[PATCH v4 02/12] PCI: pci-bridge-emul: Add support for PCIe extended capabilities

Pali Rohár
2022-02-22T15:53:52Z

From: Russell King <rmk+kernel@armlinux.org.uk>

Add support for PCIe extended capabilities, which we just redirect to the
emulating driver.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
[pali: Fix writing new value with W1C bits]
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Behún <kabel@kernel.org>
---
drivers/pci/pci-bridge-emul.c | 77 +++++++++++++++++++++++------------
drivers/pci/pci-bridge-emul.h | 15 +++++++
2 files changed, 67 insertions(+), 25 deletions(-)

diff --git a/drivers/pci/pci-bridge-emul.c b/drivers/pci/pci-bridge-emul.c
index a956408834d6..c4b9837006ff 100644
--- a/drivers/pci/pci-bridge-emul.c
+++ b/drivers/pci/pci-bridge-emul.c
@@ -437,10 +437,16 @@ int pci_bridge_emul_conf_read(struct pci_bridge_emul *bridge, int where,
read_op = bridge->ops->read_pcie;
cfgspace = (__le32 *) &bridge->pcie_conf;
behavior = bridge->pcie_cap_regs_behavior;
- } else {
- /* Beyond our PCIe space */
+ } else if (reg < PCI_CFG_SPACE_SIZE) {
+ /* Rest of PCI space not implemented */
*value = 0;
return PCIBIOS_SUCCESSFUL;
+ } else {
+ /* PCIe extended capability space */
+ reg -= PCI_CFG_SPACE_SIZE;
+ read_op = bridge->ops->read_ext;
+ cfgspace = NULL;
+ behavior = NULL;
}

if (read_op)
@@ -448,15 +454,20 @@ int pci_bridge_emul_conf_read(struct pci_bridge_emul *bridge, int where,
else
ret = PCI_BRIDGE_EMUL_NOT_HANDLED;

- if (ret == PCI_BRIDGE_EMUL_NOT_HANDLED)
- *value = le32_to_cpu(cfgspace[reg / 4]);
+ if (ret == PCI_BRIDGE_EMUL_NOT_HANDLED) {
+ if (cfgspace)
+ *value = le32_to_cpu(cfgspace[reg / 4]);
+ else
+ *value = 0;
+ }

/*
* Make sure we never return any reserved bit with a value
* different from 0.
*/
- *value &= behavior[reg / 4].ro | behavior[reg / 4].rw |
- behavior[reg / 4].w1c;
+ if (behavior)
+ *value &= behavior[reg / 4].ro | behavior[reg / 4].rw |
+ behavior[reg / 4].w1c;

if (size == 1)
*value = (*value >> (8 * (where & 3))) & 0xff;
@@ -502,8 +513,15 @@ int pci_bridge_emul_conf_write(struct pci_bridge_emul *bridge, int where,
write_op = bridge->ops->write_pcie;
cfgspace = (__le32 *) &bridge->pcie_conf;
behavior = bridge->pcie_cap_regs_behavior;
- } else {
+ } else if (reg < PCI_CFG_SPACE_SIZE) {
+ /* Rest of PCI space not implemented */
return PCIBIOS_SUCCESSFUL;
+ } else {
+ /* PCIe extended capability space */
+ reg -= PCI_CFG_SPACE_SIZE;
+ write_op = bridge->ops->write_ext;
+ cfgspace = NULL;
+ behavior = NULL;
}

shift = (where & 0x3) * 8;
@@ -517,29 +535,38 @@ int pci_bridge_emul_conf_write(struct pci_bridge_emul *bridge, int where,
else
return PCIBIOS_BAD_REGISTER_NUMBER;

- /* Keep all bits, except the RW bits */
- new = old & (~mask | ~behavior[reg / 4].rw);
+ if (behavior) {
+ /* Keep all bits, except the RW bits */
+ new = old & (~mask | ~behavior[reg / 4].rw);

- /* Update the value of the RW bits */
- new |= (value << shift) & (behavior[reg / 4].rw & mask);
+ /* Update the value of the RW bits */
+ new |= (value << shift) & (behavior[reg / 4].rw & mask);

- /* Clear the W1C bits */
- new &= ~((value << shift) & (behavior[reg / 4].w1c & mask));
+ /* Clear the W1C bits */
+ new &= ~((value << shift) & (behavior[reg / 4].w1c & mask));
+ } else {
+ new = old & ~mask;
+ new |= (value << shift) & mask;
+ }

- /* Save the new value with the cleared W1C bits into the cfgspace */
- cfgspace[reg / 4] = cpu_to_le32(new);
+ if (cfgspace) {
+ /* Save the new value with the cleared W1C bits into the cfgspace */
+ cfgspace[reg / 4] = cpu_to_le32(new);
+ }

- /*
- * Clear the W1C bits not specified by the write mask, so that the
- * write_op() does not clear them.
- */
- new &= ~(behavior[reg / 4].w1c & ~mask);
+ if (behavior) {
+ /*
+ * Clear the W1C bits not specified by the write mask, so that the
+ * write_op() does not clear them.
+ */
+ new &= ~(behavior[reg / 4].w1c & ~mask);

- /*
- * Set the W1C bits specified by the write mask, so that write_op()
- * knows about that they are to be cleared.
- */
- new |= (value << shift) & (behavior[reg / 4].w1c & mask);
+ /*
+ * Set the W1C bits specified by the write mask, so that write_op()
+ * knows about that they are to be cleared.
+ */
+ new |= (value << shift) & (behavior[reg / 4].w1c & mask);
+ }

if (write_op)
write_op(bridge, reg, old, new, mask);
diff --git a/drivers/pci/pci-bridge-emul.h b/drivers/pci/pci-bridge-emul.h
index 4953274cac18..6b5f75b2ad02 100644
--- a/drivers/pci/pci-bridge-emul.h
+++ b/drivers/pci/pci-bridge-emul.h
@@ -90,6 +90,14 @@ struct pci_bridge_emul_ops {
*/
pci_bridge_emul_read_status_t (*read_pcie)(struct pci_bridge_emul *bridge,
int reg, u32 *value);
+
+ /*
+ * Same as ->read_base(), except it is for reading from the
+ * PCIe extended capability configuration space.
+ */
+ pci_bridge_emul_read_status_t (*read_ext)(struct pci_bridge_emul *bridge,
+ int reg, u32 *value);
+
/*
* Called when writing to the regular PCI bridge configuration
* space. old is the current value, new is the new value being
@@ -105,6 +113,13 @@ struct pci_bridge_emul_ops {
*/
void (*write_pcie)(struct pci_bridge_emul *bridge, int reg,
u32 old, u32 new, u32 mask);
+
+ /*
+ * Same as ->write_base(), except it is for writing from the
+ * PCIe extended capability configuration space.
+ */
+ void (*write_ext)(struct pci_bridge_emul *bridge, int reg,
+ u32 old, u32 new, u32 mask);
};

struct pci_bridge_reg_behavior;