[PATCHv5 01/13] qemu: make default_write_config use mask table

Michael S. Tsirkin
2009-06-18T13:15:52Z

Change much of hw/pci to use symbolic constants and a table-driven
design: add a mask table with writable bits set and readonly bits unset.
Detect change by comparing original and new registers.

This makes it easy to support capabilities where read-only/writeable
bit layout differs between devices, depending on capabilities present.

As a result, writing a single byte in BAR registers now works as
it should. Writing to upper limit registers in the bridge
also works as it should. Code is also shorter.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
hw/pci.c | 145 ++++++++++++-------------------------------------------------
hw/pci.h | 18 +++++++-
2 files changed, 46 insertions(+), 117 deletions(-)

diff --git a/hw/pci.c b/hw/pci.c
index 0a738db..840986f 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -238,6 +238,17 @@ int pci_assign_devaddr(const char *addr, int *domp, int *busp, unsigned *slotp)
return pci_parse_devaddr(devaddr, domp, busp, slotp);
}

+static void pci_init_mask(PCIDevice *dev)
+{
+ int i;
+ dev->wmask[PCI_CACHE_LINE_SIZE] = 0xff;
+ dev->wmask[PCI_INTERRUPT_LINE] = 0xff;
+ dev->wmask[PCI_COMMAND] = PCI_COMMAND_IO | PCI_COMMAND_MEMORY
+ | PCI_COMMAND_MASTER;
+ for (i = PCI_CONFIG_HEADER_SIZE; i < PCI_CONFIG_SPACE_SIZE; ++i)
+ dev->wmask[i] = 0xff;
+}
+
/* -1 for devfn means auto assign */
static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, PCIBus *bus,
const char *name, int devfn,
@@ -257,6 +268,7 @@ static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, PCIBus *bus,
pstrcpy(pci_dev->name, sizeof(pci_dev->name), name);
memset(pci_dev->irq_state, 0, sizeof(pci_dev->irq_state));
pci_set_default_subsystem_id(pci_dev);
+ pci_init_mask(pci_dev);

if (!config_read)
config_read = pci_default_read_config;
@@ -328,6 +340,7 @@ void pci_register_bar(PCIDevice *pci_dev, int region_num,
{
PCIIORegion *r;
uint32_t addr;
+ uint32_t wmask;

if ((unsigned int)region_num >= PCI_NUM_REGIONS)
return;
@@ -343,12 +356,17 @@ void pci_register_bar(PCIDevice *pci_dev, int region_num,
r->size = size;
r->type = type;
r->map_func = map_func;
+
+ wmask = ~(size - 1);
if (region_num == PCI_ROM_SLOT) {
addr = 0x30;
+ /* ROM enable bit is writeable */
+ wmask |= 1;
} else {
addr = 0x10 + region_num * 4;
}
*(uint32_t *)(pci_dev->config + addr) = cpu_to_le32(type);
+ *(uint32_t *)(pci_dev->wmask + addr) = cpu_to_le32(wmask);
}

static void pci_update_mappings(PCIDevice *d)
@@ -457,118 +475,21 @@ uint32_t pci_default_read_config(PCIDevice *d,
return val;
}

-void pci_default_write_config(PCIDevice *d,
- uint32_t address, uint32_t val, int len)
+void pci_default_write_config(PCIDevice *d, uint32_t addr, uint32_t val, int l)
{
- int can_write, i;
- uint32_t end, addr;
-
- if (len == 4 && ((address >= 0x10 && address < 0x10 + 4 * 6) ||
- (address >= 0x30 && address < 0x34))) {
- PCIIORegion *r;
- int reg;
+ uint8_t orig[PCI_CONFIG_SPACE_SIZE];
+ int i;

- if ( address >= 0x30 ) {
- reg = PCI_ROM_SLOT;
- }else{
- reg = (address - 0x10) >> 2;
- }
- r = &d->io_regions[reg];
- if (r->size == 0)
- goto default_config;
- /* compute the stored value */
- if (reg == PCI_ROM_SLOT) {
- /* keep ROM enable bit */
- val &= (~(r->size - 1)) | 1;
- } else {
- val &= ~(r->size - 1);
- val |= r->type;
- }
- *(uint32_t *)(d->config + address) = cpu_to_le32(val);
- pci_update_mappings(d);
- return;
- }
- default_config:
/* not efficient, but simple */
- addr = address;
- for(i = 0; i < len; i++) {
- /* default read/write accesses */
- switch(d->config[0x0e]) {
- case 0x00:
- case 0x80:
- switch(addr) {
- case 0x00:
- case 0x01:
- case 0x02:
- case 0x03:
- case 0x06:
- case 0x07:
- case 0x08:
- case 0x09:
- case 0x0a:
- case 0x0b:
- case 0x0e:
- case 0x10 ... 0x27: /* base */
- case 0x2c ... 0x2f: /* read-only subsystem ID & vendor ID */
- case 0x30 ... 0x33: /* rom */
- case 0x3d:
- can_write = 0;
- break;
- default:
- can_write = 1;
- break;
- }
- break;
- default:
- case 0x01:
- switch(addr) {
- case 0x00:
- case 0x01:
- case 0x02:
- case 0x03:
- case 0x06:
- case 0x07:
- case 0x08:
- case 0x09:
- case 0x0a:
- case 0x0b:
- case 0x0e:
- case 0x2c ... 0x2f: /* read-only subsystem ID & vendor ID */
- case 0x38 ... 0x3b: /* rom */
- case 0x3d:
- can_write = 0;
- break;
- default:
- can_write = 1;
- break;
- }
- break;
- }
- if (can_write) {
- /* Mask out writes to reserved bits in registers */
- switch (addr) {
- case 0x05:
- val &= ~PCI_COMMAND_RESERVED_MASK_HI;
- break;
- case 0x06:
- val &= ~PCI_STATUS_RESERVED_MASK_LO;
- break;
- case 0x07:
- val &= ~PCI_STATUS_RESERVED_MASK_HI;
- break;
- }
- d->config[addr] = val;
- }
- if (++addr > 0xff)
- break;
- val >>= 8;
+ memcpy(orig, d->config, PCI_CONFIG_SPACE_SIZE);
+ for(i = 0; i < l && addr < PCI_CONFIG_SPACE_SIZE; val >>= 8, ++i, ++addr) {
+ uint8_t wmask = d->wmask[addr];
+ d->config[addr] = (d->config[addr] & ~wmask) | (val & wmask);
}
-
- end = address + len;
- if (end > PCI_COMMAND && address < (PCI_COMMAND + 2)) {
- /* if the command register is modified, we must modify the mappings */
+ if (memcmp(orig + PCI_BASE_ADDRESS_0, d->config + PCI_BASE_ADDRESS_0, 24)
+ || ((orig[PCI_COMMAND] ^ d->config[PCI_COMMAND])
+ & (PCI_COMMAND_MEMORY | PCI_COMMAND_IO)))
pci_update_mappings(d);
- }
}

void pci_data_write(void *opaque, uint32_t addr, uint32_t val, int len)
@@ -841,16 +762,8 @@ static void pci_bridge_write_config(PCIDevice *d,
{
PCIBridge *s = (PCIBridge *)d;

- if (address == 0x19 || (address == 0x18 && len > 1)) {
- if (address == 0x19)
- s->bus->bus_num = val & 0xff;
- else
- s->bus->bus_num = (val >> 8) & 0xff;
-#if defined(DEBUG_PCI)
- printf ("pci-bridge: %s: Assigned bus %d\n", d->name, s->bus->bus_num);
-#endif
- }
pci_default_write_config(d, address, val, len);
+ s->bus->bus_num = d->config[PCI_SECONDARY_BUS];
}

PCIBus *pci_find_bus(int bus_num)
diff --git a/hw/pci.h b/hw/pci.h
index fcca526..44aa61b 100644
--- a/hw/pci.h
+++ b/hw/pci.h
@@ -98,16 +98,24 @@ typedef struct PCIIORegion {
#define PCI_COMMAND 0x04 /* 16 bits */
#define PCI_COMMAND_IO 0x1 /* Enable response in I/O space */
#define PCI_COMMAND_MEMORY 0x2 /* Enable response in Memory space */
+#define PCI_COMMAND_MASTER 0x4 /* Enable bus master */
#define PCI_STATUS 0x06 /* 16 bits */
#define PCI_REVISION_ID 0x08 /* 8 bits */
#define PCI_CLASS_DEVICE 0x0a /* Device class */
+#define PCI_CACHE_LINE_SIZE 0x0c /* 8 bits */
+#define PCI_LATENCY_TIMER 0x0d /* 8 bits */
#define PCI_HEADER_TYPE 0x0e /* 8 bits */
#define PCI_HEADER_TYPE_NORMAL 0
#define PCI_HEADER_TYPE_BRIDGE 1
#define PCI_HEADER_TYPE_CARDBUS 2
#define PCI_HEADER_TYPE_MULTI_FUNCTION 0x80
+#define PCI_BASE_ADDRESS_0 0x10 /* 32 bits */
+#define PCI_PRIMARY_BUS 0x18 /* Primary bus number */
+#define PCI_SECONDARY_BUS 0x19 /* Secondary bus number */
+#define PCI_SEC_STATUS 0x1e /* Secondary status register, only bit 14 used */
#define PCI_SUBSYSTEM_VENDOR_ID 0x2c /* 16 bits */
#define PCI_SUBSYSTEM_ID 0x2e /* 16 bits */
+#define PCI_CAPABILITY_LIST 0x34 /* Offset of first capability list entry */
#define PCI_INTERRUPT_LINE 0x3c /* 8 bits */
#define PCI_INTERRUPT_PIN 0x3d /* 8 bits */
#define PCI_MIN_GNT 0x3e /* 8 bits */
@@ -137,10 +145,18 @@ typedef struct PCIIORegion {

#define PCI_COMMAND_RESERVED_MASK_HI (PCI_COMMAND_RESERVED >> 8)

+/* Size of the standard PCI config header */
+#define PCI_CONFIG_HEADER_SIZE 0x40
+/* Size of the standard PCI config space */
+#define PCI_CONFIG_SPACE_SIZE 0x100
+
struct PCIDevice {
DeviceState qdev;
/* PCI config space */
- uint8_t config[256];
+ uint8_t config[PCI_CONFIG_SPACE_SIZE];
+
+ /* Used to implement R/W bytes */
+ uint8_t wmask[PCI_CONFIG_SPACE_SIZE];

/* the following fields are read only */
PCIBus *bus;
--
1.6.2.2