linux/arch/powerpc/boot/cpm-serial.c
Scott Wood 15f8c604a7 [POWERPC] cpm: Describe multi-user ram in its own device node.
The way the current CPM binding describes available multi-user (a.k.a.
dual-ported) RAM doesn't work well when there are multiple free regions,
and it doesn't work at all if the region doesn't begin at the start of
the muram area (as the hardware needs to be programmed with offsets into
this area).  The latter situation can happen with SMC UARTs on CPM2, as its
parameter RAM is relocatable, u-boot puts it at zero, and the kernel doesn't
support moving it.

It is now described with a muram node, similar to QE.  The current CPM
binding is sufficiently recent (i.e. never appeared in an official release)
that compatibility with existing device trees is not an issue.

The code supporting the new binding is shared between cpm1 and cpm2, rather
than remain separated.  QE should be able to use this code as well, once
minor fixes are made to its device trees.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2007-10-04 15:47:05 -05:00

270 lines
4.7 KiB
C

/*
* CPM serial console support.
*
* Copyright 2007 Freescale Semiconductor, Inc.
* Author: Scott Wood <scottwood@freescale.com>
*
* It is assumed that the firmware (or the platform file) has already set
* up the port.
*/
#include "types.h"
#include "io.h"
#include "ops.h"
struct cpm_scc {
u32 gsmrl;
u32 gsmrh;
u16 psmr;
u8 res1[2];
u16 todr;
u16 dsr;
u16 scce;
u8 res2[2];
u16 sccm;
u8 res3;
u8 sccs;
u8 res4[8];
};
struct cpm_smc {
u8 res1[2];
u16 smcmr;
u8 res2[2];
u8 smce;
u8 res3[3];
u8 smcm;
u8 res4[5];
};
struct cpm_param {
u16 rbase;
u16 tbase;
u8 rfcr;
u8 tfcr;
};
struct cpm_bd {
u16 sc; /* Status and Control */
u16 len; /* Data length in buffer */
u8 *addr; /* Buffer address in host memory */
};
static void *cpcr;
static struct cpm_param *param;
static struct cpm_smc *smc;
static struct cpm_scc *scc;
struct cpm_bd *tbdf, *rbdf;
static u32 cpm_cmd;
static u8 *muram_start;
static u32 muram_offset;
static void (*do_cmd)(int op);
static void (*enable_port)(void);
static void (*disable_port)(void);
#define CPM_CMD_STOP_TX 4
#define CPM_CMD_RESTART_TX 6
#define CPM_CMD_INIT_RX_TX 0
static void cpm1_cmd(int op)
{
while (in_be16(cpcr) & 1)
;
out_be16(cpcr, (op << 8) | cpm_cmd | 1);
while (in_be16(cpcr) & 1)
;
}
static void cpm2_cmd(int op)
{
while (in_be32(cpcr) & 0x10000)
;
out_be32(cpcr, op | cpm_cmd | 0x10000);
while (in_be32(cpcr) & 0x10000)
;
}
static void smc_disable_port(void)
{
do_cmd(CPM_CMD_STOP_TX);
out_be16(&smc->smcmr, in_be16(&smc->smcmr) & ~3);
}
static void scc_disable_port(void)
{
do_cmd(CPM_CMD_STOP_TX);
out_be32(&scc->gsmrl, in_be32(&scc->gsmrl) & ~0x30);
}
static void smc_enable_port(void)
{
out_be16(&smc->smcmr, in_be16(&smc->smcmr) | 3);
do_cmd(CPM_CMD_RESTART_TX);
}
static void scc_enable_port(void)
{
out_be32(&scc->gsmrl, in_be32(&scc->gsmrl) | 0x30);
do_cmd(CPM_CMD_RESTART_TX);
}
static int cpm_serial_open(void)
{
disable_port();
out_8(&param->rfcr, 0x10);
out_8(&param->tfcr, 0x10);
rbdf = (struct cpm_bd *)muram_start;
rbdf->addr = (u8 *)(rbdf + 2);
rbdf->sc = 0xa000;
rbdf->len = 1;
tbdf = rbdf + 1;
tbdf->addr = (u8 *)(rbdf + 2) + 1;
tbdf->sc = 0x2000;
tbdf->len = 1;
sync();
out_be16(&param->rbase, muram_offset);
out_be16(&param->tbase, muram_offset + sizeof(struct cpm_bd));
do_cmd(CPM_CMD_INIT_RX_TX);
enable_port();
return 0;
}
static void cpm_serial_putc(unsigned char c)
{
while (tbdf->sc & 0x8000)
barrier();
sync();
tbdf->addr[0] = c;
eieio();
tbdf->sc |= 0x8000;
}
static unsigned char cpm_serial_tstc(void)
{
barrier();
return !(rbdf->sc & 0x8000);
}
static unsigned char cpm_serial_getc(void)
{
unsigned char c;
while (!cpm_serial_tstc())
;
sync();
c = rbdf->addr[0];
eieio();
rbdf->sc |= 0x8000;
return c;
}
int cpm_console_init(void *devp, struct serial_console_data *scdp)
{
void *reg_virt[2];
int is_smc = 0, is_cpm2 = 0, n;
unsigned long reg_phys;
void *parent, *muram;
if (dt_is_compatible(devp, "fsl,cpm1-smc-uart")) {
is_smc = 1;
} else if (dt_is_compatible(devp, "fsl,cpm2-scc-uart")) {
is_cpm2 = 1;
} else if (dt_is_compatible(devp, "fsl,cpm2-smc-uart")) {
is_cpm2 = 1;
is_smc = 1;
}
if (is_smc) {
enable_port = smc_enable_port;
disable_port = smc_disable_port;
} else {
enable_port = scc_enable_port;
disable_port = scc_disable_port;
}
if (is_cpm2)
do_cmd = cpm2_cmd;
else
do_cmd = cpm1_cmd;
n = getprop(devp, "fsl,cpm-command", &cpm_cmd, 4);
if (n < 4)
return -1;
n = getprop(devp, "virtual-reg", reg_virt, sizeof(reg_virt));
if (n < (int)sizeof(reg_virt)) {
for (n = 0; n < 2; n++) {
if (!dt_xlate_reg(devp, n, &reg_phys, NULL))
return -1;
reg_virt[n] = (void *)reg_phys;
}
}
if (is_smc)
smc = reg_virt[0];
else
scc = reg_virt[0];
param = reg_virt[1];
parent = get_parent(devp);
if (!parent)
return -1;
n = getprop(parent, "virtual-reg", reg_virt, sizeof(reg_virt));
if (n < (int)sizeof(reg_virt)) {
if (!dt_xlate_reg(parent, 0, &reg_phys, NULL))
return -1;
reg_virt[0] = (void *)reg_phys;
}
cpcr = reg_virt[0];
muram = finddevice("/soc/cpm/muram/data");
if (!muram)
return -1;
/* For bootwrapper-compatible device trees, we assume that the first
* entry has at least 18 bytes, and that #address-cells/#data-cells
* is one for both parent and child.
*/
n = getprop(muram, "virtual-reg", reg_virt, sizeof(reg_virt));
if (n < (int)sizeof(reg_virt)) {
if (!dt_xlate_reg(muram, 0, &reg_phys, NULL))
return -1;
reg_virt[0] = (void *)reg_phys;
}
muram_start = reg_virt[0];
n = getprop(muram, "reg", &muram_offset, 4);
if (n < 4)
return -1;
scdp->open = cpm_serial_open;
scdp->putc = cpm_serial_putc;
scdp->getc = cpm_serial_getc;
scdp->tstc = cpm_serial_tstc;
return 0;
}