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Replace splhigh() with critical_enter()/leave() to ensure we write the

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config mode unlock sequence quickly enough. This likely isn't too critical,
since splhigh() has been a noop for a decade...
This commit is contained in:
Warner Losh 2013-02-21 00:27:51 +00:00
parent 37270a177d
commit 1eb7e5fe85
1 changed files with 30 additions and 13 deletions
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43
sys/dev/ppc/ppc.c
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@ -74,6 +74,22 @@ static void ppcintr(void *arg);
#define DEVTOSOFTC(dev) ((struct ppc_data *)device_get_softc(dev)) #define DEVTOSOFTC(dev) ((struct ppc_data *)device_get_softc(dev))
/*
* We use critical enter/leave for the simple config locking needed to
* detect the devices. We just want to make sure that both of our writes
* happen without someone else also writing to those config registers. Since
* we just do this at startup, Giant keeps multiple threads from executing,
* and critical_enter() then is all that's needed to keep us from being preempted
* during the critical sequences with the hardware.
*
* Note: this doesn't prevent multiple threads from putting the chips into
* config mode, but since we only do that to detect the type at startup the
* extra overhead isn't needed since Giant protects us from multiple entry
* and no other code changes these registers.
*/
#define PPC_CONFIG_LOCK(ppc) critical_enter()
#define PPC_CONFIG_UNLOCK(ppc) critical_leave()
devclass_t ppc_devclass; devclass_t ppc_devclass;
const char ppc_driver_name[] = "ppc"; const char ppc_driver_name[] = "ppc";
@ -689,7 +705,7 @@ ppc_pc873xx_detect(struct ppc_data *ppc, int chipset_mode) /* XXX mode never for
static int static int
ppc_smc37c66xgt_detect(struct ppc_data *ppc, int chipset_mode) ppc_smc37c66xgt_detect(struct ppc_data *ppc, int chipset_mode)
{ {
int s, i; int i;
u_char r; u_char r;
int type = -1; int type = -1;
int csr = SMC66x_CSR; /* initial value is 0x3F0 */ int csr = SMC66x_CSR; /* initial value is 0x3F0 */
@ -702,11 +718,10 @@ ppc_smc37c66xgt_detect(struct ppc_data *ppc, int chipset_mode)
/* /*
* Detection: enter configuration mode and read CRD register. * Detection: enter configuration mode and read CRD register.
*/ */
PPC_CONFIG_LOCK(ppc);
s = splhigh();
outb(csr, SMC665_iCODE); outb(csr, SMC665_iCODE);
outb(csr, SMC665_iCODE); outb(csr, SMC665_iCODE);
splx(s); PPC_CONFIG_UNLOCK(ppc);
outb(csr, 0xd); outb(csr, 0xd);
if (inb(cio) == 0x65) { if (inb(cio) == 0x65) {
@ -715,10 +730,10 @@ ppc_smc37c66xgt_detect(struct ppc_data *ppc, int chipset_mode)
} }
for (i = 0; i < 2; i++) { for (i = 0; i < 2; i++) {
s = splhigh(); PPC_CONFIG_LOCK(ppc);
outb(csr, SMC666_iCODE); outb(csr, SMC666_iCODE);
outb(csr, SMC666_iCODE); outb(csr, SMC666_iCODE);
splx(s); PPC_CONFIG_UNLOCK(ppc);
outb(csr, 0xd); outb(csr, 0xd);
if (inb(cio) == 0x66) { if (inb(cio) == 0x66) {
@ -734,16 +749,20 @@ ppc_smc37c66xgt_detect(struct ppc_data *ppc, int chipset_mode)
/* /*
* If chipset not found, do not continue. * If chipset not found, do not continue.
*/ */
if (type == -1) if (type == -1) {
outb(csr, 0xaa); /* end config mode */
return (-1); return (-1);
}
/* select CR1 */ /* select CR1 */
outb(csr, 0x1); outb(csr, 0x1);
/* read the port's address: bits 0 and 1 of CR1 */ /* read the port's address: bits 0 and 1 of CR1 */
r = inb(cio) & SMC_CR1_ADDR; r = inb(cio) & SMC_CR1_ADDR;
if (port_address[(int)r] != ppc->ppc_base) if (port_address[(int)r] != ppc->ppc_base) {
outb(csr, 0xaa); /* end config mode */
return (-1); return (-1);
}
ppc->ppc_model = type; ppc->ppc_model = type;
@ -881,8 +900,7 @@ ppc_smc37c66xgt_detect(struct ppc_data *ppc, int chipset_mode)
outb(cio, (r | SMC_CR4_EPPTYPE)); outb(cio, (r | SMC_CR4_EPPTYPE));
} }
/* end config mode */ outb(csr, 0xaa); /* end config mode */
outb(csr, 0xaa);
ppc->ppc_type = PPC_TYPE_SMCLIKE; ppc->ppc_type = PPC_TYPE_SMCLIKE;
ppc_smclike_setmode(ppc, chipset_mode); ppc_smclike_setmode(ppc, chipset_mode);
@ -897,13 +915,12 @@ ppc_smc37c66xgt_detect(struct ppc_data *ppc, int chipset_mode)
static int static int
ppc_smc37c935_detect(struct ppc_data *ppc, int chipset_mode) ppc_smc37c935_detect(struct ppc_data *ppc, int chipset_mode)
{ {
int s;
int type = -1; int type = -1;
s = splhigh(); PPC_CONFIG_LOCK(ppc);
outb(SMC935_CFG, 0x55); /* enter config mode */ outb(SMC935_CFG, 0x55); /* enter config mode */
outb(SMC935_CFG, 0x55); outb(SMC935_CFG, 0x55);
splx(s); PPC_CONFIG_UNLOCK(ppc);
outb(SMC935_IND, SMC935_ID); /* check device id */ outb(SMC935_IND, SMC935_ID); /* check device id */
if (inb(SMC935_DAT) == 0x2) if (inb(SMC935_DAT) == 0x2)