On Mon, 2020-02-03 at 12:49 +0000, Jonathan Cameron wrote:

On Tue, 3 Dec 2019 14:46:35 +1100
Alastair D'Silva [off-list ref] wrote:

quoted

From: Alastair D'Silva <redacted>

Add functions to map/unmap LPC memory

Signed-off-by: Alastair D'Silva <redacted>
---
 drivers/misc/ocxl/config.c        |  4 +++
 drivers/misc/ocxl/core.c          | 50
+++++++++++++++++++++++++++++++
 drivers/misc/ocxl/ocxl_internal.h |  3 ++
 include/misc/ocxl.h               | 18 +++++++++++
 4 files changed, 75 insertions(+)

diff --git a/drivers/misc/ocxl/config.c

b/drivers/misc/ocxl/config.c
index c8e19bfb5ef9..fb0c3b6f8312 100644

--- a/drivers/misc/ocxl/config.c
+++ b/drivers/misc/ocxl/config.c

@@ -568,6 +568,10 @@ static int read_afu_lpc_memory_info(struct

pci_dev *dev,
 		afu->special_purpose_mem_size =
 			total_mem_size - lpc_mem_size;
 	}
+
+	dev_info(&dev->dev, "Probed LPC memory of %#llx bytes and
special purpose memory of %#llx bytes\n",
+		afu->lpc_mem_size, afu->special_purpose_mem_size);
+

If we are being fussy, this block has nothing todo with the rest of
the patch
so we should be seeing it here.

Agreed

quoted

 	return 0;
 }
 

diff --git a/drivers/misc/ocxl/core.c b/drivers/misc/ocxl/core.c
index 2531c6cf19a0..98611faea219 100644
--- a/drivers/misc/ocxl/core.c
+++ b/drivers/misc/ocxl/core.c

@@ -210,6 +210,55 @@ static void unmap_mmio_areas(struct ocxl_afu

*afu)
 	release_fn_bar(afu->fn, afu->config.global_mmio_bar);
 }
 
+int ocxl_afu_map_lpc_mem(struct ocxl_afu *afu)
+{
+	struct pci_dev *dev = to_pci_dev(afu->fn->dev.parent);
+
+	if ((afu->config.lpc_mem_size + afu-

quoted

config.special_purpose_mem_size) == 0)

+		return 0;
+
+	afu->lpc_base_addr = ocxl_link_lpc_map(afu->fn->link, dev);
+	if (afu->lpc_base_addr == 0)
+		return -EINVAL;
+
+	if (afu->config.lpc_mem_size) {

I was happy with the explicit check on 0 above, but we should be
consistent.  Either
we make use of 0 == false, or we don't and explicitly check vs 0.

Hence

if (afu->config.pc_mem_size != 0) { 

here or

if (!(afu->config.pc_mem_size + afu-

quoted

config.special_purpose_mem_size))

	return 0;

above.

This feels a bit niggly, but sure, changed to a '> 0' check.

quoted

+		afu->lpc_res.start = afu->lpc_base_addr + afu-

quoted

config.lpc_mem_offset;

+		afu->lpc_res.end = afu->lpc_res.start + afu-

quoted

config.lpc_mem_size - 1;

+	}
+
+	if (afu->config.special_purpose_mem_size) {
+		afu->special_purpose_res.start = afu->lpc_base_addr +
+						 afu-

quoted

config.special_purpose_mem_offset;

+		afu->special_purpose_res.end = afu-

quoted

special_purpose_res.start +

+					       afu-

quoted

config.special_purpose_mem_size - 1;

+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ocxl_afu_map_lpc_mem);
+
+struct resource *ocxl_afu_lpc_mem(struct ocxl_afu *afu)
+{
+	return &afu->lpc_res;
+}
+EXPORT_SYMBOL_GPL(ocxl_afu_lpc_mem);
+
+static void unmap_lpc_mem(struct ocxl_afu *afu)
+{
+	struct pci_dev *dev = to_pci_dev(afu->fn->dev.parent);
+
+	if (afu->lpc_res.start || afu->special_purpose_res.start) {
+		void *link = afu->fn->link;
+
+		ocxl_link_lpc_release(link, dev);
+
+		afu->lpc_res.start = 0;
+		afu->lpc_res.end = 0;
+		afu->special_purpose_res.start = 0;
+		afu->special_purpose_res.end = 0;
+	}
+}
+
 static int configure_afu(struct ocxl_afu *afu, u8 afu_idx, struct
pci_dev *dev)
 {
 	int rc;

@@ -251,6 +300,7 @@ static int configure_afu(struct ocxl_afu *afu,

u8 afu_idx, struct pci_dev *dev)
 
 static void deconfigure_afu(struct ocxl_afu *afu)
 {
+	unmap_lpc_mem(afu);

Hmm. This breaks the existing balance between configure_afu and
deconfigure_afu.

Given comments below on why we don't do map_lpc_mem in the afu bring
up
(as it's a shared operation) it seems to me that we should be doing
this
outside of the afu deconfigure.  Perhaps ocxl_function_close is
appropriate?
I don't know this infrastructure well enough to be sure.

If it does need to be here, then a comment to give more info on
why would be great!

Sure, I've added a comment in unmap_lpc_mem explaining that lpc_release
only releases the memory on the link when the last consumer calls
release.

It's in deconfigure_afu as the LPC memory is registered and reported
per-AFU (even though it has to be allocated all at once across the
link).

quoted

 	unmap_mmio_areas(afu);
 	reclaim_afu_pasid(afu);
 	reclaim_afu_actag(afu);

diff --git a/drivers/misc/ocxl/ocxl_internal.h

b/drivers/misc/ocxl/ocxl_internal.h
index 20b417e00949..9f4b47900e62 100644

--- a/drivers/misc/ocxl/ocxl_internal.h
+++ b/drivers/misc/ocxl/ocxl_internal.h

@@ -52,6 +52,9 @@ struct ocxl_afu {
 	void __iomem *global_mmio_ptr;
 	u64 pp_mmio_start;
 	void *private;
+	u64 lpc_base_addr; /* Covers both LPC & special purpose memory

*/
+	struct resource lpc_res;
+	struct resource special_purpose_res;
 };
 
 enum ocxl_context_status {

diff --git a/include/misc/ocxl.h b/include/misc/ocxl.h
index 06dd5839e438..6f7c02f0d5e3 100644
--- a/include/misc/ocxl.h
+++ b/include/misc/ocxl.h

@@ -212,6 +212,24 @@ int ocxl_irq_set_handler(struct ocxl_context

*ctx, int irq_id,
 
 // AFU Metadata
 
+/**
+ * Map the LPC system & special purpose memory for an AFU
+ *
+ * Do not call this during device discovery, as there may me
multiple
+ * devices on a link, and the memory is mapped for the whole link,
not
+ * just one device. It should only be called after all devices
have
+ * registered their memory on the link.
+ *
+ * afu: The AFU that has the LPC memory to map

Run kernel-doc over these files and fix all the errors + warnings.

Ok.

@afu: ..

and missing function name etc.

quoted

+ */
+extern int ocxl_afu_map_lpc_mem(struct ocxl_afu *afu);
+
+/**
+ * Get the physical address range of LPC memory for an AFU
+ * afu: The AFU associated with the LPC memory
+ */
+extern struct resource *ocxl_afu_lpc_mem(struct ocxl_afu *afu);
+
 /**
  * Get a pointer to the config for an AFU
  *

-- 
Alastair D'Silva
Open Source Developer
Linux Technology Centre, IBM Australia
mob: 0423 762 819