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ARM: OMAP2+: UART: Move errata handling from serial.c to omap-serial
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Move the errata handling mechanism from serial.c to omap-serial file
and utilise the same func in driver file.

Errata i202, i291 are moved to be handled with omap-serial
Moving the errata macro from serial.c file to driver header file
as from on errata will be handled in driver file itself.
Corrected errata id from chapter reference 2.15 to errata id i291.

Removed errata and dma_enabled fields from omap_uart_state struct
as they are no more needed with errata handling done within omap-serial.

Signed-off-by: Govindraj.R <govindraj.raja@ti.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kevin Hilman <khilman@ti.com>
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Govindraj.R authored and Kevin Hilman committed Dec 15, 2011
1 parent ec3bebc commit 9473474
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Showing 3 changed files with 102 additions and 74 deletions.
101 changes: 31 additions & 70 deletions arch/arm/mach-omap2/serial.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -42,8 +42,6 @@
#include "control.h"
#include "mux.h"

#define UART_ERRATA_i202_MDR1_ACCESS (0x1 << 1)

/*
* NOTE: By default the serial timeout is disabled as it causes lost characters
* over the serial ports. This means that the UART clocks will stay on until
Expand All @@ -61,59 +59,17 @@ struct omap_uart_state {
void __iomem *wk_st;
void __iomem *wk_en;
u32 wk_mask;
u32 dma_enabled;

int clocked;

struct list_head node;
struct omap_hwmod *oh;
struct platform_device *pdev;

u32 errata;
};

static LIST_HEAD(uart_list);
static u8 num_uarts;

#if defined(CONFIG_PM) && defined(CONFIG_ARCH_OMAP3)

/*
* Work Around for Errata i202 (3430 - 1.12, 3630 - 1.6)
* The access to uart register after MDR1 Access
* causes UART to corrupt data.
*
* Need a delay =
* 5 L4 clock cycles + 5 UART functional clock cycle (@48MHz = ~0.2uS)
* give 10 times as much
*/
static void omap_uart_mdr1_errataset(struct omap_uart_state *uart, u8 mdr1_val,
u8 fcr_val)
{
u8 timeout = 255;

serial_write_reg(uart, UART_OMAP_MDR1, mdr1_val);
udelay(2);
serial_write_reg(uart, UART_FCR, fcr_val | UART_FCR_CLEAR_XMIT |
UART_FCR_CLEAR_RCVR);
/*
* Wait for FIFO to empty: when empty, RX_FIFO_E bit is 0 and
* TX_FIFO_E bit is 1.
*/
while (UART_LSR_THRE != (serial_read_reg(uart, UART_LSR) &
(UART_LSR_THRE | UART_LSR_DR))) {
timeout--;
if (!timeout) {
/* Should *never* happen. we warn and carry on */
dev_crit(&uart->pdev->dev, "Errata i202: timedout %x\n",
serial_read_reg(uart, UART_LSR));
break;
}
udelay(1);
}
}

#endif /* CONFIG_PM && CONFIG_ARCH_OMAP3 */

static inline void omap_uart_enable_clocks(struct omap_uart_state *uart)
{
if (uart->clocked)
Expand Down Expand Up @@ -156,27 +112,6 @@ static void omap_uart_disable_wakeup(struct omap_uart_state *uart)
}
}

static void omap_uart_smart_idle_enable(struct omap_uart_state *uart,
int enable)
{
u8 idlemode;

if (enable) {
/**
* Errata 2.15: [UART]:Cannot Acknowledge Idle Requests
* in Smartidle Mode When Configured for DMA Operations.
*/
if (uart->dma_enabled)
idlemode = HWMOD_IDLEMODE_FORCE;
else
idlemode = HWMOD_IDLEMODE_SMART;
} else {
idlemode = HWMOD_IDLEMODE_NO;
}

omap_hwmod_set_slave_idlemode(uart->oh, idlemode);
}

static void omap_uart_block_sleep(struct omap_uart_state *uart)
{
omap_uart_enable_clocks(uart);
Expand Down Expand Up @@ -267,7 +202,28 @@ static void omap_uart_idle_init(struct omap_uart_state *uart)
}
}

/*
* Errata i291: [UART]:Cannot Acknowledge Idle Requests
* in Smartidle Mode When Configured for DMA Operations.
* WA: configure uart in force idle mode.
*/
static void omap_uart_set_noidle(struct platform_device *pdev)
{
struct omap_device *od = to_omap_device(pdev);

omap_hwmod_set_slave_idlemode(od->hwmods[0], HWMOD_IDLEMODE_NO);
}

static void omap_uart_set_forceidle(struct platform_device *pdev)
{
struct omap_device *od = to_omap_device(pdev);

omap_hwmod_set_slave_idlemode(od->hwmods[0], HWMOD_IDLEMODE_FORCE);
}

#else
static void omap_uart_set_noidle(struct platform_device *pdev) {}
static void omap_uart_set_forceidle(struct platform_device *pdev) {}
static void omap_uart_block_sleep(struct omap_uart_state *uart)
{
/* Needed to enable UART clocks when built without CONFIG_PM */
Expand Down Expand Up @@ -473,13 +429,22 @@ void __init omap_serial_init_port(struct omap_board_data *bdata)
break;

oh = uart->oh;
uart->dma_enabled = 0;
name = DRIVER_NAME;

omap_up.dma_enabled = uart->dma_enabled;
omap_up.uartclk = OMAP24XX_BASE_BAUD * 16;
omap_up.flags = UPF_BOOT_AUTOCONF;
omap_up.get_context_loss_count = omap_pm_get_dev_context_loss_count;
omap_up.set_forceidle = omap_uart_set_forceidle;
omap_up.set_noidle = omap_uart_set_noidle;

/* Enable the MDR1 Errata i202 for OMAP2430/3xxx/44xx */
if (!cpu_is_omap2420() && !cpu_is_ti816x())
omap_up.errata |= UART_ERRATA_i202_MDR1_ACCESS;

/* Enable DMA Mode Force Idle Errata i291 for omap34xx/3630 */
if (cpu_is_omap34xx() || cpu_is_omap3630())
omap_up.errata |= UART_ERRATA_i291_DMA_FORCEIDLE;

pdata = &omap_up;
pdata_size = sizeof(struct omap_uart_port_info);
Expand Down Expand Up @@ -519,10 +484,6 @@ void __init omap_serial_init_port(struct omap_board_data *bdata)
if (((cpu_is_omap34xx() || cpu_is_omap44xx()) && bdata->pads) ||
(pdata->wk_en && pdata->wk_mask))
device_init_wakeup(&pdev->dev, true);

/* Enable the MDR1 errata for OMAP3 */
if (cpu_is_omap34xx() && !(cpu_is_ti81xx() || cpu_is_am33xx()))
uart->errata |= UART_ERRATA_i202_MDR1_ACCESS;
}

/**
Expand Down
7 changes: 7 additions & 0 deletions arch/arm/plat-omap/include/plat/omap-serial.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -58,12 +58,18 @@

#define MSR_SAVE_FLAGS UART_MSR_ANY_DELTA

#define UART_ERRATA_i202_MDR1_ACCESS BIT(0)
#define UART_ERRATA_i291_DMA_FORCEIDLE BIT(1)

struct omap_uart_port_info {
bool dma_enabled; /* To specify DMA Mode */
unsigned int uartclk; /* UART clock rate */
upf_t flags; /* UPF_* flags */
u32 errata;

int (*get_context_loss_count)(struct device *);
void (*set_forceidle)(struct platform_device *);
void (*set_noidle)(struct platform_device *);
};

struct uart_omap_dma {
Expand Down Expand Up @@ -117,6 +123,7 @@ struct uart_omap_port {
char name[20];
unsigned long port_activity;
u32 context_loss_cnt;
u32 errata;
};

#endif /* __OMAP_SERIAL_H__ */
68 changes: 64 additions & 4 deletions drivers/tty/serial/omap-serial.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -51,6 +51,7 @@ static struct uart_omap_port *ui[OMAP_MAX_HSUART_PORTS];
static void uart_tx_dma_callback(int lch, u16 ch_status, void *data);
static void serial_omap_rx_timeout(unsigned long uart_no);
static int serial_omap_start_rxdma(struct uart_omap_port *up);
static void serial_omap_mdr1_errataset(struct uart_omap_port *up, u8 mdr1);

static inline unsigned int serial_in(struct uart_omap_port *up, int offset)
{
Expand Down Expand Up @@ -808,7 +809,11 @@ serial_omap_set_termios(struct uart_port *port, struct ktermios *termios,

/* Protocol, Baud Rate, and Interrupt Settings */

serial_out(up, UART_OMAP_MDR1, up->mdr1);
if (up->errata & UART_ERRATA_i202_MDR1_ACCESS)
serial_omap_mdr1_errataset(up, up->mdr1);
else
serial_out(up, UART_OMAP_MDR1, up->mdr1);

serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);

up->efr = serial_in(up, UART_EFR);
Expand All @@ -833,7 +838,10 @@ serial_omap_set_termios(struct uart_port *port, struct ktermios *termios,
else
up->mdr1 = UART_OMAP_MDR1_16X_MODE;

serial_out(up, UART_OMAP_MDR1, up->mdr1);
if (up->errata & UART_ERRATA_i202_MDR1_ACCESS)
serial_omap_mdr1_errataset(up, up->mdr1);
else
serial_out(up, UART_OMAP_MDR1, up->mdr1);

/* Hardware Flow Control Configuration */

Expand Down Expand Up @@ -1362,6 +1370,7 @@ static int serial_omap_probe(struct platform_device *pdev)
up->port.flags = omap_up_info->flags;
up->port.uartclk = omap_up_info->uartclk;
up->uart_dma.uart_base = mem->start;
up->errata = omap_up_info->errata;

if (omap_up_info->dma_enabled) {
up->uart_dma.uart_dma_tx = dma_tx->start;
Expand Down Expand Up @@ -1415,9 +1424,47 @@ static int serial_omap_remove(struct platform_device *dev)
return 0;
}

/*
* Work Around for Errata i202 (2430, 3430, 3630, 4430 and 4460)
* The access to uart register after MDR1 Access
* causes UART to corrupt data.
*
* Need a delay =
* 5 L4 clock cycles + 5 UART functional clock cycle (@48MHz = ~0.2uS)
* give 10 times as much
*/
static void serial_omap_mdr1_errataset(struct uart_omap_port *up, u8 mdr1)
{
u8 timeout = 255;

serial_out(up, UART_OMAP_MDR1, mdr1);
udelay(2);
serial_out(up, UART_FCR, up->fcr | UART_FCR_CLEAR_XMIT |
UART_FCR_CLEAR_RCVR);
/*
* Wait for FIFO to empty: when empty, RX_FIFO_E bit is 0 and
* TX_FIFO_E bit is 1.
*/
while (UART_LSR_THRE != (serial_in(up, UART_LSR) &
(UART_LSR_THRE | UART_LSR_DR))) {
timeout--;
if (!timeout) {
/* Should *never* happen. we warn and carry on */
dev_crit(&up->pdev->dev, "Errata i202: timedout %x\n",
serial_in(up, UART_LSR));
break;
}
udelay(1);
}
}

static void serial_omap_restore_context(struct uart_omap_port *up)
{
serial_out(up, UART_OMAP_MDR1, UART_OMAP_MDR1_DISABLE);
if (up->errata & UART_ERRATA_i202_MDR1_ACCESS)
serial_omap_mdr1_errataset(up, UART_OMAP_MDR1_DISABLE);
else
serial_out(up, UART_OMAP_MDR1, UART_OMAP_MDR1_DISABLE);

serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); /* Config B mode */
serial_out(up, UART_EFR, UART_EFR_ECB);
serial_out(up, UART_LCR, 0x0); /* Operational mode */
Expand All @@ -1434,7 +1481,10 @@ static void serial_omap_restore_context(struct uart_omap_port *up)
serial_out(up, UART_OMAP_SCR, up->scr);
serial_out(up, UART_EFR, up->efr);
serial_out(up, UART_LCR, up->lcr);
serial_out(up, UART_OMAP_MDR1, up->mdr1);
if (up->errata & UART_ERRATA_i202_MDR1_ACCESS)
serial_omap_mdr1_errataset(up, up->mdr1);
else
serial_out(up, UART_OMAP_MDR1, up->mdr1);
}

#ifdef CONFIG_PM_RUNTIME
Expand All @@ -1449,6 +1499,11 @@ static int serial_omap_runtime_suspend(struct device *dev)
if (pdata->get_context_loss_count)
up->context_loss_cnt = pdata->get_context_loss_count(dev);

/* Errata i291 */
if (up->use_dma && pdata->set_forceidle &&
(up->errata & UART_ERRATA_i291_DMA_FORCEIDLE))
pdata->set_forceidle(up->pdev);

return 0;
}

Expand All @@ -1464,6 +1519,11 @@ static int serial_omap_runtime_resume(struct device *dev)
if (up->context_loss_cnt != loss_cnt)
serial_omap_restore_context(up);
}

/* Errata i291 */
if (up->use_dma && pdata->set_noidle &&
(up->errata & UART_ERRATA_i291_DMA_FORCEIDLE))
pdata->set_noidle(up->pdev);
}

return 0;
Expand Down

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