Blackfin: gpio: add peripheral group check

Many Blackfin parts group sets of pins into a single functional unit.
This means you cannot use different pins within a group for different
peripherals.  Our resource conflict checking thus far has been limited
to individual pins, so if someone tried to grab a different pin from
the same group, it would be allowed while silently changing the other
pins in the same group.

One common example is the pin set PG12 - PG15 on BF51x parts.  They
may either be used with SPI0 (1st function), or they may be used with
PTP/PWM/AMS3 (3rd function).  Ideally, we'd like to use PG12 - PG14
for SPI0 while using PG15 with AMS3, but the hardware does not permit
this.  In the past, the software would allow the pins to be requested
this way, but ultimately things like the Blackfin SPI driver would
stop working when the hardware rerouted to a different peripheral.

Signed-off-by: steven miao <realmz6@gmail.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

arch/blackfin/kernel/bfin_gpio.c

@@ -1,7 +1,7 @@
 /*
  * GPIO Abstraction Layer
  *
- * Copyright 2006-2009 Analog Devices Inc.
+ * Copyright 2006-2010 Analog Devices Inc.
  *
  * Licensed under the GPL-2 or later
  */
@@ -215,82 +215,91 @@ static void port_setup(unsigned gpio, unsigned short usage)
 }
 
 #ifdef BF537_FAMILY
-static struct {
-	unsigned short res;
-	unsigned short offset;
-} port_mux_lut[] = {
-	{.res = P_PPI0_D13, .offset = 11},
-	{.res = P_PPI0_D14, .offset = 11},
-	{.res = P_PPI0_D15, .offset = 11},
-	{.res = P_SPORT1_TFS, .offset = 11},
-	{.res = P_SPORT1_TSCLK, .offset = 11},
-	{.res = P_SPORT1_DTPRI, .offset = 11},
-	{.res = P_PPI0_D10, .offset = 10},
-	{.res = P_PPI0_D11, .offset = 10},
-	{.res = P_PPI0_D12, .offset = 10},
-	{.res = P_SPORT1_RSCLK, .offset = 10},
-	{.res = P_SPORT1_RFS, .offset = 10},
-	{.res = P_SPORT1_DRPRI, .offset = 10},
-	{.res = P_PPI0_D8, .offset = 9},
-	{.res = P_PPI0_D9, .offset = 9},
-	{.res = P_SPORT1_DRSEC, .offset = 9},
-	{.res = P_SPORT1_DTSEC, .offset = 9},
-	{.res = P_TMR2, .offset = 8},
-	{.res = P_PPI0_FS3, .offset = 8},
-	{.res = P_TMR3, .offset = 7},
-	{.res = P_SPI0_SSEL4, .offset = 7},
-	{.res = P_TMR4, .offset = 6},
-	{.res = P_SPI0_SSEL5, .offset = 6},
-	{.res = P_TMR5, .offset = 5},
-	{.res = P_SPI0_SSEL6, .offset = 5},
-	{.res = P_UART1_RX, .offset = 4},
-	{.res = P_UART1_TX, .offset = 4},
-	{.res = P_TMR6, .offset = 4},
-	{.res = P_TMR7, .offset = 4},
-	{.res = P_UART0_RX, .offset = 3},
-	{.res = P_UART0_TX, .offset = 3},
-	{.res = P_DMAR0, .offset = 3},
-	{.res = P_DMAR1, .offset = 3},
-	{.res = P_SPORT0_DTSEC, .offset = 1},
-	{.res = P_SPORT0_DRSEC, .offset = 1},
-	{.res = P_CAN0_RX, .offset = 1},
-	{.res = P_CAN0_TX, .offset = 1},
-	{.res = P_SPI0_SSEL7, .offset = 1},
-	{.res = P_SPORT0_TFS, .offset = 0},
-	{.res = P_SPORT0_DTPRI, .offset = 0},
-	{.res = P_SPI0_SSEL2, .offset = 0},
-	{.res = P_SPI0_SSEL3, .offset = 0},
+static const s8 port_mux[] = {
+	[GPIO_PF0] = 3,
+	[GPIO_PF1] = 3,
+	[GPIO_PF2] = 4,
+	[GPIO_PF3] = 4,
+	[GPIO_PF4] = 5,
+	[GPIO_PF5] = 6,
+	[GPIO_PF6] = 7,
+	[GPIO_PF7] = 8,
+	[GPIO_PF8 ... GPIO_PF15] = -1,
+	[GPIO_PG0 ... GPIO_PG7] = -1,
+	[GPIO_PG8] = 9,
+	[GPIO_PG9] = 9,
+	[GPIO_PG10] = 10,
+	[GPIO_PG11] = 10,
+	[GPIO_PG12] = 10,
+	[GPIO_PG13] = 11,
+	[GPIO_PG14] = 11,
+	[GPIO_PG15] = 11,
+	[GPIO_PH0 ... GPIO_PH15] = -1,
+	[PORT_PJ0 ... PORT_PJ3] = -1,
+	[PORT_PJ4] = 1,
+	[PORT_PJ5] = 1,
+	[PORT_PJ6 ... PORT_PJ9] = -1,
+	[PORT_PJ10] = 0,
+	[PORT_PJ11] = 0,
 };
 
-static void portmux_setup(unsigned short per)
+static int portmux_group_check(unsigned short per)
 {
-	u16 y, offset, muxreg;
+	u16 ident = P_IDENT(per);
 	u16 function = P_FUNCT2MUX(per);
+	s8 offset = port_mux[ident];
+	u16 m, pmux, pfunc;
 
-	for (y = 0; y < ARRAY_SIZE(port_mux_lut); y++) {
-		if (port_mux_lut[y].res == per) {
-
-			/* SET PORTMUX REG */
-
-			offset = port_mux_lut[y].offset;
-			muxreg = bfin_read_PORT_MUX();
+	if (offset < 0)
+		return 0;
 
-			if (offset != 1)
-				muxreg &= ~(1 << offset);
-			else
-				muxreg &= ~(3 << 1);
+	pmux = bfin_read_PORT_MUX();
+	for (m = 0; m < ARRAY_SIZE(port_mux); ++m) {
+		if (m == ident)
+			continue;
+		if (port_mux[m] != offset)
+			continue;
+		if (!is_reserved(peri, m, 1))
+			continue;
 
-			muxreg |= (function << offset);
-			bfin_write_PORT_MUX(muxreg);
+		if (offset == 1)
+			pfunc = (pmux >> offset) & 3;
+		else
+			pfunc = (pmux >> offset) & 1;
+		if (pfunc != function) {
+			pr_err("pin group conflict! request pin %d func %d conflict with pin %d func %d\n",
+				ident, function, m, pfunc);
+			return -EINVAL;
 		}
 	}
+
+	return 0;
+}
+
+static void portmux_setup(unsigned short per)
+{
+	u16 ident = P_IDENT(per);
+	u16 function = P_FUNCT2MUX(per);
+	s8 offset = port_mux[ident];
+	u16 pmux;
+
+	if (offset == -1)
+		return;
+
+	pmux = bfin_read_PORT_MUX();
+	if (offset != 1)
+		pmux &= ~(1 << offset);
+	else
+		pmux &= ~(3 << 1);
+	pmux |= (function << offset);
+	bfin_write_PORT_MUX(pmux);
 }
 #elif defined(CONFIG_BF54x)
 inline void portmux_setup(unsigned short per)
 {
-	u32 pmux;
 	u16 ident = P_IDENT(per);
 	u16 function = P_FUNCT2MUX(per);
+	u32 pmux;
 
 	pmux = gpio_array[gpio_bank(ident)]->port_mux;
 
@@ -302,20 +311,54 @@ inline void portmux_setup(unsigned short per)
 
 inline u16 get_portmux(unsigned short per)
 {
-	u32 pmux;
 	u16 ident = P_IDENT(per);
-
-	pmux = gpio_array[gpio_bank(ident)]->port_mux;
-
+	u32 pmux = gpio_array[gpio_bank(ident)]->port_mux;
 	return (pmux >> (2 * gpio_sub_n(ident)) & 0x3);
 }
+static int portmux_group_check(unsigned short per)
+{
+	return 0;
+}
 #elif defined(CONFIG_BF52x) || defined(CONFIG_BF51x)
+static int portmux_group_check(unsigned short per)
+{
+	u16 ident = P_IDENT(per);
+	u16 function = P_FUNCT2MUX(per);
+	u8 offset = pmux_offset[gpio_bank(ident)][gpio_sub_n(ident)];
+	u16 pin, gpiopin, pfunc;
+
+	for (pin = 0; pin < GPIO_BANKSIZE; ++pin) {
+		if (offset != pmux_offset[gpio_bank(ident)][pin])
+			continue;
+
+		gpiopin = gpio_bank(ident) * GPIO_BANKSIZE + pin;
+		if (gpiopin == ident)
+			continue;
+		if (!is_reserved(peri, gpiopin, 1))
+			continue;
+
+		pfunc = *port_mux[gpio_bank(ident)];
+		pfunc = (pfunc >> offset) & 3;
+		if (pfunc != function) {
+			pr_err("pin group conflict! request pin %d func %d conflict with pin %d func %d\n",
+				ident, function, gpiopin, pfunc);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
 inline void portmux_setup(unsigned short per)
 {
-	u16 pmux, ident = P_IDENT(per), function = P_FUNCT2MUX(per);
+	u16 ident = P_IDENT(per);
+	u16 function = P_FUNCT2MUX(per);
 	u8 offset = pmux_offset[gpio_bank(ident)][gpio_sub_n(ident)];
+	u16 pmux;
 
 	pmux = *port_mux[gpio_bank(ident)];
+	if  (((pmux >> offset) & 3) == function)
+		return;
 	pmux &= ~(3 << offset);
 	pmux |= (function & 3) << offset;
 	*port_mux[gpio_bank(ident)] = pmux;
@@ -323,6 +366,10 @@ inline void portmux_setup(unsigned short per)
 }
 #else
 # define portmux_setup(...)  do { } while (0)
+static int portmux_group_check(unsigned short per)
+{
+	return 0;
+}
 #endif
 
 #ifndef CONFIG_BF54x
@@ -735,6 +782,10 @@ int peripheral_request(unsigned short per, const char *label)
 		}
 	}
 
+	if (unlikely(portmux_group_check(per))) {
+		hard_local_irq_restore(flags);
+		return -EBUSY;
+	}
  anyway:
 	reserve(peri, ident);