Re: [PATCH v13 4/9] PCI: Apply the new generic I/O management on PCI IO hosts

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On 13/02/2018 22:57, dann frazier wrote:
On Wed, Feb 14, 2018 at 01:45:28AM +0800, John Garry wrote:
From: Zhichang Yuan <yuanzhichang@xxxxxxxxxxxxx>

After introducing the new generic I/O space management in logic pio, the
original PCI MMIO relevant helpers need to be updated based on the new
interfaces.
This patch adapts the corresponding code to match the changes introduced
by logic pio.

Signed-off-by: Zhichang Yuan <yuanzhichang@xxxxxxxxxxxxx>
Signed-off-by: Gabriele Paoloni <gabriele.paoloni@xxxxxxxxxx>
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>        #earlier draft
Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>

I saw that Bjorn Acked this back in v6, but it seems like the code in
pci.c was reworked a bit for v7 onwards and I didn't see a follow-up
review (apologies if I just missed it). In which case, maybe his Ack
should have the "#earlier draft" tag as well?


Hi Dann,

I see Bjorn acked again later on in the series, here:
https://lkml.org/lkml/2017/5/26/612

---
 drivers/pci/pci.c        | 95 +++++++++---------------------------------------
 include/asm-generic/io.h |  2 +-
 2 files changed, 18 insertions(+), 79 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 07290a3..8aa5c54 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -22,6 +22,7 @@
 #include <linux/spinlock.h>
 #include <linux/string.h>
 #include <linux/log2.h>
+#include <linux/logic_pio.h>
 #include <linux/pci-aspm.h>
 #include <linux/pm_wakeup.h>
 #include <linux/interrupt.h>
@@ -3440,17 +3441,6 @@ int pci_request_regions_exclusive(struct pci_dev *pdev, const char *res_name)
 }
 EXPORT_SYMBOL(pci_request_regions_exclusive);

-#ifdef PCI_IOBASE
-struct io_range {
-	struct list_head list;
-	phys_addr_t start;
-	resource_size_t size;
-};
-
-static LIST_HEAD(io_range_list);
-static DEFINE_SPINLOCK(io_range_lock);
-#endif
-
 /*
  * Record the PCI IO range (expressed as CPU physical address + size).
  * Return a negative value if an error has occured, zero otherwise
@@ -3458,51 +3448,28 @@ struct io_range {
 int pci_register_io_range(struct fwnode_handle *fwnode, phys_addr_t addr,
 			resource_size_t	size)
 {
-	int err = 0;
-
+	int ret = 0;
 #ifdef PCI_IOBASE
-	struct io_range *range;
-	resource_size_t allocated_size = 0;
-
-	/* check if the range hasn't been previously recorded */
-	spin_lock(&io_range_lock);
-	list_for_each_entry(range, &io_range_list, list) {
-		if (addr >= range->start && addr + size <= range->start + size) {
-			/* range already registered, bail out */
-			goto end_register;
-		}
-		allocated_size += range->size;
-	}
+	struct logic_pio_hwaddr *range;

-	/* range not registed yet, check for available space */
-	if (allocated_size + size - 1 > IO_SPACE_LIMIT) {
-		/* if it's too big check if 64K space can be reserved */
-		if (allocated_size + SZ_64K - 1 > IO_SPACE_LIMIT) {
-			err = -E2BIG;
-			goto end_register;
-		}
-
-		size = SZ_64K;
-		pr_warn("Requested IO range too big, new size set to 64K\n");
-	}
+	if (!size || addr + size < addr)
+		return -EINVAL;

-	/* add the range to the list */
 	range = kzalloc(sizeof(*range), GFP_ATOMIC);
-	if (!range) {
-		err = -ENOMEM;
-		goto end_register;
-	}
+	if (!range)
+		return -ENOMEM;

-	range->start = addr;
+	range->fwnode = fwnode;
 	range->size = size;
+	range->hw_start = addr;
+	range->flags = PIO_CPU_MMIO;

-	list_add_tail(&range->list, &io_range_list);
-
-end_register:
-	spin_unlock(&io_range_lock);
+	ret = logic_pio_register_range(range);
+	if (ret)
+		kfree(range);
 #endif

-	return err;
+	return ret;
 }

 phys_addr_t pci_pio_to_address(unsigned long pio)
@@ -3510,21 +3477,10 @@ phys_addr_t pci_pio_to_address(unsigned long pio)
 	phys_addr_t address = (phys_addr_t)OF_BAD_ADDR;

 #ifdef PCI_IOBASE
-	struct io_range *range;
-	resource_size_t allocated_size = 0;
-
-	if (pio > IO_SPACE_LIMIT)
+	if (pio >= MMIO_UPPER_LIMIT)
 		return address;

-	spin_lock(&io_range_lock);
-	list_for_each_entry(range, &io_range_list, list) {
-		if (pio >= allocated_size && pio < allocated_size + range->size) {
-			address = range->start + pio - allocated_size;
-			break;
-		}
-		allocated_size += range->size;
-	}
-	spin_unlock(&io_range_lock);
+	address = logic_pio_to_hwaddr(pio);
 #endif

 	return address;
@@ -3533,25 +3489,8 @@ phys_addr_t pci_pio_to_address(unsigned long pio)
 unsigned long __weak pci_address_to_pio(phys_addr_t address)
 {
 #ifdef PCI_IOBASE
-	struct io_range *res;
-	resource_size_t offset = 0;
-	unsigned long addr = -1;
-
-	spin_lock(&io_range_lock);
-	list_for_each_entry(res, &io_range_list, list) {
-		if (address >= res->start && address < res->start + res->size) {
-			addr = address - res->start + offset;
-			break;
-		}
-		offset += res->size;
-	}
-	spin_unlock(&io_range_lock);
-
-	return addr;
+	return logic_pio_trans_cpuaddr(address);
 #else
-	if (address > IO_SPACE_LIMIT)
-		return (unsigned long)-1;
-

Why is this check now safe to drop in the !PCI_IOBASE case?

So I have been studying the (long) patchset history and I don't see the reason for removing this check, and I think it can be reinstated.

The address and pio are analogous here, and pio should not exceed the IO space limit, so just a safety check.


  -dann

 	return (unsigned long) address;
 #endif
 }
diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index b7996a79..5a59931 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -901,7 +901,7 @@ static inline void iounmap(void __iomem *addr)
 #define ioport_map ioport_map
 static inline void __iomem *ioport_map(unsigned long port, unsigned int nr)
 {

Thanks,
John

-	return PCI_IOBASE + (port & IO_SPACE_LIMIT);
+	return PCI_IOBASE + (port & MMIO_UPPER_LIMIT);
 }
 #endif


.



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