[PATCH V6] serial: msm_geni_serial_console : Add Earlycon support
From: Akash Asthana
Date: Mon Jun 22 2020 - 06:09:04 EST
From: Mukesh Kumar Savaliya <msavaliy@xxxxxxxxxxxxxx>
This change enables earlyconsole support as static driver for geni
based UART. Kernel space UART console driver will be generic for
console and other usecases of UART.
Signed-off-by: Mukesh Kumar Savaliya <msavaliy@xxxxxxxxxxxxxx>
Signed-off-by: Akash Asthana <akashast@xxxxxxxxxxxxxx>
---
Changes In V2:
- Fixed Makefile Typo issue.
Changes In V3:
- Removed mb() calls as *_relaxed() should take care.
Changes In V4:
- Minor change: space between offset and base addition.
Changes In V5:
- Removed unlikely() macro.
- root_freq() array taken as static.
- Removed extra readback of the register having no meaning.
Changes in V6:
- Drop SERIAL_MSM_GENI_HALF_SAMPLING config and support only
QUP HW ver > 2.5. As of now no device with QUP ver < 2.5 is using this
code for earlycon so it won't break them. I will post separate patch to
resolve this limitation.
Sending patch on behalf of Mukesh Savaliya.
drivers/tty/serial/Kconfig | 7 +
drivers/tty/serial/Makefile | 1 +
drivers/tty/serial/msm_geni_serial_console.c | 480 +++++++++++++++++++++++++++
3 files changed, 488 insertions(+)
create mode 100644 drivers/tty/serial/msm_geni_serial_console.c
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 780908d..47caaa6 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -956,6 +956,13 @@ config SERIAL_MSM_CONSOLE
select SERIAL_CORE_CONSOLE
select SERIAL_EARLYCON
+config SERIAL_MSM_GENI_EARLY_CONSOLE
+ bool "MSM on-chip GENI HW based early console support"
+ select SERIAL_MSM_GENI_HALF_SAMPLING
+ help
+ Serial early console driver for Qualcomm Technologies Inc's GENI
+ based QUP hardware.
+
config SERIAL_QCOM_GENI
tristate "QCOM on-chip GENI based serial port support"
depends on ARCH_QCOM || COMPILE_TEST
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index d056ee6..7b6422e 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -55,6 +55,7 @@ obj-$(CONFIG_SERIAL_VR41XX) += vr41xx_siu.o
obj-$(CONFIG_SERIAL_ATMEL) += atmel_serial.o
obj-$(CONFIG_SERIAL_UARTLITE) += uartlite.o
obj-$(CONFIG_SERIAL_MSM) += msm_serial.o
+obj-$(CONFIG_SERIAL_MSM_GENI_EARLY_CONSOLE) += msm_geni_serial_console.o
obj-$(CONFIG_SERIAL_QCOM_GENI) += qcom_geni_serial.o
obj-$(CONFIG_SERIAL_OMAP) += omap-serial.o
obj-$(CONFIG_SERIAL_ALTERA_UART) += altera_uart.o
diff --git a/drivers/tty/serial/msm_geni_serial_console.c b/drivers/tty/serial/msm_geni_serial_console.c
new file mode 100644
index 0000000..80a7231
--- /dev/null
+++ b/drivers/tty/serial/msm_geni_serial_console.c
@@ -0,0 +1,480 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2020, The Linux Foundation. All rights reserved.
+ */
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/serial_core.h>
+
+#define SE_UART_TX_TRANS_CFG (0x25C)
+#define SE_UART_TX_WORD_LEN (0x268)
+#define SE_UART_TX_STOP_BIT_LEN (0x26C)
+#define SE_UART_TX_TRANS_LEN (0x270)
+#define SE_UART_TX_PARITY_CFG (0x2A4)
+/* SE_UART_TRANS_CFG */
+#define UART_CTS_MASK (BIT(1))
+/* UART M_CMD OP codes */
+#define UART_START_TX (0x1)
+
+#define UART_OVERSAMPLING (32)
+#define DEF_FIFO_DEPTH_WORDS (16)
+#define DEF_TX_WM (2)
+#define DEF_FIFO_WIDTH_BITS (32)
+
+#define GENI_FORCE_DEFAULT_REG (0x20)
+#define GENI_OUTPUT_CTRL (0x24)
+#define GENI_CGC_CTRL (0x28)
+#define GENI_SER_M_CLK_CFG (0x48)
+#define GENI_FW_REVISION_RO (0x68)
+
+#define SE_GENI_TX_PACKING_CFG0 (0x260)
+#define SE_GENI_TX_PACKING_CFG1 (0x264)
+#define SE_GENI_M_CMD0 (0x600)
+#define SE_GENI_M_CMD_CTRL_REG (0x604)
+#define SE_GENI_M_IRQ_STATUS (0x610)
+#define SE_GENI_M_IRQ_EN (0x614)
+#define SE_GENI_M_IRQ_CLEAR (0x618)
+#define SE_GENI_TX_FIFOn (0x700)
+#define SE_GENI_TX_WATERMARK_REG (0x80C)
+
+#define SE_IRQ_EN (0xE1C)
+#define SE_HW_PARAM_0 (0xE24)
+#define SE_HW_PARAM_1 (0xE28)
+
+/* GENI_OUTPUT_CTRL fields */
+#define DEFAULT_IO_OUTPUT_CTRL_MSK (GENMASK(6, 0))
+
+/* GENI_FORCE_DEFAULT_REG fields */
+#define FORCE_DEFAULT (BIT(0))
+
+/* GENI_CGC_CTRL fields */
+#define CFG_AHB_CLK_CGC_ON (BIT(0))
+#define CFG_AHB_WR_ACLK_CGC_ON (BIT(1))
+#define DATA_AHB_CLK_CGC_ON (BIT(2))
+#define SCLK_CGC_ON (BIT(3))
+#define TX_CLK_CGC_ON (BIT(4))
+#define RX_CLK_CGC_ON (BIT(5))
+#define EXT_CLK_CGC_ON (BIT(6))
+#define PROG_RAM_HCLK_OFF (BIT(8))
+#define PROG_RAM_SCLK_OFF (BIT(9))
+#define DEFAULT_CGC_EN (GENMASK(6, 0))
+
+/* GENI_STATUS fields */
+#define M_GENI_CMD_ACTIVE (BIT(0))
+
+/* GENI_SER_M_CLK_CFG/GENI_SER_S_CLK_CFG */
+#define SER_CLK_EN (BIT(0))
+#define CLK_DIV_MSK (GENMASK(15, 4))
+#define CLK_DIV_SHFT (4)
+
+/* CLK_CTRL_RO fields */
+
+/* FIFO_IF_DISABLE_RO fields */
+#define FIFO_IF_DISABLE (BIT(0))
+
+/* FW_REVISION_RO fields */
+#define FW_REV_PROTOCOL_MSK (GENMASK(15, 8))
+#define FW_REV_PROTOCOL_SHFT (8)
+#define FW_REV_VERSION_MSK (GENMASK(7, 0))
+
+/* GENI_CLK_SEL fields */
+#define CLK_SEL_MSK (GENMASK(2, 0))
+
+/* SE_GENI_DMA_MODE_EN */
+#define GENI_DMA_MODE_EN (BIT(0))
+
+/* GENI_M_CMD0 fields */
+#define M_OPCODE_MSK (GENMASK(31, 27))
+#define M_OPCODE_SHFT (27)
+#define M_PARAMS_MSK (GENMASK(26, 0))
+
+/* GENI_M_CMD_CTRL_REG */
+#define M_GENI_CMD_CANCEL BIT(2)
+#define M_GENI_CMD_ABORT BIT(1)
+#define M_GENI_DISABLE BIT(0)
+
+/* GENI_M_IRQ_EN fields */
+#define M_CMD_DONE_EN (BIT(0))
+#define M_CMD_OVERRUN_EN (BIT(1))
+#define M_ILLEGAL_CMD_EN (BIT(2))
+#define M_CMD_FAILURE_EN (BIT(3))
+#define M_CMD_CANCEL_EN (BIT(4))
+#define M_CMD_ABORT_EN (BIT(5))
+#define M_TIMESTAMP_EN (BIT(6))
+#define M_GP_SYNC_IRQ_0_EN (BIT(8))
+#define M_IO_DATA_DEASSERT_EN (BIT(22))
+#define M_IO_DATA_ASSERT_EN (BIT(23))
+#define M_TX_FIFO_RD_ERR_EN (BIT(28))
+#define M_TX_FIFO_WR_ERR_EN (BIT(29))
+#define M_TX_FIFO_WATERMARK_EN (BIT(30))
+#define M_SEC_IRQ_EN (BIT(31))
+#define M_COMMON_GENI_M_IRQ_EN (GENMASK(6, 1) | \
+ M_IO_DATA_DEASSERT_EN | \
+ M_IO_DATA_ASSERT_EN | M_TX_FIFO_RD_ERR_EN | \
+ M_TX_FIFO_WR_ERR_EN)
+
+
+/* GENI_TX_FIFO_STATUS fields */
+#define TX_FIFO_WC (GENMASK(27, 0))
+
+/* SE_IRQ_EN fields */
+#define GENI_M_IRQ_EN (BIT(2))
+
+#define UART_PROTOCOL 2
+#define GET_DEV_PORT(uport) \
+ container_of(uport, struct msm_geni_serial_earlycon_port, uport)
+
+
+static int get_se_proto_earlycon(void __iomem *base)
+{
+ int proto;
+
+ proto = ((readl_relaxed(base + GENI_FW_REVISION_RO)
+ & FW_REV_PROTOCOL_MSK) >> FW_REV_PROTOCOL_SHFT);
+ return proto;
+}
+
+static void se_get_packing_config_earlycon(int bpw, int pack_words,
+ bool msb_to_lsb, unsigned long *cfg0, unsigned long *cfg1)
+{
+ u32 cfg[4] = {0};
+ int len, i;
+ int temp_bpw = bpw;
+ int idx_start = (msb_to_lsb ? (bpw - 1) : 0);
+ int idx_delta = (msb_to_lsb ? -BITS_PER_BYTE : BITS_PER_BYTE);
+ int ceil_bpw = ((bpw & (BITS_PER_BYTE - 1)) ?
+ ((bpw & ~(BITS_PER_BYTE - 1)) + BITS_PER_BYTE) : bpw);
+ int iter = (ceil_bpw * pack_words) >> 3;
+ int idx = idx_start;
+
+ if (iter <= 0 || iter > 4) {
+ *cfg0 = 0;
+ *cfg1 = 0;
+ return;
+ }
+
+ for (i = 0; i < iter; i++) {
+ len = (temp_bpw < BITS_PER_BYTE) ?
+ (temp_bpw - 1) : BITS_PER_BYTE - 1;
+ cfg[i] = ((idx << 5) | (msb_to_lsb << 4) | (len << 1));
+ idx = ((temp_bpw - BITS_PER_BYTE) <= 0) ?
+ ((i + 1) * BITS_PER_BYTE) + idx_start :
+ idx + idx_delta;
+ temp_bpw = ((temp_bpw - BITS_PER_BYTE) <= 0) ?
+ bpw : (temp_bpw - BITS_PER_BYTE);
+ }
+ cfg[iter - 1] |= 1;
+ *cfg0 = cfg[0] | (cfg[1] << 10);
+ *cfg1 = cfg[2] | (cfg[3] << 10);
+}
+
+static void se_geni_irq_en_earlycon(void __iomem *base)
+{
+ unsigned int common_geni_m_irq_en;
+
+ common_geni_m_irq_en = readl_relaxed(base + SE_GENI_M_IRQ_EN);
+ common_geni_m_irq_en |= M_COMMON_GENI_M_IRQ_EN;
+ writel_relaxed(common_geni_m_irq_en, base + SE_GENI_M_IRQ_EN);
+}
+
+static void se_io_set_mode_earlycon(void __iomem *base)
+{
+ unsigned int io_mode;
+
+ io_mode = readl_relaxed(base + SE_IRQ_EN);
+ io_mode |= (GENI_M_IRQ_EN);
+ writel_relaxed(io_mode, base + SE_IRQ_EN);
+}
+
+static void se_io_init_earlycon(void __iomem *base)
+{
+ unsigned int io_op_ctrl;
+ unsigned int geni_cgc_ctrl;
+
+ geni_cgc_ctrl = readl_relaxed(base + GENI_CGC_CTRL);
+ geni_cgc_ctrl |= DEFAULT_CGC_EN;
+ io_op_ctrl = DEFAULT_IO_OUTPUT_CTRL_MSK;
+ writel_relaxed(geni_cgc_ctrl, base + GENI_CGC_CTRL);
+
+ writel_relaxed(io_op_ctrl, base + GENI_OUTPUT_CTRL);
+ writel_relaxed(FORCE_DEFAULT, base + GENI_FORCE_DEFAULT_REG);
+}
+
+static void geni_se_select_fifo_mode_earlycon(void __iomem *base)
+{
+ unsigned int common_geni_m_irq_en;
+
+ writel_relaxed(0xFFFFFFFF, base + SE_GENI_M_IRQ_CLEAR);
+ writel_relaxed(0xFFFFFFFF, base + SE_IRQ_EN);
+
+ common_geni_m_irq_en = readl_relaxed(base + SE_GENI_M_IRQ_EN);
+ writel_relaxed(common_geni_m_irq_en, base + SE_GENI_M_IRQ_EN);
+}
+
+struct msm_geni_serial_earlycon_port {
+ struct uart_port uport;
+ unsigned int tx_fifo_depth;
+ unsigned int tx_fifo_width;
+ unsigned int tx_wm;
+ unsigned int xmit_size;
+ unsigned int cur_baud;
+};
+
+static int get_clk_cfg(unsigned long clk_freq, unsigned long *ser_clk)
+{
+ static unsigned long root_freq[] = {7372800, 14745600, 19200000,
+ 29491200, 32000000, 48000000, 64000000, 80000000, 96000000,
+ 100000000, 102400000, 112000000, 120000000, 128000000};
+ int i;
+ int match = -1;
+
+ for (i = 0; i < ARRAY_SIZE(root_freq); i++) {
+ if (clk_freq > root_freq[i])
+ continue;
+
+ if (!(root_freq[i] % clk_freq)) {
+ match = i;
+ break;
+ }
+ }
+ if (match != -1)
+ *ser_clk = root_freq[match];
+
+ return match;
+}
+
+
+static int get_clk_div_rate(unsigned int baud, unsigned long *desired_clk_rate)
+{
+ unsigned long ser_clk;
+ int dfs_index;
+ int clk_div = 0;
+
+ *desired_clk_rate = baud * UART_OVERSAMPLING;
+ dfs_index = get_clk_cfg(*desired_clk_rate, &ser_clk);
+ if (dfs_index < 0) {
+ clk_div = -EINVAL;
+ goto exit_get_clk_div_rate;
+ }
+
+ clk_div = ser_clk / *desired_clk_rate;
+ *desired_clk_rate = ser_clk;
+exit_get_clk_div_rate:
+ return clk_div;
+}
+
+
+static void msm_geni_serial_wr_char(struct uart_port *uport, int ch)
+{
+ writel_relaxed(ch, uport->membase + SE_GENI_TX_FIFOn);
+}
+
+static int msm_geni_serial_poll_bit(struct uart_port *uport,
+ int offset, int bit_field, bool set)
+{
+ int iter = 0;
+ bool met = false, cond = false;
+ unsigned int reg, baud = 115200, total_iter = 1000;
+ unsigned int fifo_bits = DEF_FIFO_DEPTH_WORDS * DEF_FIFO_WIDTH_BITS;
+ struct msm_geni_serial_earlycon_port *port = NULL;
+
+ if (uport->private_data && !uart_console(uport)) {
+ port = GET_DEV_PORT(uport);
+ baud = (port->cur_baud ? port->cur_baud : 115200);
+ fifo_bits = port->tx_fifo_depth * port->tx_fifo_width;
+ /*
+ * Total polling iterations based on FIFO worth of bytes to be
+ * sent at current baud. Add a little fluff to the wait.
+ */
+ total_iter = ((fifo_bits * USEC_PER_SEC) / baud) / 10;
+ total_iter += 50;
+ }
+
+ while (iter < total_iter) {
+ reg = readl_relaxed(uport->membase + offset);
+ cond = reg & bit_field;
+ if (cond == set) {
+ met = true;
+ break;
+ }
+ udelay(10);
+ iter++;
+ }
+ return met;
+}
+
+static void msm_geni_serial_poll_cancel_tx(struct uart_port *uport)
+{
+ int done = 0;
+ unsigned int irq_clear = M_CMD_DONE_EN;
+
+ done = msm_geni_serial_poll_bit(uport, SE_GENI_M_IRQ_STATUS,
+ M_CMD_DONE_EN, true);
+ if (!done) {
+ writel_relaxed(M_GENI_CMD_ABORT,
+ uport->membase + SE_GENI_M_CMD_CTRL_REG);
+ irq_clear |= M_CMD_ABORT_EN;
+ msm_geni_serial_poll_bit(uport, SE_GENI_M_IRQ_STATUS,
+ M_CMD_ABORT_EN, true);
+ }
+ writel_relaxed(irq_clear, uport->membase + SE_GENI_M_IRQ_CLEAR);
+}
+
+static void msm_geni_serial_setup_tx(struct uart_port *uport,
+ unsigned int xmit_size)
+{
+ u32 m_cmd = 0;
+
+ writel_relaxed(xmit_size, uport->membase + SE_UART_TX_TRANS_LEN);
+ m_cmd |= (UART_START_TX << M_OPCODE_SHFT);
+ writel_relaxed(m_cmd, uport->membase + SE_GENI_M_CMD0);
+}
+
+
+static void
+__msm_geni_serial_console_write(struct uart_port *uport, const char *s,
+ unsigned int count)
+{
+ int new_line = 0;
+ int i;
+ int bytes_to_send = count;
+ int fifo_depth = DEF_FIFO_DEPTH_WORDS;
+ int tx_wm = DEF_TX_WM;
+
+ for (i = 0; i < count; i++) {
+ if (s[i] == '\n')
+ new_line++;
+ }
+
+ bytes_to_send += new_line;
+ writel_relaxed(tx_wm, uport->membase + SE_GENI_TX_WATERMARK_REG);
+ msm_geni_serial_setup_tx(uport, bytes_to_send);
+ i = 0;
+ while (i < count) {
+ u32 chars_to_write = 0;
+ u32 avail_fifo_bytes = (fifo_depth - tx_wm);
+ /*
+ * If the WM bit never set, then the Tx state machine is not
+ * in a valid state, so break, cancel/abort any existing
+ * command. Unfortunately the current data being written is
+ * lost.
+ */
+ while (!msm_geni_serial_poll_bit(uport, SE_GENI_M_IRQ_STATUS,
+ M_TX_FIFO_WATERMARK_EN, true))
+ break;
+ chars_to_write = min((unsigned int)(count - i),
+ avail_fifo_bytes);
+ if ((chars_to_write << 1) > avail_fifo_bytes)
+ chars_to_write = (avail_fifo_bytes >> 1);
+ uart_console_write(uport, (s + i), chars_to_write,
+ msm_geni_serial_wr_char);
+ writel_relaxed(M_TX_FIFO_WATERMARK_EN,
+ uport->membase + SE_GENI_M_IRQ_CLEAR);
+ i += chars_to_write;
+ }
+ msm_geni_serial_poll_cancel_tx(uport);
+}
+
+
+static void
+msm_geni_serial_early_console_write(struct console *con, const char *s,
+ unsigned int n)
+{
+ struct earlycon_device *dev = con->data;
+
+ __msm_geni_serial_console_write(&dev->port, s, n);
+}
+
+static int __init
+msm_geni_serial_earlycon_setup(struct earlycon_device *dev,
+ const char *opt)
+{
+ struct uart_port *uport = &dev->port;
+ int ret = 0;
+ u32 tx_trans_cfg = 0;
+ u32 tx_parity_cfg = 0;
+ u32 rx_trans_cfg = 0;
+ u32 rx_parity_cfg = 0;
+ u32 stop_bit = 0;
+ u32 rx_stale = 0;
+ u32 bits_per_char = 0;
+ u32 s_clk_cfg = 0;
+ u32 baud = 115200;
+ int clk_div;
+ unsigned long clk_rate;
+ unsigned long cfg0, cfg1;
+
+ if (!uport->membase) {
+ ret = -ENOMEM;
+ goto exit_geni_serial_earlyconsetup;
+ }
+
+ if (get_se_proto_earlycon(uport->membase) != UART_PROTOCOL) {
+ ret = -ENXIO;
+ goto exit_geni_serial_earlyconsetup;
+ }
+
+ /*
+ * Ignore Flow control.
+ * Disable Tx Parity.
+ * Don't check Parity during Rx.
+ * Disable Rx Parity.
+ * n = 8.
+ * Stop bit = 0.
+ * Stale timeout in bit-time (3 chars worth).
+ */
+ tx_trans_cfg |= UART_CTS_MASK;
+ tx_parity_cfg = 0;
+ rx_trans_cfg = 0;
+ rx_parity_cfg = 0;
+ bits_per_char = 0x8;
+ stop_bit = 0;
+ rx_stale = 0x18;
+ clk_div = get_clk_div_rate(baud, &clk_rate);
+ if (clk_div <= 0) {
+ ret = -EINVAL;
+ goto exit_geni_serial_earlyconsetup;
+ }
+ /* QUP HW ver > 2.5 needs 16 clock pulses to sample
+ * 1 bit of data, instead of 32 clock pulses in older
+ * QUP HW.
+ * For now, support only QUP HW ver > 2.5. So reduce the
+ * clk frequency to half by doubling the divider value.
+ */
+ clk_div *= 2;
+
+ s_clk_cfg |= SER_CLK_EN;
+ s_clk_cfg |= (clk_div << CLK_DIV_SHFT);
+
+ /*
+ * Make an unconditional cancel on the main sequencer to reset
+ * it else we could end up in data loss scenarios.
+ */
+ writel_relaxed(0x21, uport->membase + GENI_SER_M_CLK_CFG);
+ readl_relaxed(uport->membase + GENI_SER_M_CLK_CFG);
+
+ msm_geni_serial_poll_cancel_tx(uport);
+
+ se_get_packing_config_earlycon(8, 1, false, &cfg0, &cfg1);
+
+ se_io_init_earlycon(uport->membase);
+ se_io_set_mode_earlycon(uport->membase);
+ se_geni_irq_en_earlycon(uport->membase);
+
+ geni_se_select_fifo_mode_earlycon(uport->membase);
+ writel_relaxed(cfg0, uport->membase + SE_GENI_TX_PACKING_CFG0);
+ writel_relaxed(cfg1, uport->membase + SE_GENI_TX_PACKING_CFG1);
+ writel_relaxed(tx_trans_cfg, uport->membase + SE_UART_TX_TRANS_CFG);
+ writel_relaxed(tx_parity_cfg, uport->membase + SE_UART_TX_PARITY_CFG);
+ writel_relaxed(bits_per_char, uport->membase + SE_UART_TX_WORD_LEN);
+ writel_relaxed(stop_bit, uport->membase + SE_UART_TX_STOP_BIT_LEN);
+ writel_relaxed(s_clk_cfg, uport->membase + GENI_SER_M_CLK_CFG);
+
+ dev->con->write = msm_geni_serial_early_console_write;
+ dev->con->setup = NULL;
+exit_geni_serial_earlyconsetup:
+ return ret;
+}
+OF_EARLYCON_DECLARE(msm_geni_serial, "qcom,msm-geni-console",
+ msm_geni_serial_earlycon_setup);
--
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