[PATCH 05/10] iommu/ipmmu-vmsa: Calculate context registers' offset instead of a macro

[Oleksandr Tyshchenko <olekstysh@xxxxxxxxx>]

From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>

This is a non-verbatim port of corresponding Linux upsteam commit:
3dc28d9f59eaae41461542b27afe70339347ebb3

Original commit message:
 commit 3dc28d9f59eaae41461542b27afe70339347ebb3
 Author: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
 Date:   Wed Nov 6 11:35:48 2019 +0900

  iommu/ipmmu-vmsa: Calculate context registers' offset instead of a macro

  Since we will have changed memory mapping of the IPMMU in the future,
  this patch uses ipmmu_features values instead of a macro to
  calculate context registers offset. No behavior change.

  Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
  Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
  Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
  Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>

**********

This is a prereq work needed to add support for S4 series easily
in the future.

Almost the same change as original commit makes, but without updating
struct ipmmu_features_default which Xen driver doesn't have (there is
no support of old Arm32 based Gen2 SoCs).

No change in behavior.

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
---
 xen/drivers/passthrough/arm/ipmmu-vmsa.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/xen/drivers/passthrough/arm/ipmmu-vmsa.c 
b/xen/drivers/passthrough/arm/ipmmu-vmsa.c
index 369be4c..ca33456 100644
--- a/xen/drivers/passthrough/arm/ipmmu-vmsa.c
+++ b/xen/drivers/passthrough/arm/ipmmu-vmsa.c
@@ -109,6 +109,8 @@ struct ipmmu_vmsa_xen_device {
 struct ipmmu_features {
     unsigned int number_of_contexts;
     unsigned int num_utlbs;
+    unsigned int ctx_offset_base;
+    unsigned int ctx_offset_stride;
 };
 
 /* Root/Cache IPMMU device's information */
@@ -167,8 +169,6 @@ static DEFINE_SPINLOCK(ipmmu_devices_lock);
 #define TLB_LOOP_TIMEOUT    100 /* 100us */
 
 /* Registers Definition */
-#define IM_CTX_SIZE    0x40
-
 #define IMCTR                0x0000
 /*
  * This field is implemented in IPMMU-MM only. So, can be set for
@@ -315,7 +315,8 @@ static void ipmmu_write(struct ipmmu_vmsa_device *mmu, 
uint32_t offset,
 static unsigned int ipmmu_ctx_reg(struct ipmmu_vmsa_device *mmu,
                                   unsigned int context_id, uint32_t reg)
 {
-    return context_id * IM_CTX_SIZE + reg;
+    return mmu->features->ctx_offset_base +
+        context_id * mmu->features->ctx_offset_stride + reg;
 }
 
 static uint32_t ipmmu_ctx_read(struct ipmmu_vmsa_device *mmu,
@@ -735,6 +736,8 @@ static int ipmmu_init_platform_device(struct device *dev,
 static const struct ipmmu_features ipmmu_features_rcar_gen3 = {
     .number_of_contexts = 8,
     .num_utlbs = 48,
+    .ctx_offset_base = 0,
+    .ctx_offset_stride = 0x40,
 };
 
 static void ipmmu_device_reset(struct ipmmu_vmsa_device *mmu)
-- 
2.7.4