From: David Daney <david.daney@xxxxxxxxxx>
The 32-bit addressing modes in the I/O and Prefetchable Memory
registers are required to be read-only. Since the underlying access
method allows them to be set, we must emulate their read-only nature
and always set them.
Signed-off-by: David Daney <david.daney@xxxxxxxxxx>
---
drivers/pci/host/pci-thunder-pem.c | 42 ++++++++++++++++++++++++++++++--------
1 file changed, 34 insertions(+), 8 deletions(-)
diff --git a/drivers/pci/host/pci-thunder-pem.c b/drivers/pci/host/pci-thunder-pem.c
index cabb92a..196adf6 100644
--- a/drivers/pci/host/pci-thunder-pem.c
+++ b/drivers/pci/host/pci-thunder-pem.c
@@ -153,11 +153,11 @@ static int thunder_pem_config_read(struct pci_bus *bus, unsigned int devfn,
* reserved bits, this makes the code simpler and is OK as the bits
* are not affected by writing zeros to them.
*/
-static u32 thunder_pem_bridge_w1c_bits(int where)
+static u32 thunder_pem_bridge_w1c_bits(u64 where_aligned)
{
u32 w1c_bits = 0;
- switch (where & ~3) {
+ switch (where_aligned) {
case 0x04: /* Command/Status */
case 0x1c: /* Base and I/O Limit/Secondary Status */
w1c_bits = 0xff000000;
@@ -184,12 +184,34 @@ static u32 thunder_pem_bridge_w1c_bits(int where)
return w1c_bits;
}
+/* Some bits must be written to one so they appear to be read-only. */
+static u32 thunder_pem_bridge_w1_bits(u64 where_aligned)
+{
+ u32 w1_bits;
+
+ switch (where_aligned) {
+ case 0x1c: /* I/O Base / I/O Limit, Secondary Status*/
+ /* Force 32-bit I/O addressing. */
+ w1_bits = 0x0101;
+ break;
+ case 0x24: /* Prefetchable Memory Base / Prefetchable Memory Limit */
+ /* Force 64-bit addressing */
+ w1_bits = 0x00010001;
+ break;
+ default:
+ w1_bits = 0;
+ break;
+ }
+ return w1_bits;
+}
+
static int thunder_pem_bridge_write(struct pci_bus *bus, unsigned int devfn,
int where, int size, u32 val)
{
struct gen_pci *pci = bus->sysdata;
struct thunder_pem_pci *pem_pci;
u64 write_val, read_val;
+ u64 where_aligned = where & ~3ull;
u32 mask = 0;
pem_pci = container_of(pci, struct thunder_pem_pci, gen_pci);
@@ -205,8 +227,7 @@ static int thunder_pem_bridge_write(struct pci_bus *bus, unsigned int devfn,
*/
switch (size) {
case 1:
- read_val = where & ~3ull;
- writeq(read_val, pem_pci->pem_reg_base + PEM_CFG_RD);
+ writeq(where_aligned, pem_pci->pem_reg_base + PEM_CFG_RD);
read_val = readq(pem_pci->pem_reg_base + PEM_CFG_RD);
read_val >>= 32;
mask = ~(0xff << (8 * (where & 3)));
@@ -215,8 +236,7 @@ static int thunder_pem_bridge_write(struct pci_bus *bus, unsigned int devfn,
val |= (u32)read_val;
break;
case 2:
- read_val = where & ~3ull;
- writeq(read_val, pem_pci->pem_reg_base + PEM_CFG_RD);
+ writeq(where_aligned, pem_pci->pem_reg_base + PEM_CFG_RD);
read_val = readq(pem_pci->pem_reg_base + PEM_CFG_RD);
read_val >>= 32;
mask = ~(0xffff << (8 * (where & 3)));
@@ -244,11 +264,17 @@ static int thunder_pem_bridge_write(struct pci_bus *bus, unsigned int devfn,
}
/*
+ * Some bits must be read-only with value of one. Since the
+ * access method allows these to be cleared if a zero is
+ * written, force them to one before writing.
+ */
+ val |= thunder_pem_bridge_w1_bits(where_aligned);
+
+ /*
* Low order bits are the config address, the high order 32
* bits are the data to be written.
*/
- write_val = where & ~3ull;
- write_val |= (((u64)val) << 32);
+ write_val = (((u64)val) << 32) | where_aligned;
writeq(write_val, pem_pci->pem_reg_base + PEM_CFG_WR);
return PCIBIOS_SUCCESSFUL;
}
--
1.8.3.1
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