RCC: Break out some portable functionality from stm32f1/.

Portions of rcc_clk_enable(), rcc_reset_dev(), and rcc_set_prescaler()
are portable; break these into static inline helpers in
rcc_private.h. These guts of these are portable, but the arrays of
registers etc. are not.

Also add an extern declaration for rcc_dev_table into
rcc_private.h. This lets us put rcc_dev_clk() into a newly resurrected
libmaple/rcc.c, since that's portable.

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>

4 files changed, 119 insertions, 34 deletions

diff --git a/libmaple/rcc.c b/libmaple/rcc.c
new file mode 100644
index 0000000..d6ed2d6
--- /dev/null
+++ b/libmaple/rcc.c
@@ -0,0 +1,44 @@
+/******************************************************************************
+ * The MIT License
+ *
+ * Copyright (c) 2010 Perry Hung.
+ * Copyright (c) 2011 LeafLabs, LLC.
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy,
+ * modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *****************************************************************************/
+
+/**
+ * @file libmaple/rcc.c
+ * @brief Portable RCC routines.
+ */
+
+#include <libmaple/rcc.h>
+
+#include "rcc_private.h"
+
+/**
+ * @brief Get a peripheral's clock domain
+ * @param id Clock ID of the peripheral whose clock domain to return
+ * @return Clock source for the given clock ID
+ */
+rcc_clk_domain rcc_dev_clk(rcc_clk_id id) {
+    return rcc_dev_table[id].clk_domain;
+}
diff --git a/libmaple/rcc_private.h b/libmaple/rcc_private.h
new file mode 100644
index 0000000..66eaf00
--- /dev/null
+++ b/libmaple/rcc_private.h
@@ -0,0 +1,67 @@
+/******************************************************************************
+ * The MIT License
+ *
+ * Copyright (c) 2011 LeafLabs, LLC.
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy,
+ * modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *****************************************************************************/
+
+/*
+ * RCC private header.
+ */
+
+#ifndef _LIBMAPLE_PRIVATE_RCC_H_
+#define _LIBMAPLE_PRIVATE_RCC_H_
+
+#include <libmaple/bitband.h>
+
+struct rcc_dev_info {
+    const rcc_clk_domain clk_domain;
+    const uint8 line_num;
+};
+
+extern const struct rcc_dev_info rcc_dev_table[];
+
+static inline void rcc_do_clk_enable(__io uint32** enable_regs,
+                                     rcc_clk_id id) {
+    __io uint32 *enable_reg = enable_regs[rcc_dev_clk(id)];
+    uint8 line_num = rcc_dev_table[id].line_num;
+    bb_peri_set_bit(enable_reg, line_num, 1);
+}
+
+static inline void rcc_do_reset_dev(__io uint32** reset_regs,
+                                    rcc_clk_id id) {
+    __io uint32 *reset_reg = reset_regs[rcc_dev_clk(id)];
+    uint8 line_num = rcc_dev_table[id].line_num;
+    bb_peri_set_bit(reset_reg, line_num, 1);
+    bb_peri_set_bit(reset_reg, line_num, 0);
+}
+
+static inline void rcc_do_set_prescaler(const uint32 *masks,
+                                        rcc_prescaler prescaler,
+                                        uint32 divider) {
+    uint32 cfgr = RCC_BASE->CFGR;
+    cfgr &= ~masks[prescaler];
+    cfgr |= divider;
+    RCC_BASE->CFGR = cfgr;
+}
+
+#endif
diff --git a/libmaple/rules.mk b/libmaple/rules.mk
index cbff931..3ca5b3a 100644
--- a/libmaple/rules.mk
+++ b/libmaple/rules.mk
@@ -23,6 +23,7 @@ cSRCS_$(d) := adc.c                    \
               nvic.c                   \
               pwr.c		       \
               i2c.c                    \
+              rcc.c                    \
               spi.c                    \
               syscalls.c               \
               systick.c                \
diff --git a/libmaple/stm32f1/rcc.c b/libmaple/stm32f1/rcc.c
index c40d52f..c8d24c6 100644
--- a/libmaple/stm32f1/rcc.c
+++ b/libmaple/stm32f1/rcc.c
@@ -34,10 +34,7 @@
 #include <libmaple/libmaple.h>
 #include <libmaple/bitband.h>
 
-struct rcc_dev_info {
-    const rcc_clk_domain clk_domain;
-    const uint8 line_num;
-};
+#include "rcc_private.h"
 
 #define APB1                            RCC_APB1
 #define APB2                            RCC_APB2
@@ -45,7 +42,7 @@ struct rcc_dev_info {
 
 /* Device descriptor table, maps rcc_clk_id onto bus and enable/reset
  * register bit numbers. */
-static const struct rcc_dev_info rcc_dev_table[] = {
+const struct rcc_dev_info rcc_dev_table[] = {
     [RCC_GPIOA]  = { .clk_domain = APB2, .line_num = 2 },
     [RCC_GPIOB]  = { .clk_domain = APB2, .line_num = 3 },
     [RCC_GPIOC]  = { .clk_domain = APB2, .line_num = 4 },
@@ -144,17 +141,12 @@ void rcc_clk_init(rcc_sysclk_src sysclk_src,
  * @param id Clock ID of the peripheral to turn on.
  */
 void rcc_clk_enable(rcc_clk_id id) {
-    static const __io uint32* enable_regs[] = {
+    static __io uint32* enable_regs[] = {
         [APB1] = &RCC_BASE->APB1ENR,
         [APB2] = &RCC_BASE->APB2ENR,
         [AHB] = &RCC_BASE->AHBENR,
     };
-
-    rcc_clk_domain clk_domain = rcc_dev_clk(id);
-    __io uint32* enr = (__io uint32*)enable_regs[clk_domain];
-    uint8 lnum = rcc_dev_table[id].line_num;
-
-    bb_peri_set_bit(enr, lnum, 1);
+    rcc_do_clk_enable(enable_regs, id);
 }
 
 /**
@@ -162,26 +154,11 @@ void rcc_clk_enable(rcc_clk_id id) {
  * @param id Clock ID of the peripheral to reset.
  */
 void rcc_reset_dev(rcc_clk_id id) {
-    static const __io uint32* reset_regs[] = {
+    static __io uint32* reset_regs[] = {
         [APB1] = &RCC_BASE->APB1RSTR,
         [APB2] = &RCC_BASE->APB2RSTR,
     };
-
-    rcc_clk_domain clk_domain = rcc_dev_clk(id);
-    __io void* addr = (__io void*)reset_regs[clk_domain];
-    uint8 lnum = rcc_dev_table[id].line_num;
-
-    bb_peri_set_bit(addr, lnum, 1);
-    bb_peri_set_bit(addr, lnum, 0);
-}
-
-/**
- * @brief Get a peripheral's clock domain
- * @param id Clock ID of the peripheral whose clock domain to return
- * @return Clock source for the given clock ID
- */
-rcc_clk_domain rcc_dev_clk(rcc_clk_id id) {
-    return rcc_dev_table[id].clk_domain;
+    rcc_do_reset_dev(reset_regs, id);
 }
 
 /**
@@ -197,9 +174,5 @@ void rcc_set_prescaler(rcc_prescaler prescaler, uint32 divider) {
         [RCC_PRESCALER_USB] = RCC_CFGR_USBPRE,
         [RCC_PRESCALER_ADC] = RCC_CFGR_ADCPRE,
     };
-
-    uint32 cfgr = RCC_BASE->CFGR;
-    cfgr &= ~masks[prescaler];
-    cfgr |= divider;
-    RCC_BASE->CFGR = cfgr;
+    rcc_do_set_prescaler(masks, prescaler, divider);
 }