Re: [PATCH v4 3/9] spi: Support selection of the index of the ACPI Spi Resource before alloc

Hi Stefan,

On 1/20/22 14:43, Stefan Binding wrote:

If a node contains more than one Spi Resources, it may be necessary to use an index to select which one you want to allocate a spi device for.

Signed-off-by: Stefan Binding sbinding@opensource.cirrus.com

drivers/spi/spi.c | 56 +++++++++++++++++++++++++++++++++++------ include/linux/spi/spi.h | 6 +++-- 2 files changed, 52 insertions(+), 10 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 13f4701f0694..898cc9931490 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -2320,6 +2320,9 @@ struct acpi_spi_lookup { int irq; u8 bits_per_word; u8 chip_select;

• int n;
• int index;
• int irq_index;

};

static void acpi_spi_parse_apple_properties(struct acpi_device *dev, @@ -2351,6 +2354,8 @@ static void acpi_spi_parse_apple_properties(struct acpi_device *dev, lookup->mode |= SPI_CPHA; }

+static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev);

static int acpi_spi_add_resource(struct acpi_resource *ares, void *data) { struct acpi_spi_lookup *lookup = data; @@ -2364,14 +2369,35 @@ static int acpi_spi_add_resource(struct acpi_resource *ares, void *data) sb = &ares->data.spi_serial_bus; if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {

• 	if (lookup->index != -1 && lookup->n++ != lookup->index)
  

• 		return 1;
  

• 	if (lookup->index == -1 && !ctlr)
  

• 		return -ENODEV;
  

• status = acpi_get_handle(NULL,
  			 sb->resource_source.string_ptr,
  			 &parent_handle);
  
  

• 	if (ACPI_FAILURE(status) ||
  

• 	    ACPI_HANDLE(ctlr->dev.parent) != parent_handle)
  

• 	if (ACPI_FAILURE(status))
  	return -ENODEV;
  
  

• 	if (ctlr) {
  

• 		if (ACPI_HANDLE(ctlr->dev.parent) != parent_handle)
  

• 			return -ENODEV;
  

• 	} else {
  

• 		struct acpi_device *adev;
  

• 		if (acpi_bus_get_device(parent_handle, &adev))
  

• 			return -ENODEV;
  

• 		ctlr = acpi_spi_find_controller_by_adev(adev);
  

• 		if (!ctlr)
  

• 			return -ENODEV;
  

• 		lookup->ctlr = ctlr;
  

• 	}
  

• /*
   * ACPI DeviceSelection numbering is handled by the
   * host controller driver in Windows and can vary
  

All of the above looks good to me.

@@ -2402,7 +2428,7 @@ static int acpi_spi_add_resource(struct acpi_resource *ares, void *data) } else if (lookup->irq < 0) { struct resource r;

• if (acpi_dev_resource_interrupt(ares, 0, &r))
  

• if (acpi_dev_resource_interrupt(ares, lookup->irq_index, &r))
  lookup->irq = r.start;
  

  }

I think that this does not do what you want it to do. Quoting drivers/acpi/resource.c:

bool acpi_dev_resource_interrupt(struct acpi_resource *ares, int index, struct resource *res) { struct acpi_resource_irq *irq; struct acpi_resource_extended_irq *ext_irq;

switch (ares->type) { case ACPI_RESOURCE_TYPE_IRQ: /* * Per spec, only one interrupt per descriptor is allowed in * _CRS, but some firmware violates this, so parse them all. */ irq = &ares->data.irq; if (index >= irq->interrupt_count) { irqresource_disabled(res, 0); return false; }

So now you are actually adding an index into a single:

Interrupt (ResourceConsumer, Level, ActiveHigh, Exclusive, ,, ) { 0x00000008, }

ACPI Resource, which typically (as shown here) only has 1 interrupt, I guess what you want is the nth resource of type ACPI_RESOURCE_TYPE_IRQ or ACPI_RESOURCE_TYPE_EXTENDED_IRQ.

So to make this work you should combine this with a separate irq_n for irq_index, increment that on acpi_dev_resource_interrupt() success and then only set lookup->irq = r.start; when irq_n == irq_index.

But since the bus-multi-inst code already has its own irq getting code this is not really necessary, I would just drop the new irq_index field; and then also drop the "if (spi_dev->irq < 0)" condition for calling bmi_get_irq() in "[PATCH v4 7/9] platform/x86: bus-multi-instantiate: Add SPI support"

Note that for the CS35L41 that if is always true already since that is using a GpioInt resource and acpi_dev_resource_interrupt() does not support those.

TL;DR: please drop the new irq_index fiels and just leave the related bits as is.

@@ -2414,14 +2440,22 @@ static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)

• acpi_spi_device_alloc - Allocate a spi device, and fill it in with ACPI information
• @ctlr: controller to which the spi device belongs
• @adev: ACPI Device for the spi device

• • @index: Index of the spi resource inside the ACPI Node
• • @irq_index: Index of the GPIO resource for the IRQ inside the ACPI Node
  • This should be used to allocate a new spi device from and ACPI Node.
  • The caller is responsible for calling spi_add_device to register the spi device.
• • If ctlr is set to NULL, the Controller for the spi device will be looked up
• • using the resource.
• • If index is set to -1, index is not used.
• • Note: If index is -1, ctlr must be set.
• • Return: a pointer to the new device, or ERR_PTR on error.
  */

struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,

• 			 struct acpi_device *adev)
  

• 			 struct acpi_device *adev,
  

• 			 int index, int irq_index)
  

{ acpi_handle parent_handle = NULL; struct list_head resource_list; @@ -2429,8 +2463,14 @@ struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr, struct spi_device *spi; int ret;

• if (!ctlr && index == -1)

• return ERR_PTR(-EINVAL);
  

• lookup.ctlr = ctlr; lookup.irq = -1;

• lookup.index = index;

• lookup.n = 0;

• lookup.irq_index = irq_index;

  INIT_LIST_HEAD(&resource_list); ret = acpi_dev_get_resources(adev, &resource_list,

@@ -2443,7 +2483,7 @@ struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,

if (!lookup.max_speed_hz && ACPI_SUCCESS(acpi_get_parent(adev->handle, &parent_handle)) &&

•    ACPI_HANDLE(ctlr->dev.parent) == parent_handle) {
  

•    ACPI_HANDLE(lookup.ctlr->dev.parent) == parent_handle) {
  

  /* Apple does not use _CRS but nested devices for SPI slaves */ acpi_spi_parse_apple_properties(adev, &lookup); }

@@ -2451,9 +2491,9 @@ struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr, if (!lookup.max_speed_hz) return ERR_PTR(-ENODEV);

• spi = spi_alloc_device(ctlr);

• spi = spi_alloc_device(lookup.ctlr); if (!spi) {

• dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
  

• dev_err(&lookup.ctlr->dev, "failed to allocate SPI device for %s\n",
  dev_name(&adev->dev));
  

  return ERR_PTR(-ENOMEM); }

@@ -2478,7 +2518,7 @@ static acpi_status acpi_register_spi_device(struct spi_controller *ctlr, acpi_device_enumerated(adev)) return AE_OK;

• spi = acpi_spi_device_alloc(ctlr, adev);

• spi = acpi_spi_device_alloc(ctlr, adev, -1, 0); if (IS_ERR(spi)) { if (PTR_ERR(spi) == -ENOMEM) return AE_NO_MEMORY;

diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 200725692b93..1a34fd0f6ca2 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -762,10 +762,12 @@ extern void spi_unregister_controller(struct spi_controller *ctlr);

#if IS_ENABLED(CONFIG_ACPI) extern struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,

• 				struct acpi_device *adev);
  

• 				struct acpi_device *adev,
  

• 				int index, int irq_index);
  

#else static inline struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,

• 				       struct acpi_device *adev);
  

• 				       struct acpi_device *adev,
  

• 				       int index, int irq_index);
  

{ return ERR_PTR(-EOPNOTSUPP); }

Like with my review of patch 2/9, I don't think we need stubs here.

Regards,

Hans