adjust_pci_device unconditionally enables both memory and I/O space
access, which may not be necessary. There was also no way to revert
the device back to the original state.
This commit adds two new functions. enable_pci_device gives drivers
finer control over how the PCI device is initialized and
disable_pci_device is the shutdown path counterpart.
Signed-off-by: Ladi Prosek <lpro...@redhat.com>
Suggested-by: Michael S. Tsirkin <m...@redhat.com>
---
src/drivers/bus/pci.c | 41 +++++++++++++++++++++++++++++++++++------
src/include/ipxe/pci.h | 2 ++
2 files changed, 37 insertions(+), 6 deletions(-)
diff --git a/src/drivers/bus/pci.c b/src/drivers/bus/pci.c
index 6fbedd9..bdff2b9 100644
--- a/src/drivers/bus/pci.c
+++ b/src/drivers/bus/pci.c
@@ -143,16 +143,32 @@ static void pci_read_bases ( struct pci_device *pci ) {
*
* @v pci PCI device
*
- * Set device to be a busmaster in case BIOS neglected to do so. Also
- * adjust PCI latency timer to a reasonable value, 32.
+ * Set device to be a busmaster in case BIOS neglected to do so. Enable
+ * both memory and I/O space access. Also adjust PCI latency timer to a
+ * reasonable value, 32.
*/
void adjust_pci_device ( struct pci_device *pci ) {
+ enable_pci_device ( pci,
+ PCI_COMMAND_MASTER | PCI_COMMAND_MEM |
+ PCI_COMMAND_IO );
+}
+
+/**
+ * Enable PCI device
+ *
+ * @v pci PCI device
+ * @v flags PCI command flags to enable
+ * @ret old_flags Original PCI command flags
+ *
+ * Enable device in case BIOS neglected to do so. Also adjust PCI latency
+ * timer to a reasonable value, 32.
+ */
+unsigned enable_pci_device ( struct pci_device *pci, unsigned flags ) {
unsigned short new_command, pci_command;
unsigned char pci_latency;
pci_read_config_word ( pci, PCI_COMMAND, &pci_command );
- new_command = ( pci_command | PCI_COMMAND_MASTER |
- PCI_COMMAND_MEM | PCI_COMMAND_IO );
+ new_command = ( pci_command | flags );
if ( pci_command != new_command ) {
DBGC ( pci, PCI_FMT " device not enabled by BIOS! Updating "
"PCI command %04x->%04x\n",
@@ -160,12 +176,25 @@ void adjust_pci_device ( struct pci_device *pci ) {
pci_write_config_word ( pci, PCI_COMMAND, new_command );
}
- pci_read_config_byte ( pci, PCI_LATENCY_TIMER, &pci_latency);
+ pci_read_config_byte ( pci, PCI_LATENCY_TIMER, &pci_latency );
if ( pci_latency < 32 ) {
DBGC ( pci, PCI_FMT " latency timer is unreasonably low at "
"%d. Setting to 32.\n", PCI_ARGS ( pci ), pci_latency );
- pci_write_config_byte ( pci, PCI_LATENCY_TIMER, 32);
+ pci_write_config_byte ( pci, PCI_LATENCY_TIMER, 32 );
}
+ return pci_command;
+}
+
+/**
+ * Disable PCI device
+ *
+ * @v pci PCI device
+ * @v old_flags Flags to restore, returned from
enable_pci_device
+ *
+ * Restore device to state it had before we enabled it.
+ */
+void disable_pci_device ( struct pci_device *pci, unsigned old_flags ) {
+ pci_write_config_word ( pci, PCI_COMMAND, old_flags );
}
/**
diff --git a/src/include/ipxe/pci.h b/src/include/ipxe/pci.h
index 0c6bc7e..3c613c2 100644
--- a/src/include/ipxe/pci.h
+++ b/src/include/ipxe/pci.h
@@ -278,6 +278,8 @@ struct pci_driver {
PCI_FUNC ( (pci)->busdevfn )
extern void adjust_pci_device ( struct pci_device *pci );
+extern unsigned enable_pci_device ( struct pci_device *pci, unsigned flags );
+extern void disable_pci_device ( struct pci_device *pci, unsigned flags );
extern unsigned long pci_bar_start ( struct pci_device *pci,
unsigned int reg );
extern int pci_read_config ( struct pci_device *pci );
--
2.5.5
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