From mboxrd@z Thu Jan 1 00:00:00 1970 From: fu.wei@linaro.org (Fu Wei) Date: Wed, 20 Jul 2016 02:28:04 +0800 Subject: [PATCH v7 7/9] acpi/arm64: Add memory-mapped timer support in GTDT driver In-Reply-To: <20160714134251.GA30657@red-moon> References: <1468432402-4872-1-git-send-email-fu.wei@linaro.org> <1468432402-4872-8-git-send-email-fu.wei@linaro.org> <20160714134251.GA30657@red-moon> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Lorenzo, I have updated my patchset following all your comments. I have just posted v8 patchset, please check. Great thanks for your comments, they are very helpful :-) On 14 July 2016 at 21:42, Lorenzo Pieralisi wrote: > On Thu, Jul 14, 2016 at 01:53:20AM +0800, fu.wei at linaro.org wrote: >> From: Fu Wei >> >> This driver adds support for parsing memory-mapped timer in GTDT: >> provide a kernel APIs to parse GT Block Structure in GTDT, >> export all the info by filling the struct which provided >> by parameter(pointer of the struct). >> >> By this driver, we can add ACPI support for memory-mapped timer in >> arm_arch_timer drivers, and separate the ACPI GTDT knowledge from it. >> >> Signed-off-by: Fu Wei >> Signed-off-by: Hanjun Guo >> --- >> drivers/acpi/arm64/acpi_gtdt.c | 90 ++++++++++++++++++++++++++++++++++++ >> include/clocksource/arm_arch_timer.h | 15 ++++++ >> include/linux/acpi.h | 1 + >> 3 files changed, 106 insertions(+) >> >> diff --git a/drivers/acpi/arm64/acpi_gtdt.c b/drivers/acpi/arm64/acpi_gtdt.c >> index 9ee977d..ff62953 100644 >> --- a/drivers/acpi/arm64/acpi_gtdt.c >> +++ b/drivers/acpi/arm64/acpi_gtdt.c >> @@ -168,3 +168,93 @@ int __init gtdt_arch_timer_init(struct acpi_table_header *table) >> >> return -EINVAL; >> } >> + >> +/* >> + * Helper function for getting the pointer of a timer frame in GT block. >> + */ >> +static void __init *gtdt_gt_timer_frame(struct acpi_gtdt_timer_block *gt_block, >> + int index) >> +{ >> + void *timer_frame = (void *)gt_block + gt_block->timer_offset + >> + sizeof(struct acpi_gtdt_timer_entry) * index; >> + >> + if (timer_frame <= (void *)gt_block + gt_block->header.length - >> + sizeof(struct acpi_gtdt_timer_entry)) >> + return timer_frame; > > Nit: gt_block is an array, right ? I think it would be much simpler > if you treat is as such, so that indexing into it would be done > automatically by the compiler. Actually, I do not even think you > would need this function at all if you treat gt_block as an array, > the length check could be done in gtdt_parse_gt_block() straight > away. > >> + >> + return NULL; >> +} >> + >> +static int __init gtdt_parse_gt_block(void *platform_timer, int index, >> + void *data) >> +{ >> + struct acpi_gtdt_timer_block *block; >> + struct acpi_gtdt_timer_entry *frame; >> + struct gt_block_data *block_data; >> + int i, j; >> + >> + if (!platform_timer || !data) >> + return -EINVAL; >> + >> + block = platform_timer; >> + block_data = data + sizeof(struct gt_block_data) * index; > > Nit: See above, data is a struct gt_block_data[] right ? These void > pointers parameters are not really great, the caller context > knows what they are and it can pass them as pointer to typed > array elements anyway unless I am missing something. > >> + if (!block->block_address || !block->timer_count) { >> + pr_err(FW_BUG "invalid GT Block data.\n"); >> + return -EINVAL; >> + } >> + block_data->cntctlbase_phy = (phys_addr_t)block->block_address; >> + block_data->timer_count = block->timer_count; >> + >> + /* >> + * Get the GT timer Frame data for every GT Block Timer >> + */ >> + for (i = 0, j = 0; i < block->timer_count; i++) { > > What's j needed for (ie can't you use just i instead ?) ? > >> + frame = gtdt_gt_timer_frame(block, i); >> + if (!frame || !frame->base_address || !frame->timer_interrupt) { >> + pr_err(FW_BUG "invalid GT Block Timer data.\n"); >> + return -EINVAL; >> + } >> + block_data->timer[j].frame_nr = frame->frame_number; >> + block_data->timer[j].cntbase_phy = frame->base_address; >> + block_data->timer[j].irq = map_generic_timer_interrupt( >> + frame->timer_interrupt, >> + frame->timer_flags); >> + if (frame->virtual_timer_interrupt) >> + block_data->timer[j].virt_irq = >> + map_generic_timer_interrupt( >> + frame->virtual_timer_interrupt, >> + frame->virtual_timer_flags); >> + j++; >> + } >> + >> + if (j) >> + return 0; >> + >> + block_data->cntctlbase_phy = (phys_addr_t)NULL; > > This is wrong. NULL is not meant to be used as a physical address, > you must not do that. Is not zeroeing timer_count enough ? I have > to understand why you need this because casting NULL into it is > not safe, at all. > >> + block_data->timer_count = 0; >> + >> + return -EINVAL; >> +} >> + >> +/* >> + * Get the GT block info for memory-mapped timer from GTDT table. >> + * Please make sure we have called gtdt_arch_timer_init, because it helps to >> + * init the global variables. > > It is a helper function that you call once at boot, you easily > determine when it is called, it is not meant to be used in different > contexts from different subsystems; I think that this comment > is not clear so either you make it clearer or you remove it. > >> + */ >> +int __init gtdt_arch_timer_mem_init(struct gt_block_data *data) >> +{ >> + void *platform_timer; >> + int index = 0; >> + >> + for_each_platform_timer(platform_timer) { >> + if (is_timer_block(platform_timer) && >> + !gtdt_parse_gt_block(platform_timer, index, data)) > > Passing around these opaque void* is a tad ugly, see my comments > above about this. > > Apart from the NULL pointer assignment, everything else is just code > clean-up. > > Thanks, > Lorenzo > >> + index++; >> + } >> + >> + if (index) >> + pr_info("found %d memory-mapped timer block.\n", index); >> + >> + return index; >> +} >> diff --git a/include/clocksource/arm_arch_timer.h b/include/clocksource/arm_arch_timer.h >> index 16dcd10..ece6b3b 100644 >> --- a/include/clocksource/arm_arch_timer.h >> +++ b/include/clocksource/arm_arch_timer.h >> @@ -56,6 +56,8 @@ enum spi_nr { >> #define ARCH_TIMER_MEM_PHYS_ACCESS 2 >> #define ARCH_TIMER_MEM_VIRT_ACCESS 3 >> >> +#define ARCH_TIMER_MEM_MAX_FRAME 8 >> + >> #define ARCH_TIMER_USR_PCT_ACCESS_EN (1 << 0) /* physical counter */ >> #define ARCH_TIMER_USR_VCT_ACCESS_EN (1 << 1) /* virtual counter */ >> #define ARCH_TIMER_VIRT_EVT_EN (1 << 2) >> @@ -71,6 +73,19 @@ struct arch_timer_kvm_info { >> int virtual_irq; >> }; >> >> +struct gt_timer_data { >> + int frame_nr; >> + phys_addr_t cntbase_phy; >> + int irq; >> + int virt_irq; >> +}; >> + >> +struct gt_block_data { >> + phys_addr_t cntctlbase_phy; >> + int timer_count; >> + struct gt_timer_data timer[ARCH_TIMER_MEM_MAX_FRAME]; >> +}; >> + >> #ifdef CONFIG_ARM_ARCH_TIMER >> >> extern u32 arch_timer_get_rate(void); >> diff --git a/include/linux/acpi.h b/include/linux/acpi.h >> index 8439579..b1cacbc 100644 >> --- a/include/linux/acpi.h >> +++ b/include/linux/acpi.h >> @@ -536,6 +536,7 @@ struct platform_device *acpi_create_platform_device(struct acpi_device *); >> int __init gtdt_arch_timer_init(struct acpi_table_header *table); >> int __init acpi_gtdt_map_ppi(int type); >> int __init acpi_gtdt_c3stop(void); >> +int __init gtdt_arch_timer_mem_init(struct gt_block_data *data); >> #endif >> >> #else /* !CONFIG_ACPI */ >> -- >> 2.5.5 >> -- Best regards, Fu Wei Software Engineer Red Hat