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author | Krishna Yarlagadda <kyarlagadda@nvidia.com> | 2019-09-04 10:13:06 +0530 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-09-05 10:00:05 +0200 |
commit | d781ec21bae6ff8f9e07682e8947a654484611f5 (patch) | |
tree | c7403f1b109700354d0d6205a712ad5393bf76ee /drivers/tty | |
parent | f04a3cc8d4550463e0c15be59d91177a5def1ca5 (diff) | |
download | linux-d781ec21bae6ff8f9e07682e8947a654484611f5.tar.gz linux-d781ec21bae6ff8f9e07682e8947a654484611f5.tar.bz2 linux-d781ec21bae6ff8f9e07682e8947a654484611f5.zip |
serial: tegra: report clk rate errors
Standard UART controllers support +/-4% baud rate error tolerance.
Tegra186 only supports 0% to +4% error tolerance whereas other Tegra
chips support standard +/-4% rate. Add chip data for knowing error
tolerance level for each soc. Creating new compatible for Tegra194
chip as it supports baud rate error tolerance of -2 to +2%, different
from older chips.
Signed-off-by: Shardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: Krishna Yarlagadda <kyarlagadda@nvidia.com>
Link: https://lore.kernel.org/r/1567572187-29820-12-git-send-email-kyarlagadda@nvidia.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r-- | drivers/tty/serial/serial-tegra.c | 59 |
1 files changed, 57 insertions, 2 deletions
diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c index f970ed7b182d..d0fd41719e70 100644 --- a/drivers/tty/serial/serial-tegra.c +++ b/drivers/tty/serial/serial-tegra.c @@ -89,6 +89,8 @@ struct tegra_uart_chip_data { bool fifo_mode_enable_status; int uart_max_port; int max_dma_burst_bytes; + int error_tolerance_low_range; + int error_tolerance_high_range; }; struct tegra_baud_tolerance { @@ -135,6 +137,8 @@ struct tegra_uart_port { unsigned int rx_bytes_requested; struct tegra_baud_tolerance *baud_tolerance; int n_adjustable_baud_rates; + int required_rate; + int configured_rate; }; static void tegra_uart_start_next_tx(struct tegra_uart_port *tup); @@ -350,6 +354,22 @@ static long tegra_get_tolerance_rate(struct tegra_uart_port *tup, return rate; } +static int tegra_check_rate_in_range(struct tegra_uart_port *tup) +{ + long diff; + + diff = ((long)(tup->configured_rate - tup->required_rate) * 10000) + / tup->required_rate; + if (diff < (tup->cdata->error_tolerance_low_range * 100) || + diff > (tup->cdata->error_tolerance_high_range * 100)) { + dev_err(tup->uport.dev, + "configured baud rate is out of range by %ld", diff); + return -EIO; + } + + return 0; +} + static int tegra_set_baudrate(struct tegra_uart_port *tup, unsigned int baud) { unsigned long rate; @@ -363,6 +383,8 @@ static int tegra_set_baudrate(struct tegra_uart_port *tup, unsigned int baud) if (tup->cdata->support_clk_src_div) { rate = baud * 16; + tup->required_rate = rate; + if (tup->n_adjustable_baud_rates) rate = tegra_get_tolerance_rate(tup, baud, rate); @@ -372,7 +394,11 @@ static int tegra_set_baudrate(struct tegra_uart_port *tup, unsigned int baud) "clk_set_rate() failed for rate %lu\n", rate); return ret; } + tup->configured_rate = clk_get_rate(tup->uart_clk); divisor = 1; + ret = tegra_check_rate_in_range(tup); + if (ret < 0) + return ret; } else { rate = clk_get_rate(tup->uart_clk); divisor = DIV_ROUND_CLOSEST(rate, baud * 16); @@ -991,7 +1017,11 @@ static int tegra_uart_hw_init(struct tegra_uart_port *tup) * enqueued */ tup->lcr_shadow = TEGRA_UART_DEFAULT_LSR; - tegra_set_baudrate(tup, TEGRA_UART_DEFAULT_BAUD); + ret = tegra_set_baudrate(tup, TEGRA_UART_DEFAULT_BAUD); + if (ret < 0) { + dev_err(tup->uport.dev, "Failed to set baud rate\n"); + return ret; + } tup->fcr_shadow |= UART_FCR_DMA_SELECT; tegra_uart_write(tup, tup->fcr_shadow, UART_FCR); @@ -1190,6 +1220,7 @@ static void tegra_uart_set_termios(struct uart_port *u, struct clk *parent_clk = clk_get_parent(tup->uart_clk); unsigned long parent_clk_rate = clk_get_rate(parent_clk); int max_divider = (tup->cdata->support_clk_src_div) ? 0x7FFF : 0xFFFF; + int ret; max_divider *= 16; spin_lock_irqsave(&u->lock, flags); @@ -1262,7 +1293,11 @@ static void tegra_uart_set_termios(struct uart_port *u, parent_clk_rate/max_divider, parent_clk_rate/16); spin_unlock_irqrestore(&u->lock, flags); - tegra_set_baudrate(tup, baud); + ret = tegra_set_baudrate(tup, baud); + if (ret < 0) { + dev_err(tup->uport.dev, "Failed to set baud rate\n"); + return; + } if (tty_termios_baud_rate(termios)) tty_termios_encode_baud_rate(termios, baud, baud); spin_lock_irqsave(&u->lock, flags); @@ -1399,6 +1434,8 @@ static struct tegra_uart_chip_data tegra20_uart_chip_data = { .fifo_mode_enable_status = false, .uart_max_port = 5, .max_dma_burst_bytes = 4, + .error_tolerance_low_range = 0, + .error_tolerance_high_range = 4, }; static struct tegra_uart_chip_data tegra30_uart_chip_data = { @@ -1408,6 +1445,8 @@ static struct tegra_uart_chip_data tegra30_uart_chip_data = { .fifo_mode_enable_status = false, .uart_max_port = 5, .max_dma_burst_bytes = 4, + .error_tolerance_low_range = 0, + .error_tolerance_high_range = 4, }; static struct tegra_uart_chip_data tegra186_uart_chip_data = { @@ -1417,6 +1456,19 @@ static struct tegra_uart_chip_data tegra186_uart_chip_data = { .fifo_mode_enable_status = true, .uart_max_port = 8, .max_dma_burst_bytes = 8, + .error_tolerance_low_range = 0, + .error_tolerance_high_range = 4, +}; + +static struct tegra_uart_chip_data tegra194_uart_chip_data = { + .tx_fifo_full_status = true, + .allow_txfifo_reset_fifo_mode = false, + .support_clk_src_div = true, + .fifo_mode_enable_status = true, + .uart_max_port = 8, + .max_dma_burst_bytes = 8, + .error_tolerance_low_range = -2, + .error_tolerance_high_range = 2, }; static const struct of_device_id tegra_uart_of_match[] = { @@ -1430,6 +1482,9 @@ static const struct of_device_id tegra_uart_of_match[] = { .compatible = "nvidia,tegra186-hsuart", .data = &tegra186_uart_chip_data, }, { + .compatible = "nvidia,tegra194-hsuart", + .data = &tegra194_uart_chip_data, + }, { }, }; MODULE_DEVICE_TABLE(of, tegra_uart_of_match); |