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serial: mpc52xx_uart: re-enable mpc5121 PSC UART support
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Currently the support for MPC5121 PSC UART in the mpc52xx_uart
driver is broken (only console pre-initialized by the bootloader
works). Re-enable it now by providing MPC5121 specific ops
for PSCx clock activation, FIFO controller init/uninit and
MPC5121 PSC FIFO shared interrupt handling functions.

Signed-off-by: John Rigby <jcrigby@gmail.com>
Signed-off-by: Anatolij Gustschin <agust@denx.de>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
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Anatolij Gustschin authored and Grant Likely committed Feb 17, 2010
1 parent cf24dae commit 6acc683
Showing 1 changed file with 236 additions and 15 deletions.
251 changes: 236 additions & 15 deletions drivers/serial/mpc52xx_uart.c
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Original file line number Diff line number Diff line change
Expand Up @@ -74,6 +74,7 @@
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/clk.h>

#include <asm/mpc52xx.h>
#include <asm/mpc52xx_psc.h>
Expand Down Expand Up @@ -113,6 +114,7 @@ static void mpc52xx_uart_of_enumerate(void);

/* Forward declaration of the interruption handling routine */
static irqreturn_t mpc52xx_uart_int(int irq, void *dev_id);
static irqreturn_t mpc5xxx_uart_process_int(struct uart_port *port);


/* Simple macro to test if a port is console or not. This one is taken
Expand Down Expand Up @@ -145,6 +147,11 @@ struct psc_ops {
void (*cw_disable_ints)(struct uart_port *port);
void (*cw_restore_ints)(struct uart_port *port);
unsigned long (*getuartclk)(void *p);
int (*clock)(struct uart_port *port, int enable);
int (*fifoc_init)(void);
void (*fifoc_uninit)(void);
void (*get_irq)(struct uart_port *, struct device_node *);
irqreturn_t (*handle_irq)(struct uart_port *port);
};

#ifdef CONFIG_PPC_MPC52xx
Expand Down Expand Up @@ -256,6 +263,18 @@ static unsigned long mpc52xx_getuartclk(void *p)
return mpc5xxx_get_bus_frequency(p) / 2;
}

static void mpc52xx_psc_get_irq(struct uart_port *port, struct device_node *np)
{
port->irqflags = IRQF_DISABLED;
port->irq = irq_of_parse_and_map(np, 0);
}

/* 52xx specific interrupt handler. The caller holds the port lock */
static irqreturn_t mpc52xx_psc_handle_irq(struct uart_port *port)
{
return mpc5xxx_uart_process_int(port);
}

static struct psc_ops mpc52xx_psc_ops = {
.fifo_init = mpc52xx_psc_fifo_init,
.raw_rx_rdy = mpc52xx_psc_raw_rx_rdy,
Expand All @@ -273,14 +292,32 @@ static struct psc_ops mpc52xx_psc_ops = {
.cw_disable_ints = mpc52xx_psc_cw_disable_ints,
.cw_restore_ints = mpc52xx_psc_cw_restore_ints,
.getuartclk = mpc52xx_getuartclk,
.get_irq = mpc52xx_psc_get_irq,
.handle_irq = mpc52xx_psc_handle_irq,
};

#endif /* CONFIG_MPC52xx */

#ifdef CONFIG_PPC_MPC512x
#define FIFO_512x(port) ((struct mpc512x_psc_fifo __iomem *)(PSC(port)+1))

/* PSC FIFO Controller for mpc512x */
struct psc_fifoc {
u32 fifoc_cmd;
u32 fifoc_int;
u32 fifoc_dma;
u32 fifoc_axe;
u32 fifoc_debug;
};

static struct psc_fifoc __iomem *psc_fifoc;
static unsigned int psc_fifoc_irq;

static void mpc512x_psc_fifo_init(struct uart_port *port)
{
/* /32 prescaler */
out_be16(&PSC(port)->mpc52xx_psc_clock_select, 0xdd00);

out_be32(&FIFO_512x(port)->txcmd, MPC512x_PSC_FIFO_RESET_SLICE);
out_be32(&FIFO_512x(port)->txcmd, MPC512x_PSC_FIFO_ENABLE_SLICE);
out_be32(&FIFO_512x(port)->txalarm, 1);
Expand Down Expand Up @@ -393,6 +430,160 @@ static unsigned long mpc512x_getuartclk(void *p)
return mpc5xxx_get_bus_frequency(p);
}

#define DEFAULT_FIFO_SIZE 16

static unsigned int __init get_fifo_size(struct device_node *np,
char *fifo_name)
{
const unsigned int *fp;

fp = of_get_property(np, fifo_name, NULL);
if (fp)
return *fp;

pr_warning("no %s property in %s node, defaulting to %d\n",
fifo_name, np->full_name, DEFAULT_FIFO_SIZE);

return DEFAULT_FIFO_SIZE;
}

#define FIFOC(_base) ((struct mpc512x_psc_fifo __iomem *) \
((u32)(_base) + sizeof(struct mpc52xx_psc)))

/* Init PSC FIFO Controller */
static int __init mpc512x_psc_fifoc_init(void)
{
struct device_node *np;
void __iomem *psc;
unsigned int tx_fifo_size;
unsigned int rx_fifo_size;
int fifobase = 0; /* current fifo address in 32 bit words */

np = of_find_compatible_node(NULL, NULL,
"fsl,mpc5121-psc-fifo");
if (!np) {
pr_err("%s: Can't find FIFOC node\n", __func__);
return -ENODEV;
}

psc_fifoc = of_iomap(np, 0);
if (!psc_fifoc) {
pr_err("%s: Can't map FIFOC\n", __func__);
return -ENODEV;
}

psc_fifoc_irq = irq_of_parse_and_map(np, 0);
of_node_put(np);
if (psc_fifoc_irq == NO_IRQ) {
pr_err("%s: Can't get FIFOC irq\n", __func__);
iounmap(psc_fifoc);
return -ENODEV;
}

for_each_compatible_node(np, NULL, "fsl,mpc5121-psc-uart") {
tx_fifo_size = get_fifo_size(np, "fsl,tx-fifo-size");
rx_fifo_size = get_fifo_size(np, "fsl,rx-fifo-size");

/* size in register is in 4 byte units */
tx_fifo_size /= 4;
rx_fifo_size /= 4;
if (!tx_fifo_size)
tx_fifo_size = 1;
if (!rx_fifo_size)
rx_fifo_size = 1;

psc = of_iomap(np, 0);
if (!psc) {
pr_err("%s: Can't map %s device\n",
__func__, np->full_name);
continue;
}

/* FIFO space is 4KiB, check if requested size is available */
if ((fifobase + tx_fifo_size + rx_fifo_size) > 0x1000) {
pr_err("%s: no fifo space available for %s\n",
__func__, np->full_name);
iounmap(psc);
/*
* chances are that another device requests less
* fifo space, so we continue.
*/
continue;
}
/* set tx and rx fifo size registers */
out_be32(&FIFOC(psc)->txsz, (fifobase << 16) | tx_fifo_size);
fifobase += tx_fifo_size;
out_be32(&FIFOC(psc)->rxsz, (fifobase << 16) | rx_fifo_size);
fifobase += rx_fifo_size;

/* reset and enable the slices */
out_be32(&FIFOC(psc)->txcmd, 0x80);
out_be32(&FIFOC(psc)->txcmd, 0x01);
out_be32(&FIFOC(psc)->rxcmd, 0x80);
out_be32(&FIFOC(psc)->rxcmd, 0x01);

iounmap(psc);
}

return 0;
}

static void __exit mpc512x_psc_fifoc_uninit(void)
{
iounmap(psc_fifoc);
}

/* 512x specific interrupt handler. The caller holds the port lock */
static irqreturn_t mpc512x_psc_handle_irq(struct uart_port *port)
{
unsigned long fifoc_int;
int psc_num;

/* Read pending PSC FIFOC interrupts */
fifoc_int = in_be32(&psc_fifoc->fifoc_int);

/* Check if it is an interrupt for this port */
psc_num = (port->mapbase & 0xf00) >> 8;
if (test_bit(psc_num, &fifoc_int) ||
test_bit(psc_num + 16, &fifoc_int))
return mpc5xxx_uart_process_int(port);

return IRQ_NONE;
}

static int mpc512x_psc_clock(struct uart_port *port, int enable)
{
struct clk *psc_clk;
int psc_num;
char clk_name[10];

if (uart_console(port))
return 0;

psc_num = (port->mapbase & 0xf00) >> 8;
snprintf(clk_name, sizeof(clk_name), "psc%d_clk", psc_num);
psc_clk = clk_get(port->dev, clk_name);
if (IS_ERR(psc_clk)) {
dev_err(port->dev, "Failed to get PSC clock entry!\n");
return -ENODEV;
}

dev_dbg(port->dev, "%s %sable\n", clk_name, enable ? "en" : "dis");

if (enable)
clk_enable(psc_clk);
else
clk_disable(psc_clk);

return 0;
}

static void mpc512x_psc_get_irq(struct uart_port *port, struct device_node *np)
{
port->irqflags = IRQF_SHARED;
port->irq = psc_fifoc_irq;
}

static struct psc_ops mpc512x_psc_ops = {
.fifo_init = mpc512x_psc_fifo_init,
.raw_rx_rdy = mpc512x_psc_raw_rx_rdy,
Expand All @@ -410,6 +601,11 @@ static struct psc_ops mpc512x_psc_ops = {
.cw_disable_ints = mpc512x_psc_cw_disable_ints,
.cw_restore_ints = mpc512x_psc_cw_restore_ints,
.getuartclk = mpc512x_getuartclk,
.clock = mpc512x_psc_clock,
.fifoc_init = mpc512x_psc_fifoc_init,
.fifoc_uninit = mpc512x_psc_fifoc_uninit,
.get_irq = mpc512x_psc_get_irq,
.handle_irq = mpc512x_psc_handle_irq,
};
#endif

Expand Down Expand Up @@ -519,10 +715,15 @@ mpc52xx_uart_startup(struct uart_port *port)
struct mpc52xx_psc __iomem *psc = PSC(port);
int ret;

if (psc_ops->clock) {
ret = psc_ops->clock(port, 1);
if (ret)
return ret;
}

/* Request IRQ */
ret = request_irq(port->irq, mpc52xx_uart_int,
IRQF_DISABLED | IRQF_SAMPLE_RANDOM,
"mpc52xx_psc_uart", port);
port->irqflags, "mpc52xx_psc_uart", port);
if (ret)
return ret;

Expand Down Expand Up @@ -553,6 +754,9 @@ mpc52xx_uart_shutdown(struct uart_port *port)
port->read_status_mask = 0;
out_be16(&psc->mpc52xx_psc_imr, port->read_status_mask);

if (psc_ops->clock)
psc_ops->clock(port, 0);

/* Release interrupt */
free_irq(port->irq, port);
}
Expand Down Expand Up @@ -851,15 +1055,12 @@ mpc52xx_uart_int_tx_chars(struct uart_port *port)
}

static irqreturn_t
mpc52xx_uart_int(int irq, void *dev_id)
mpc5xxx_uart_process_int(struct uart_port *port)
{
struct uart_port *port = dev_id;
unsigned long pass = ISR_PASS_LIMIT;
unsigned int keepgoing;
u8 status;

spin_lock(&port->lock);

/* While we have stuff to do, we continue */
do {
/* If we don't find anything to do, we stop */
Expand All @@ -886,11 +1087,23 @@ mpc52xx_uart_int(int irq, void *dev_id)

} while (keepgoing);

spin_unlock(&port->lock);

return IRQ_HANDLED;
}

static irqreturn_t
mpc52xx_uart_int(int irq, void *dev_id)
{
struct uart_port *port = dev_id;
irqreturn_t ret;

spin_lock(&port->lock);

ret = psc_ops->handle_irq(port);

spin_unlock(&port->lock);

return ret;
}

/* ======================================================================== */
/* Console ( if applicable ) */
Expand Down Expand Up @@ -1152,7 +1365,7 @@ mpc52xx_uart_of_probe(struct of_device *op, const struct of_device_id *match)
return -EINVAL;
}

port->irq = irq_of_parse_and_map(op->node, 0);
psc_ops->get_irq(port, op->node);
if (port->irq == NO_IRQ) {
dev_dbg(&op->dev, "Could not get irq\n");
return -EINVAL;
Expand All @@ -1163,10 +1376,8 @@ mpc52xx_uart_of_probe(struct of_device *op, const struct of_device_id *match)

/* Add the port to the uart sub-system */
ret = uart_add_one_port(&mpc52xx_uart_driver, port);
if (ret) {
irq_dispose_mapping(port->irq);
if (ret)
return ret;
}

dev_set_drvdata(&op->dev, (void *)port);
return 0;
Expand All @@ -1178,10 +1389,8 @@ mpc52xx_uart_of_remove(struct of_device *op)
struct uart_port *port = dev_get_drvdata(&op->dev);
dev_set_drvdata(&op->dev, NULL);

if (port) {
if (port)
uart_remove_one_port(&mpc52xx_uart_driver, port);
irq_dispose_mapping(port->irq);
}

return 0;
}
Expand Down Expand Up @@ -1288,6 +1497,15 @@ mpc52xx_uart_init(void)

mpc52xx_uart_of_enumerate();

/*
* Map the PSC FIFO Controller and init if on MPC512x.
*/
if (psc_ops->fifoc_init) {
ret = psc_ops->fifoc_init();
if (ret)
return ret;
}

ret = of_register_platform_driver(&mpc52xx_uart_of_driver);
if (ret) {
printk(KERN_ERR "%s: of_register_platform_driver failed (%i)\n",
Expand All @@ -1302,6 +1520,9 @@ mpc52xx_uart_init(void)
static void __exit
mpc52xx_uart_exit(void)
{
if (psc_ops->fifoc_uninit)
psc_ops->fifoc_uninit();

of_unregister_platform_driver(&mpc52xx_uart_of_driver);
uart_unregister_driver(&mpc52xx_uart_driver);
}
Expand Down

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