serial: mpc52xx_uart: re-enable mpc5121 PSC UART support
authorAnatolij Gustschin <agust@denx.de>
Wed, 17 Feb 2010 05:30:03 +0000 (22:30 -0700)
committerGrant Likely <grant.likely@secretlab.ca>
Wed, 17 Feb 2010 05:30:03 +0000 (22:30 -0700)
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>
drivers/serial/mpc52xx_uart.c

index 7ce9e9f..3119fdd 100644 (file)
@@ -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>
@@ -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
@@ -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
@@ -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,
@@ -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);
@@ -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,
@@ -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
 
@@ -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;
 
@@ -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);
 }
@@ -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 */
@@ -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 )                                                */
@@ -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;
@@ -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;
@@ -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;
 }
@@ -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",
@@ -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);
 }