[PATCH v4 2/2] PCI: iproc: Add outbound configuration for 32-bit I/O region

From: Srinath Mannam
Date: Thu Feb 28 2019 - 23:52:49 EST


In the present driver outbound window configuration is done to map above
32-bit address I/O regions with corresponding PCI memory range given in
ranges DT property.

This patch add outbound window configuration to map below 32-bit I/O range
with corresponding PCI memory, which helps to access I/O region in ARM
32-bit and one to one mapping of I/O region to PCI memory.

Ex:
1. ranges DT property given for current driver is,
ranges = <0x83000000 0x0 0x40000000 0x4 0x00000000 0 0x40000000>;
I/O region address is 0x400000000
2. ranges DT property can be given after this patch,
ranges = <0x83000000 0x0 0x42000000 0x0 0x42000000 0 0x2000000>;
I/O region address is 0x42000000

Signed-off-by: Srinath Mannam <srinath.mannam@xxxxxxxxxxxx>
Signed-off-by: Abhishek Shah <abhishek.shah@xxxxxxxxxxxx>
Signed-off-by: Ray Jui <ray.jui@xxxxxxxxxxxx>
---
drivers/pci/controller/pcie-iproc.c | 21 +++++++++++++++++++--
1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/pcie-iproc.c b/drivers/pci/controller/pcie-iproc.c
index b882255..080f142 100644
--- a/drivers/pci/controller/pcie-iproc.c
+++ b/drivers/pci/controller/pcie-iproc.c
@@ -955,8 +955,25 @@ static int iproc_pcie_setup_ob(struct iproc_pcie *pcie, u64 axi_addr,
resource_size_t window_size =
ob_map->window_sizes[size_idx] * SZ_1M;

- if (size < window_size)
- continue;
+ /*
+ * Keep iterating until we reach the last window and
+ * with the minimal window size at index zero. In this
+ * case, we take a compromise by mapping it using the
+ * minimum window size that can be supported
+ */
+ if (size < window_size) {
+ if (size_idx > 0 || window_idx > 0)
+ continue;
+
+ /*
+ * For the corner case of reaching the minimal
+ * window size that can be supported on the
+ * last window
+ */
+ axi_addr = ALIGN_DOWN(axi_addr, window_size);
+ pci_addr = ALIGN_DOWN(pci_addr, window_size);
+ size = window_size;
+ }

if (!IS_ALIGNED(axi_addr, window_size) ||
!IS_ALIGNED(pci_addr, window_size)) {
--
2.7.4