#define FIX_BTMAPS_SLOTS	16
>> +#define TOTAL_FIX_BTMAPS	(NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
>> +
>> +	FIX_BTMAP_END = __end_of_permanent_fixed_addresses,
>> +	FIX_BTMAP_BEGIN = FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1,
>>   	__end_of_fixed_addresses
>>   };
>>   
>> @@ -71,6 +80,7 @@ enum fixed_addresses {
>>   #define FIXADDR_START		(FIXADDR_TOP - __FIXADDR_SIZE)
>>   
>>   #define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NCG
>> +#define FIXMAP_PAGE_IO	PAGE_KERNEL_NCG
>>   
>>   #include <asm-generic/fixmap.h>
>>   
>> @@ -85,5 +95,7 @@ static inline void __set_fixmap(enum fixed_addresses idx,
>>   	map_kernel_page(__fix_to_virt(idx), phys, flags);
>>   }
>>   
>> +#define __early_set_fixmap	__set_fixmap
>> +
>>   #endif /* !__ASSEMBLY__ */
>>   #endif
>> diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
>> index a7541edf0cdb..dcffe927f5b9 100644
>> --- a/arch/powerpc/kernel/setup_32.c
>> +++ b/arch/powerpc/kernel/setup_32.c
>> @@ -44,6 +44,7 @@
>>   #include <asm/asm-prototypes.h>
>>   #include <asm/kdump.h>
>>   #include <asm/feature-fixups.h>
>> +#include <asm/early_ioremap.h>
>>   
>>   #include "setup.h"
>>   
>> @@ -80,6 +81,8 @@ notrace void __init machine_init(u64 dt_ptr)
>>   	/* Configure static keys first, now that we're relocated. */
>>   	setup_feature_keys();
>>   
>> +	early_ioremap_setup();
>> +
>>   	/* Enable early debugging if any specified (see udbg.h) */
>>   	udbg_early_init();
>>   
>> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
>> index 44b4c432a273..b85f6a1cc3a1 100644
>> --- a/arch/powerpc/kernel/setup_64.c
>> +++ b/arch/powerpc/kernel/setup_64.c
>> @@ -65,6 +65,7 @@
>>   #include <asm/hw_irq.h>
>>   #include <asm/feature-fixups.h>
>>   #include <asm/kup.h>
>> +#include <asm/early_ioremap.h>
>>   
>>   #include "setup.h"
>>   
>> @@ -338,6 +339,8 @@ void __init early_setup(unsigned long dt_ptr)
>>   	apply_feature_fixups();
>>   	setup_feature_keys();
>>   
>> +	early_ioremap_setup();
>> +
>>   	/* Initialize the hash table or TLB handling */
>>   	early_init_mmu();
>>   
> 
> Can we remove early_ioremap_range() after this?
> 

Yes, once all early callers of ioremap functions are converted to using 
early_ioremap()

Christophe