[v14,6/9] acpi/arm64: Add memory-mapped timer support in GTDT driver

Message ID 1475086637-1914-7-git-send-email-fu.wei@linaro.org
State New
Headers show

Commit Message

Fu Wei Sept. 28, 2016, 6:17 p.m.
From: Fu Wei <fu.wei@linaro.org>


On platforms booting with ACPI, architected memory-mapped timers'
configuration data is provided by firmware through the ACPI GTDT
static table.

The clocksource architected timer kernel driver requires a firmware
interface to collect timer configuration and configure its driver.
this infrastructure is present for device tree systems, but it is
missing on systems booting with ACPI.

Implement the kernel infrastructure required to parse the static
ACPI GTDT table so that the architected timer clocksource driver can
make use of it on systems booting with ACPI, therefore enabling
the corresponding timers configuration.

Signed-off-by: Fu Wei <fu.wei@linaro.org>

Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>

---
 drivers/acpi/arm64/gtdt.c            | 70 ++++++++++++++++++++++++++++++++++++
 include/clocksource/arm_arch_timer.h | 15 ++++++++
 include/linux/acpi.h                 |  1 +
 3 files changed, 86 insertions(+)

-- 
2.7.4

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Comments

Mark Rutland Oct. 21, 2016, 11:19 a.m. | #1
On Thu, Sep 29, 2016 at 02:17:14AM +0800, fu.wei@linaro.org wrote:
> From: Fu Wei <fu.wei@linaro.org>

> 

> On platforms booting with ACPI, architected memory-mapped timers'

> configuration data is provided by firmware through the ACPI GTDT

> static table.

> 

> The clocksource architected timer kernel driver requires a firmware

> interface to collect timer configuration and configure its driver.

> this infrastructure is present for device tree systems, but it is

> missing on systems booting with ACPI.

> 

> Implement the kernel infrastructure required to parse the static

> ACPI GTDT table so that the architected timer clocksource driver can

> make use of it on systems booting with ACPI, therefore enabling

> the corresponding timers configuration.

> 

> Signed-off-by: Fu Wei <fu.wei@linaro.org>

> Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>

> ---

>  drivers/acpi/arm64/gtdt.c            | 70 ++++++++++++++++++++++++++++++++++++

>  include/clocksource/arm_arch_timer.h | 15 ++++++++

>  include/linux/acpi.h                 |  1 +

>  3 files changed, 86 insertions(+)

> 

> diff --git a/drivers/acpi/arm64/gtdt.c b/drivers/acpi/arm64/gtdt.c

> index b24844d..b6021db 100644

> --- a/drivers/acpi/arm64/gtdt.c

> +++ b/drivers/acpi/arm64/gtdt.c

> @@ -150,3 +150,73 @@ int __init acpi_gtdt_init(struct acpi_table_header *table)

>  

>  	return gtdt->platform_timer_count;

>  }

> +

> +static int __init gtdt_parse_gt_block(struct acpi_gtdt_timer_block *block,

> +				      struct gt_block_data *data)

> +{

> +	struct acpi_gtdt_timer_entry *frame;

> +	int i;

> +

> +	if (!block || !data)

> +		return -EINVAL;


As far as I can see, the !block case cannot happen; if it can, we'd
already have derferenced it with the is_timer_block() check in
gtdt_arch_timer_mem_init().

Why do we not handle the !data check in gtdt_arch_timer_mem_init()? It
seems fragile, given we add an index there...

> +

> +	if (!block->block_address || !block->timer_count)

> +		return -EINVAL;


Looking at Table 5-120 in the ACPI 6.1 spec, zero is not called out as
an invalid physical address for the block...

Surely if you don't have an MMIO timer, you don't have a GT Block
Structure, rather than an invalid one!?

The block->timer_count check should be more thorough, e.g.

	if (!block->timer_count) {
		pr_warn("GTDT present, but frame count is zero");
		return -ENODEV:
	}

	if (block->timer_count > 8) {
		pr_warn(FW_BUG "GTDT lists %d frames, ACPI spec only allows 8\n",
			block->timer_count);
	}

... note that without the latter we could go off the end of the array...


> +	data->cntctlbase_phy = (phys_addr_t)block->block_address;

> +	data->timer_count = block->timer_count;

> +

> +	frame = (void *)block + block->timer_offset;

> +	if (frame + block->timer_count != (void *)block + block->header.length)

> +		return -EINVAL;

> +

> +	/*

> +	 * Get the GT timer Frame data for every GT Block Timer

> +	 */

> +	for (i = 0; i < block->timer_count; i++, frame++) {

> +		if (!frame->base_address || !frame->timer_interrupt)

> +			return -EINVAL;

> +

> +		data->timer[i].irq = map_gt_gsi(frame->timer_interrupt,

> +						frame->timer_flags);

> +		if (data->timer[i].irq <= 0)

> +			return -EINVAL;


Can we please print something describing the failure, e.g.

	pr_warn("failed to map GTDT frame %d, physical timer interrupt\n",
		i);

> +

> +		if (frame->virtual_timer_interrupt) {


Same comment as previously about GSIV zero being valid; this is arguably
a spec bug that should be reported...

> +			data->timer[i].virtual_irq =

> +				map_gt_gsi(frame->virtual_timer_interrupt,

> +					   frame->virtual_timer_flags);

> +			if (data->timer[i].virtual_irq <= 0)

> +				return -EINVAL;


Likewise, a message here would be useful, e.g.

	pr_warn("failed to map GTDT frame %d, virtual timer interrupt\n",
		i);

> +		}

> +

> +		data->timer[i].frame_nr = frame->frame_number;

> +		data->timer[i].cntbase_phy = frame->base_address;


What about CntEL0BaseX?

> +	}

> +

> +	return 0;

> +}

> +

> +/*

> + * Get the GT block info for memory-mapped timer from GTDT table.

> + */

> +int __init gtdt_arch_timer_mem_init(struct gt_block_data *data)

> +{

> +	void *platform_timer;

> +	int index = 0;

> +	int ret;

> +

> +	for_each_platform_timer(platform_timer) {

> +		if (!is_timer_block(platform_timer))

> +			continue;

> +		ret = gtdt_parse_gt_block(platform_timer, data + index);

> +		if (ret)

> +			return ret;

> +		index++;

> +	}

> +

> +	if (index)

> +		pr_info("found %d memory-mapped timer block(s).\n", index);

> +

> +	return index;

> +}

> diff --git a/include/clocksource/arm_arch_timer.h b/include/clocksource/arm_arch_timer.h

> index 16dcd10..94a5d14 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


Nit: please call this ARCH_TIMER_MEM_MAX_FRAMES, so it's clear that the
maximum index is 7.

>  #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 {


s/gt_timer_data/arch_timer_mem_frame/

> +	int frame_nr;

> +	phys_addr_t cntbase_phy;


Please get rid of the '_phy' suffix; it clashes with other terminology,
'phys' is generally preferable, and given the name and type it's obvious
that it's a physical address anyhow.

Just call this 'cntbase'.

> +	int irq;

> +	int virtual_irq;


Call these phys_irq and virt_irq.

> +};

> +

> +struct gt_block_data {


s/gt_block_data/arch_timer_mem/

> +	phys_addr_t cntctlbase_phy;


Same comment w.r.t. the '_phy' suffix. Likewise, just call this
'cntctlbase_phy'

> +	int timer_count;


s/timer_count/num_frames/

> +	struct gt_timer_data timer[ARCH_TIMER_MEM_MAX_FRAME];

> +};


Please split this part out into a patch which moves the existing driver
over to this new abstraction, *then* introduce the ACPI parser for it in
a subsequent patch.

Thanks,
Mark.
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Patch hide | download patch | download mbox

diff --git a/drivers/acpi/arm64/gtdt.c b/drivers/acpi/arm64/gtdt.c
index b24844d..b6021db 100644
--- a/drivers/acpi/arm64/gtdt.c
+++ b/drivers/acpi/arm64/gtdt.c
@@ -150,3 +150,73 @@  int __init acpi_gtdt_init(struct acpi_table_header *table)
 
 	return gtdt->platform_timer_count;
 }
+
+static int __init gtdt_parse_gt_block(struct acpi_gtdt_timer_block *block,
+				      struct gt_block_data *data)
+{
+	struct acpi_gtdt_timer_entry *frame;
+	int i;
+
+	if (!block || !data)
+		return -EINVAL;
+
+	if (!block->block_address || !block->timer_count)
+		return -EINVAL;
+
+	data->cntctlbase_phy = (phys_addr_t)block->block_address;
+	data->timer_count = block->timer_count;
+
+	frame = (void *)block + block->timer_offset;
+	if (frame + block->timer_count != (void *)block + block->header.length)
+		return -EINVAL;
+
+	/*
+	 * Get the GT timer Frame data for every GT Block Timer
+	 */
+	for (i = 0; i < block->timer_count; i++, frame++) {
+		if (!frame->base_address || !frame->timer_interrupt)
+			return -EINVAL;
+
+		data->timer[i].irq = map_gt_gsi(frame->timer_interrupt,
+						frame->timer_flags);
+		if (data->timer[i].irq <= 0)
+			return -EINVAL;
+
+		if (frame->virtual_timer_interrupt) {
+			data->timer[i].virtual_irq =
+				map_gt_gsi(frame->virtual_timer_interrupt,
+					   frame->virtual_timer_flags);
+			if (data->timer[i].virtual_irq <= 0)
+				return -EINVAL;
+		}
+
+		data->timer[i].frame_nr = frame->frame_number;
+		data->timer[i].cntbase_phy = frame->base_address;
+	}
+
+	return 0;
+}
+
+/*
+ * Get the GT block info for memory-mapped timer from GTDT table.
+ */
+int __init gtdt_arch_timer_mem_init(struct gt_block_data *data)
+{
+	void *platform_timer;
+	int index = 0;
+	int ret;
+
+	for_each_platform_timer(platform_timer) {
+		if (!is_timer_block(platform_timer))
+			continue;
+		ret = gtdt_parse_gt_block(platform_timer, data + index);
+		if (ret)
+			return ret;
+		index++;
+	}
+
+	if (index)
+		pr_info("found %d memory-mapped timer block(s).\n", index);
+
+	return index;
+}
diff --git a/include/clocksource/arm_arch_timer.h b/include/clocksource/arm_arch_timer.h
index 16dcd10..94a5d14 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 virtual_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 e2f9841..5dc0b85 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -571,6 +571,7 @@  int acpi_reconfig_notifier_unregister(struct notifier_block *nb);
 int acpi_gtdt_init(struct acpi_table_header *table);
 int acpi_gtdt_map_ppi(int type);
 bool acpi_gtdt_c3stop(void);
+int gtdt_arch_timer_mem_init(struct gt_block_data *data);
 #endif
 
 #else	/* !CONFIG_ACPI */