As per HW manual section 40.6.1, we need to perform FIFO reset + SW
reset before updating the below registers.
FCR[7:5], FCR[3:0], LCR[7][5:0], MCR[6:4], DLL[7:0], DLM[7:0] and
HCR0[6:5][3:2].
This patch adds serial_out() to struct serial8250_em_hw_info to
handle this difference between emma mobile and rz/v2m.
DLL/DLM register can be updated only by setting LCR[7]. So the
updation of LCR[7] will perform reset for DLL/DLM register changes.
Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
---
v2->v3:
* Replaced readl/writel()->serial8250_em_serial_in/out() in serial8250_rzv2m_
reg_update() to avoid duplication of offset trickery.
* Added support for HCR0 read/write in serial8250_em_{serial_in, serial_out}
* Added UART_LCR macro support in serial8250_em_serial_in() to read LCR
* Reordered serial8250_em_{serial_in, serial_out} above serial8250_rzv2m_
reg_update().
* Replaced priv->info->serial_out to info->serial_out.
v1->v2:
* Added serial_out to struct serial8250_em_hw_info
---
drivers/tty/serial/8250/8250_em.c | 67 ++++++++++++++++++++++++++++++-
1 file changed, 66 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/8250/8250_em.c b/drivers/tty/serial/8250/8250_em.c
index 69cd3b611501..a90a5cc4234a 100644
--- a/drivers/tty/serial/8250/8250_em.c
+++ b/drivers/tty/serial/8250/8250_em.c
@@ -19,10 +19,14 @@
#define UART_DLL_EM 9
#define UART_DLM_EM 10
+#define UART_HCR0 11
+
+#define UART_HCR0_SW_RESET BIT(7) /* SW Reset */
struct serial8250_em_hw_info {
unsigned int type;
upf_t flags;
+ void (*serial_out)(struct uart_port *p, int off, int value);
};
struct serial8250_em_priv {
@@ -46,6 +50,7 @@ static void serial8250_em_serial_out(struct uart_port *p, int offset, int value)
fallthrough;
case UART_DLL_EM: /* DLL @ 0x24 (+9) */
case UART_DLM_EM: /* DLM @ 0x28 (+9) */
+ case UART_HCR0: /* HCR0 @ 0x2c */
writel(value, p->membase + (offset << 2));
}
}
@@ -55,6 +60,7 @@ static unsigned int serial8250_em_serial_in(struct uart_port *p, int offset)
switch (offset) {
case UART_RX: /* RX @ 0x00 */
return readb(p->membase);
+ case UART_LCR: /* LCR @ 0x10 (+1) */
case UART_MCR: /* MCR @ 0x14 (+1) */
case UART_LSR: /* LSR @ 0x18 (+1) */
case UART_MSR: /* MSR @ 0x1c (+1) */
@@ -64,11 +70,68 @@ static unsigned int serial8250_em_serial_in(struct uart_port *p, int offset)
case UART_IIR: /* IIR @ 0x08 */
case UART_DLL_EM: /* DLL @ 0x24 (+9) */
case UART_DLM_EM: /* DLM @ 0x28 (+9) */
+ case UART_HCR0: /* HCR0 @ 0x2c */
return readl(p->membase + (offset << 2));
}
return 0;
}
+static void serial8250_rzv2m_reg_update(struct uart_port *p, int off, int value)
+{
+ unsigned int ier, fcr, lcr, mcr, hcr0;
+
+ ier = serial8250_em_serial_in(p, UART_IER);
+ lcr = serial8250_em_serial_in(p, UART_LCR);
+ mcr = serial8250_em_serial_in(p, UART_MCR);
+ hcr0 = serial8250_em_serial_in(p, UART_HCR0);
+ /*
+ * The value of UART_IIR and UART_FCR are 2, but corresponding
+ * RZ/V2M address offset are different(0x08 and 0x0c). So we need to
+ * use readl() here.
+ */
+ fcr = readl(p->membase + ((UART_FCR + 1) << 2));
+
+ serial8250_em_serial_out(p, UART_FCR, fcr | UART_FCR_CLEAR_RCVR |
+ UART_FCR_CLEAR_XMIT);
+ serial8250_em_serial_out(p, UART_HCR0, hcr0 | UART_HCR0_SW_RESET);
+ serial8250_em_serial_out(p, UART_HCR0, hcr0 & ~UART_HCR0_SW_RESET);
+
+ switch (off) {
+ case UART_FCR:
+ fcr = value;
+ break;
+ case UART_LCR:
+ lcr = value;
+ break;
+ case UART_MCR:
+ mcr = value;
+ break;
+ }
+
+ serial8250_em_serial_out(p, UART_IER, ier);
+ serial8250_em_serial_out(p, UART_FCR, fcr);
+ serial8250_em_serial_out(p, UART_MCR, mcr);
+ serial8250_em_serial_out(p, UART_LCR, lcr);
+ serial8250_em_serial_out(p, UART_HCR0, hcr0);
+}
+
+static void serial8250_em_rzv2m_serial_out(struct uart_port *p, int offset, int value)
+{
+ switch (offset) {
+ case UART_TX:
+ case UART_SCR:
+ case UART_IER:
+ case UART_DLL_EM:
+ case UART_DLM_EM:
+ serial8250_em_serial_out(p, offset, value);
+ break;
+ case UART_FCR:
+ case UART_LCR:
+ case UART_MCR:
+ serial8250_rzv2m_reg_update(p, offset, value);
+ }
+}
+
static int serial8250_em_serial_dl_read(struct uart_8250_port *up)
{
return serial_in(up, UART_DLL_EM) | serial_in(up, UART_DLM_EM) << 8;
@@ -120,7 +183,7 @@ static int serial8250_em_probe(struct platform_device *pdev)
up.port.iotype = UPIO_MEM32;
up.port.serial_in = serial8250_em_serial_in;
- up.port.serial_out = serial8250_em_serial_out;
+ up.port.serial_out = info->serial_out;
up.dl_read = serial8250_em_serial_dl_read;
up.dl_write = serial8250_em_serial_dl_write;
@@ -144,11 +207,13 @@ static int serial8250_em_remove(struct platform_device *pdev)
static const struct serial8250_em_hw_info emma_mobile_uart_hw_info = {
.type = PORT_UNKNOWN,
.flags = UPF_BOOT_AUTOCONF | UPF_FIXED_PORT | UPF_IOREMAP,
+ .serial_out = serial8250_em_serial_out,
};
static const struct serial8250_em_hw_info rzv2m_uart_hw_info = {
.type = PORT_16750,
.flags = UPF_BOOT_AUTOCONF | UPF_FIXED_PORT | UPF_IOREMAP | UPF_FIXED_TYPE,
+ .serial_out = serial8250_em_rzv2m_serial_out,
};
static const struct of_device_id serial8250_em_dt_ids[] = {
--
2.25.1
