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path: root/drivers/tty/serial/8250/8250_omap.c
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Diffstat (limited to 'drivers/tty/serial/8250/8250_omap.c')
-rw-r--r--drivers/tty/serial/8250/8250_omap.c147
1 files changed, 109 insertions, 38 deletions
diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
index d75a66c72750..826c5c4a2103 100644
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -16,6 +16,7 @@
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/of.h>
+#include <linux/of_device.h>
#include <linux/of_gpio.h>
#include <linux/of_irq.h>
#include <linux/delay.h>
@@ -32,6 +33,11 @@
#define UART_ERRATA_i202_MDR1_ACCESS (1 << 0)
#define OMAP_UART_WER_HAS_TX_WAKEUP (1 << 1)
#define OMAP_DMA_TX_KICK (1 << 2)
+/*
+ * See Advisory 21 in AM437x errata SPRZ408B, updated April 2015.
+ * The same errata is applicable to AM335x and DRA7x processors too.
+ */
+#define UART_ERRATA_CLOCK_DISABLE (1 << 3)
#define OMAP_UART_FCR_RX_TRIG 6
#define OMAP_UART_FCR_TX_TRIG 4
@@ -53,6 +59,12 @@
#define OMAP_UART_MVR_MAJ_SHIFT 8
#define OMAP_UART_MVR_MIN_MASK 0x3f
+/* SYSC register bitmasks */
+#define OMAP_UART_SYSC_SOFTRESET (1 << 1)
+
+/* SYSS register bitmasks */
+#define OMAP_UART_SYSS_RESETDONE (1 << 0)
+
#define UART_TI752_TLR_TX 0
#define UART_TI752_TLR_RX 4
@@ -100,6 +112,7 @@ struct omap8250_priv {
struct work_struct qos_work;
struct uart_8250_dma omap8250_dma;
spinlock_t rx_dma_lock;
+ bool rx_dma_broken;
};
static u32 uart_read(struct uart_8250_port *up, u32 reg)
@@ -232,6 +245,15 @@ static void omap8250_update_scr(struct uart_8250_port *up,
serial_out(up, UART_OMAP_SCR, priv->scr);
}
+static void omap8250_update_mdr1(struct uart_8250_port *up,
+ struct omap8250_priv *priv)
+{
+ if (priv->habit & UART_ERRATA_i202_MDR1_ACCESS)
+ omap_8250_mdr1_errataset(up, priv);
+ else
+ serial_out(up, UART_OMAP_MDR1, priv->mdr1);
+}
+
static void omap8250_restore_regs(struct uart_8250_port *up)
{
struct omap8250_priv *priv = up->port.private_data;
@@ -282,11 +304,9 @@ static void omap8250_restore_regs(struct uart_8250_port *up)
serial_out(up, UART_XOFF1, priv->xoff);
serial_out(up, UART_LCR, up->lcr);
- /* need mode A for FCR */
- if (priv->habit & UART_ERRATA_i202_MDR1_ACCESS)
- omap_8250_mdr1_errataset(up, priv);
- else
- serial_out(up, UART_OMAP_MDR1, priv->mdr1);
+
+ omap8250_update_mdr1(up, priv);
+
up->port.ops->set_mctrl(&up->port, up->port.mctrl);
}
@@ -428,12 +448,9 @@ static void omap_8250_set_termios(struct uart_port *port,
priv->efr |= UART_EFR_CTS;
} else if (up->port.flags & UPF_SOFT_FLOW) {
/*
- * IXON Flag:
- * Enable XON/XOFF flow control on input.
- * Receiver compares XON1, XOFF1.
+ * OMAP rx s/w flow control is borked; the transmitter remains
+ * stuck off even if rx flow control is subsequently disabled
*/
- if (termios->c_iflag & IXON)
- priv->efr |= OMAP_UART_SW_RX;
/*
* IXOFF Flag:
@@ -444,15 +461,6 @@ static void omap_8250_set_termios(struct uart_port *port,
up->port.status |= UPSTAT_AUTOXOFF;
priv->efr |= OMAP_UART_SW_TX;
}
-
- /*
- * IXANY Flag:
- * Enable any character to restart output.
- * Operation resumes after receiving any
- * character after recognition of the XOFF character
- */
- if (termios->c_iflag & IXANY)
- up->mcr |= UART_MCR_XONANY;
}
omap8250_restore_regs(up);
@@ -530,14 +538,14 @@ static void omap_serial_fill_features_erratas(struct uart_8250_port *up,
switch (revision) {
case OMAP_UART_REV_46:
- priv->habit = UART_ERRATA_i202_MDR1_ACCESS;
+ priv->habit |= UART_ERRATA_i202_MDR1_ACCESS;
break;
case OMAP_UART_REV_52:
- priv->habit = UART_ERRATA_i202_MDR1_ACCESS |
+ priv->habit |= UART_ERRATA_i202_MDR1_ACCESS |
OMAP_UART_WER_HAS_TX_WAKEUP;
break;
case OMAP_UART_REV_63:
- priv->habit = UART_ERRATA_i202_MDR1_ACCESS |
+ priv->habit |= UART_ERRATA_i202_MDR1_ACCESS |
OMAP_UART_WER_HAS_TX_WAKEUP;
break;
default:
@@ -754,6 +762,7 @@ static void omap_8250_rx_dma_flush(struct uart_8250_port *p)
struct omap8250_priv *priv = p->port.private_data;
struct uart_8250_dma *dma = p->dma;
unsigned long flags;
+ int ret;
spin_lock_irqsave(&priv->rx_dma_lock, flags);
@@ -762,7 +771,9 @@ static void omap_8250_rx_dma_flush(struct uart_8250_port *p)
return;
}
- dmaengine_pause(dma->rxchan);
+ ret = dmaengine_pause(dma->rxchan);
+ if (WARN_ON_ONCE(ret))
+ priv->rx_dma_broken = true;
spin_unlock_irqrestore(&priv->rx_dma_lock, flags);
@@ -806,6 +817,9 @@ static int omap_8250_rx_dma(struct uart_8250_port *p, unsigned int iir)
break;
}
+ if (priv->rx_dma_broken)
+ return -EINVAL;
+
spin_lock_irqsave(&priv->rx_dma_lock, flags);
if (dma->rx_running)
@@ -1054,6 +1068,20 @@ static int omap8250_no_handle_irq(struct uart_port *port)
return 0;
}
+static const u8 am3352_habit = OMAP_DMA_TX_KICK | UART_ERRATA_CLOCK_DISABLE;
+static const u8 am4372_habit = UART_ERRATA_CLOCK_DISABLE;
+
+static const struct of_device_id omap8250_dt_ids[] = {
+ { .compatible = "ti,omap2-uart" },
+ { .compatible = "ti,omap3-uart" },
+ { .compatible = "ti,omap4-uart" },
+ { .compatible = "ti,am3352-uart", .data = &am3352_habit, },
+ { .compatible = "ti,am4372-uart", .data = &am4372_habit, },
+ { .compatible = "ti,dra742-uart", .data = &am4372_habit, },
+ {},
+};
+MODULE_DEVICE_TABLE(of, omap8250_dt_ids);
+
static int omap8250_probe(struct platform_device *pdev)
{
struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -1118,11 +1146,17 @@ static int omap8250_probe(struct platform_device *pdev)
up.port.unthrottle = omap_8250_unthrottle;
if (pdev->dev.of_node) {
+ const struct of_device_id *id;
+
ret = of_alias_get_id(pdev->dev.of_node, "serial");
of_property_read_u32(pdev->dev.of_node, "clock-frequency",
&up.port.uartclk);
priv->wakeirq = irq_of_parse_and_map(pdev->dev.of_node, 1);
+
+ id = of_match_device(of_match_ptr(omap8250_dt_ids), &pdev->dev);
+ if (id && id->data)
+ priv->habit |= *(u8 *)id->data;
} else {
ret = pdev->id;
}
@@ -1180,6 +1214,11 @@ static int omap8250_probe(struct platform_device *pdev)
if (of_machine_is_compatible("ti,am33xx"))
priv->habit |= OMAP_DMA_TX_KICK;
+ /*
+ * pause is currently not supported atleast on omap-sdma
+ * and edma on most earlier kernels.
+ */
+ priv->rx_dma_broken = true;
}
}
#endif
@@ -1257,17 +1296,46 @@ static int omap8250_lost_context(struct uart_8250_port *up)
{
u32 val;
- val = serial_in(up, UART_OMAP_MDR1);
+ val = serial_in(up, UART_OMAP_SCR);
/*
- * If we lose context, then MDR1 is set to its reset value which is
- * UART_OMAP_MDR1_DISABLE. After set_termios() we set it either to 13x
- * or 16x but never to disable again.
+ * If we lose context, then SCR is set to its reset value of zero.
+ * After set_termios() we set bit 3 of SCR (TX_EMPTY_CTL_IT) to 1,
+ * among other bits, to never set the register back to zero again.
*/
- if (val == UART_OMAP_MDR1_DISABLE)
+ if (!val)
return 1;
return 0;
}
+/* TODO: in future, this should happen via API in drivers/reset/ */
+static int omap8250_soft_reset(struct device *dev)
+{
+ struct omap8250_priv *priv = dev_get_drvdata(dev);
+ struct uart_8250_port *up = serial8250_get_port(priv->line);
+ int timeout = 100;
+ int sysc;
+ int syss;
+
+ sysc = serial_in(up, UART_OMAP_SYSC);
+
+ /* softreset the UART */
+ sysc |= OMAP_UART_SYSC_SOFTRESET;
+ serial_out(up, UART_OMAP_SYSC, sysc);
+
+ /* By experiments, 1us enough for reset complete on AM335x */
+ do {
+ udelay(1);
+ syss = serial_in(up, UART_OMAP_SYSS);
+ } while (--timeout && !(syss & OMAP_UART_SYSS_RESETDONE));
+
+ if (!timeout) {
+ dev_err(dev, "timed out waiting for reset done\n");
+ return -ETIMEDOUT;
+ }
+
+ return 0;
+}
+
static int omap8250_runtime_suspend(struct device *dev)
{
struct omap8250_priv *priv = dev_get_drvdata(dev);
@@ -1285,7 +1353,18 @@ static int omap8250_runtime_suspend(struct device *dev)
return -EBUSY;
}
- if (up->dma)
+ if (priv->habit & UART_ERRATA_CLOCK_DISABLE) {
+ int ret;
+
+ ret = omap8250_soft_reset(dev);
+ if (ret)
+ return ret;
+
+ /* Restore to UART mode after reset (for wakeup) */
+ omap8250_update_mdr1(up, priv);
+ }
+
+ if (up->dma && up->dma->rxchan)
omap_8250_rx_dma(up, UART_IIR_RX_TIMEOUT);
priv->latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE;
@@ -1310,7 +1389,7 @@ static int omap8250_runtime_resume(struct device *dev)
if (loss_cntx)
omap8250_restore_regs(up);
- if (up->dma)
+ if (up->dma && up->dma->rxchan)
omap_8250_rx_dma(up, 0);
priv->latency = priv->calc_latency;
@@ -1367,14 +1446,6 @@ static const struct dev_pm_ops omap8250_dev_pm_ops = {
.complete = omap8250_complete,
};
-static const struct of_device_id omap8250_dt_ids[] = {
- { .compatible = "ti,omap2-uart" },
- { .compatible = "ti,omap3-uart" },
- { .compatible = "ti,omap4-uart" },
- {},
-};
-MODULE_DEVICE_TABLE(of, omap8250_dt_ids);
-
static struct platform_driver omap8250_platform_driver = {
.driver = {
.name = "omap8250",
generated by cgit v1.2.3 (git 2.0.4) at 2024-11-02 03:31:51 +0000