Large reorganization.

What was in core/ is now moved to arch/stm34l4xxx/peripherals.  This new
directory is *supposed to* to contain raw header files defining just the
pertinent register structures for the various peripherals.  Peripheral
management belongs somewhere in the new `kern/..` directories. This is
not completely the case at the moment, so more refactoring needs to be
done.

What was sitting in the root has now been moved into the kern/
directory. The kern/ directory is to contain everything else
other than raw device register definitions. The root of the kern/
tree is reserved for standard library-esque headers.

The kern/<peripheral> directory contains management systems for that
peripheral. (At the moment DMA is the only peripheral with a decent
management system.) Preferably these peripheral systems should only
include their correlating header in arch/stm34l4xxx/peripherals, and
use other management systems for handling other peripherals rather
than manipulating their raw registers directly. (Though this ideal
will require much more critical mass of management systems.)

7 files changed, 402 insertions, 0 deletions

diff --git a/02-usart/include/kern/common.h b/02-usart/include/kern/common.h
new file mode 100644
index 0000000..653279e
--- /dev/null
+++ b/02-usart/include/kern/common.h
@@ -0,0 +1,50 @@
+#ifndef COMMON__H
+#define COMMON__H
+
+#include <stdint.h>
+#include <stddef.h>
+#include <assert.h>
+
+#define WEAK __attribute__((weak))
+#define NORETURN __attribute__((noreturn))
+
+#ifndef static_assert
+#define static_assert(a, b)
+#endif
+
+/* Define __IO to be volatile if it's not already. */
+#ifndef __IO
+#define __IO volatile
+#endif
+
+#define CTZ(n) __builtin_ctz(n)
+
+#define bool int
+#ifndef __cplusplus
+#define true 1
+#define false 0
+#endif
+
+#define PACKED __attribute__((packed))
+#define BIT(n) (1 << (n))
+
+#define RESERVED_CONCAT_IMPL(x, y) x ## y
+#define RESERVED_MACRO_CONCAT(x, y) RESERVED_CONCAT_IMPL(x, y)
+#define RESERVED(n) \
+  bits_t RESERVED_MACRO_CONCAT(_r, __COUNTER__) :n
+  
+#define RESERVE(type) \
+  __IO type RESERVED_MACRO_CONCAT(_r, __COUNTER__)
+
+#define ptr2reg(ptr) \
+  ((uint32_t) (ptrdiff_t) (ptr))
+
+typedef __IO uint32_t bits_t;
+
+#define regset(reg, mask, val) \
+  ((reg) = ((reg) & ~mask) | (val << CTZ(mask)))
+
+#define regget(reg, mask) \
+  (((reg) & mask) >> (CTZ(mask)))
+
+#endif /* COMMON_H */
diff --git a/02-usart/include/kern/delay.h b/02-usart/include/kern/delay.h
new file mode 100644
index 0000000..65a26d6
--- /dev/null
+++ b/02-usart/include/kern/delay.h
@@ -0,0 +1,12 @@
+#ifndef H__DELAY__
+#define H__DELAY__
+
+#include <stdint.h>
+
+/*
+ * Loops and count-downs the delay, the time this takes depends on the speed
+ * of the clock.
+ */
+void delay(uint32_t delay);
+
+#endif /* H__DELAY__ */
diff --git a/02-usart/include/kern/dma/dma_manager.h b/02-usart/include/kern/dma/dma_manager.h
new file mode 100644
index 0000000..0d17bd5
--- /dev/null
+++ b/02-usart/include/kern/dma/dma_manager.h
@@ -0,0 +1,279 @@
+#ifndef PERI_DMA_H_
+#define PERI_DMA_H_
+
+#include "kern/common.h"
+#include "arch/stm32l4xxx/peripherals/dma.h" /* Access to the DMA registers. */
+#include "arch/stm32l4xxx/peripherals/irq.h"
+
+#define DMA_ERROR_CHANNEL_IN_USE 1
+
+#define CAT2(x, y) x ## y
+#define CAT1(v, c) CAT2(v, c)
+#define DMA_RESERVED(dma) CAT1(dma ## _PERIPH_RESERVED, __COUNTER__)
+
+#define ALTERNATE0 0x0000
+#define ALTERNATE1 0x0100
+#define ALTERNATE2 0x0200
+#define ALTERNATE3 0x0300
+
+#define DMA_N_CHANNELS 7
+typedef enum {
+  DMA1_PERIPH_ADC1        = 0,
+  DMA1_PERIPH_ADC2        = 1,
+  DMA1_PERIPH_ADC3        = 2,
+  DMA1_PERIPH_DFSDM1_FLT0 = 3,
+  DMA1_PERIPH_DFSDM1_FLT1 = 4,
+  DMA1_PERIPH_DFSDM1_FLT2 = 5,
+  DMA1_PERIPH_DFSDM1_FLT3 = 6,
+
+  DMA_RESERVED(DMA1)  = 7,
+  DMA1_PERIPH_SPI1_RX = 8,
+  DMA1_PERIPH_SPI1_TX = 9,
+  DMA1_PERIPH_SPI2_RX = 10,
+  DMA1_PERIPH_SPI2_TX = 11,
+  DMA1_PERIPH_SAI2_A  = 12,
+  DMA1_PERIPH_SAI2_B  = 13,
+
+  DMA_RESERVED(DMA1)    = 14,
+  DMA1_PERIPH_USART3_TX = 15,
+  DMA1_PERIPH_USART3_RX = 16,
+  DMA1_PERIPH_USART1_TX = 17,
+  DMA1_PERIPH_USART1_RX = 18,
+  DMA1_PERIPH_USART2_RX = 19,
+  DMA1_PERIPH_USART2_TX = 20,
+
+  DMA_RESERVED(DMA1)  = 21,
+  DMA1_PERIPH_I2C3_TX = 22,
+  DMA1_PERIPH_I2C3_RX = 23,
+  DMA1_PERIPH_I2C2_TX = 24,
+  DMA1_PERIPH_I2C2_RX = 25,
+  DMA1_PERIPH_I2C1_TX = 26,
+  DMA1_PERIPH_I2C1_RX = 27,
+
+  DMA1_PERIPH_TIM2_CH3    = 28,
+  DMA1_PERIPH_TIM2_UP     = 29,
+  DMA1_PERIPH_TIM16_CH1_1 = 30 | ALTERNATE0,
+  DMA1_PERIPH_TIM16_UP_1  = 30 | ALTERNATE1, /* Same as TIM16_CH1. */
+  DMA_RESERVED(DMA1)      = 31,
+  DMA1_PERIPH_TIM2_CH1    = 32,
+  DMA1_PERIPH_TIM16_CH1_2 = 33,
+  DMA1_PERIPH_TIM16_UP_2  = 33 | ALTERNATE1, /* Same as TIM16_CH1. */
+  DMA1_PERIPH_TIM2_CH2    = 34,
+  DMA1_PERIPH_TIM2_CH4    = 34 | ALTERNATE1, /* Same as TIM2_CH2. */
+
+
+  DMA1_PERIPH_TIM17_CH1_1  = 35,
+  DMA1_PERIPH_TIM17_UP_1   = 35 | ALTERNATE1, /* Same as TIM17_CH1 */
+  DMA1_PERIPH_TIM3_CH3     = 36,
+  DMA1_PERIPH_TIM3_CH4     = 37,
+  DMA1_PERIPH_TIM3_UP      = 37 | ALTERNATE1, /* Same as TIM3_CH4 */
+  DMA1_PERIPH_TIM7_UP      = 38,
+  DMA1_PERIPH_DAC_CH2      = 38 | ALTERNATE1, /* Same as TIM7_UP */
+  DMA1_PERIPH_QUADSPI      = 39,
+  DMA1_PERIPH_TIM3_CH1     = 40,
+  DMA1_PERIPH_TIM3_TRIG    = 40 | ALTERNATE1, /* Same as TIM3_CH1 */
+  DMA1_PERIPH_TIM17_CH1_2  = 41,
+  DMA1_PERIPH_TIM17_UP_2   = 41 | ALTERNATE1, /* Same as TIM17_CH1 */
+
+  DMA1_PERIPH_TIM4_CH1 = 42,
+  DMA_RESERVED(DMA1)   = 43,
+  DMA1_PERIPH_TIM6_UP  = 44,
+  DMA1_PERIPH_DAC_CH1  = 44 | ALTERNATE1, /* Same as TIM6_UP */
+  DMA1_PERIPH_TIM4_CH2 = 45,
+  DMA1_PERIPH_TIM4_CH3 = 46,
+  DMA_RESERVED(DMA1)   = 47,
+  DMA1_PERIPH_TIM4_UP  = 48,
+
+  DMA_DMA1_PERIHP_RESERVED5    = 49,
+  DMA1_PERIPH_TIM1_CH1   = 50,
+  DMA1_PERIPH_TIM1_CH2   = 51,
+  DMA1_PERIPH_TIM1_CH4   = 52,
+  DMA1_PERIPH_TIM1_TRIG  = 52 | ALTERNATE1, /* Same as TIM1_TRIG */
+  DMA1_PERIPH_TIM1_COM   = 52 | ALTERNATE2, /* Same as TIM1_TRIG */
+  DMA1_PERIPH_TIM15_CH1  = 53,
+  DMA1_PERIPH_TIM15_UP   = 53 | ALTERNATE1, /* Same as TIM15_CH1 */
+  DMA1_PERIPH_TIM15_TRIG = 53 | ALTERNATE2, /* Same as TIM15_CH1 */
+  DMA1_PERIPH_TIM15_COM  = 53 | ALTERNATE3, /* Same as TIM15_CH1 */
+  DMA1_PERIPH_TIM1_UP    = 54,
+  DMA1_PERIPH_TIM1_CH3   = 55,
+
+  DMA2_DMA1_SWITCH__     = 56,
+
+  DMA2_PERIPH_I2C4_RX    = 56,
+  DMA2_PERIPH_I2C4_TX    = 57,
+  DMA2_PERIPH_ADC1       = 58,
+  DMA2_PERIPH_ADC2       = 59,
+  DMA2_PERIPH_ADC3       = 60,
+  DMA2_PERIPH_DCMI_1     = 61,
+  DMA_RESERVED(DMA2)     = 62,
+
+  DMA2_PERIPH_SAI1_A_1   = 63,
+  DMA2_PERIPH_SAI1_B_1   = 64,
+  DMA2_PERIPH_SAI2_A     = 65,
+  DMA2_PERIPH_SAI2_B     = 66,
+  DMA_RESERVED(DMA2)     = 67,
+  DMA2_PERIPH_SAI1_A_2   = 68,
+  DMA2_PERIPH_SAI1_B_2   = 69,
+
+  DMA2_PERIPH_UART5_TX   = 70,
+  DMA2_PERIPH_UART5_RX   = 71,
+  DMA2_PERIPH_UART4_TX   = 72,
+  DMA_RESERVED(DMA2)     = 73,
+  DMA2_PERIPH_UART4_RX   = 74,
+  DMA2_PERIPH_USART1_TX  = 75,
+  DMA2_PERIPH_USART1_RX  = 76,
+
+  DMA2_PERIPH_SPI3_RX    = 77,
+  DMA2_PERIPH_SPI3_TX    = 78,
+  DMA_RESERVED(DMA2)     = 79,
+  DMA2_PERIPH_TIM6_UP    = 80,
+  DMA2_PERIPH_DAC_CH1    = 80 | ALTERNATE1, /* Same as TIM6_UP */
+  DMA2_PERIPH_TIM7_UP    = 81,
+  DMA2_PERIPH_DAC_CH2    = 81 | ALTERNATE1, /* Same as TIM7_UP */
+  DMA_RESERVED(DMA2)     = 82,
+  DMA2_PERIPH_QUADSPI    = 83,
+
+  DMA2_PERIPH_SWPMI1_RX  = 84,
+  DMA2_PERIPH_SWPMI1_TX  = 85,
+  DMA2_PERIPH_SPI1_RX    = 86,
+  DMA2_PERIPH_SPI1_TX    = 87,
+  DMA2_PERIPH_DCMI_2     = 88,
+  DMA2_PERIPH_LPUART1_TX = 89,
+  DMA2_PERIPH_LPUART1_RX = 90,
+
+
+  DMA2_PERIPH_TIM5_CH4   = 91,
+  DMA2_PERIPH_TIM5_TRIG  = 91 | ALTERNATE1, /* Same as TIM5_CH4 */
+  DMA2_PERIPH_TIM5_CH3   = 92,
+  DMA2_PERIPH_TIM5_UP    = 92 | ALTERNATE1, /* Same as TIM5_CH3 */
+  DMA_RESERVED(DMA2)     = 93,
+  DMA2_PERIPH_TIM5_CH2   = 94,
+  DMA2_PERIPH_TIM5_CH1   = 95,
+  DMA2_PERIPH_I2C1_RX    = 96,
+  DMA2_PERIPH_I2C1_TX    = 97,
+
+  DMA2_PERIPH_AES_IN_1   = 98,
+  DMA2_PERIPH_AES_OUT_1  = 99,
+  DMA2_PERIPH_AES_OUT_2  = 100,
+  DMA_RESERVED(DMA2)     = 101,
+  DMA2_PERIPH_AES_IN_2   = 102,
+  DMA_RESERVED(DMA2)     = 103,
+  DMA2_PERIPH_HASH_IN    = 104,
+
+  DMA2_PERIPH_TIM8_CH3   = 105,
+  DMA2_PERIPH_TIM8_UP    = 105 | ALTERNATE1, /* Same as TIM8_CH3 */
+  DMA2_PERIPH_TIM8_CH4   = 106,
+  DMA2_PERIPH_TIM8_TRIG  = 106 | ALTERNATE1, /* Same as TIM8_CH4 */
+  DMA2_PERIPH_TIM8_COM   = 106 | ALTERNATE2, /* Same as TIM8_CH4 */
+  DMA_RESERVED(DMA2)     = 107,
+  DMA2_PERIPH_SDMMC1_1   = 108,
+  DMA2_PERIPH_SDMMC1_2   = 109,
+  DMA2_PERIPH_TIM8_CH1   = 110,
+  DMA2_PERIPH_TIM8_CH2   = 111,
+
+
+  DMA_PERIPH_SENTINEL,
+} dma_peripheral_t;
+
+
+/* Defines a DMA channel. */
+typedef struct {
+  uint8_t dma; /* 0 = DMA1, 1 = DMA2 */
+  uint8_t chan; /* 0 - 6 */
+} dma_channel_t;
+
+
+/*
+ * Defines a DMA channel allocated for memory-to-peripheral transfers.  This
+ * structure is only nominally different from dma_channel_t in order to provide
+ * rudimentary type-checking.
+ */
+typedef struct {
+  dma_channel_t c_;
+} dma_mem2p_channel_t;
+
+/*
+ * Defines a DMA channel allocated for peripheral-to-memory transfers.  This
+ * structure is only nominally different from dma_channel_t in order to provide
+ * rudimentary type-checking.
+ */
+typedef struct {
+  dma_channel_t c_;
+} dma_p2mem_channel_t;
+
+/* Defines a DMA channel allocated for mem2mem transfers.
+ * This structure is only nominally different from dma_channel_t
+ * in order to provide rudimentary type-checking.
+ */
+typedef struct {
+  dma_channel_t c_;
+} dma_mem2mem_channel_t;
+
+#define DMA_CHAN_ERROR ((dma_channel_t) { .dma = 0xff, .chan = 0xff })
+
+typedef struct {
+  bool transfer_complete_interrupt_enable;
+  bool half_transfer_interrupt_enable;
+  bool transfer_error_interrupt_enable;
+
+  bool circular_mode;
+  bool peripheral_increment;
+  bool memory_increment;
+
+  dma_size_t peripheral_block_size;
+  dma_size_t memory_block_size;
+
+  dma_priority_level_t priority;
+} dma_opts_t;
+
+#define DEFAULT_DMA_OPTS \
+  ((dma_opts_t) { .memory_increment = 1, \
+                  .peripheral_increment = 0, \
+                  .transfer_complete_interrupt_enable = 0, \
+                  .half_transfer_interrupt_enable = 0, \
+                  .transfer_error_interrupt_enable = 0, \
+                  .circular_mode = 0, \
+                  .peripheral_block_size = DMA_SIZE_8_BITS, \
+                  .memory_block_size = DMA_SIZE_8_BITS, \
+                  .priority = DMA_PRIORITY_LEVEL_MEDIUM })
+
+dma_p2mem_channel_t select_dma_channel_p2mem(
+    dma_peripheral_t peripheral,
+    dma_opts_t* opts_in,
+    int* error);
+
+dma_mem2p_channel_t select_dma_channel_mem2p(
+    dma_peripheral_t peripheral,
+    dma_opts_t* opts_in,
+    int* error);
+
+/* Returns a dma channel used for memory-to-memory transfers.
+ *
+ * channel - the channel this dma should use. The channel should
+ * be on the range [0-13]. The channels [0-6] refer to the 7 channels
+ * on DMA1, where channels [7-13] refer to the 7 channels on DMA2.
+ * 
+ * If `channel` is -1, then the highest unused dma channel is selected.
+ */
+dma_mem2mem_channel_t select_dma_channel_mem2mem(
+    int channel,
+    dma_opts_t* opts,
+    int* error_out);
+
+void dma_mem2p_initiate_transfer(
+    dma_mem2p_channel_t chan, const void* from_loc, uint16_t nblocks);
+
+void dma_p2mem_initiate_transfer(
+    dma_p2mem_channel_t chan, void* to_loc, uint16_t nblocks);
+
+void dma_mem2mem_initiate_transfer(
+    dma_mem2mem_channel_t chan,
+    void* to_loc,
+    const void* from_loc,
+    uint16_t nblocks);
+
+void release_dma_channel(dma_channel_t chan);
+
+interrupt_t dma_channel_get_interrupt(dma_channel_t chan);
+
+#endif
diff --git a/02-usart/include/kern/lib.h b/02-usart/include/kern/lib.h
new file mode 100644
index 0000000..be0e8e9
--- /dev/null
+++ b/02-usart/include/kern/lib.h
@@ -0,0 +1,10 @@
+#ifndef LIB_H_
+#define LIB_H_
+
+#include <stdint.h>
+
+void hexify(uint32_t v, char* into);
+
+void decimalify(int v, char* into);
+
+#endif
diff --git a/02-usart/include/kern/mem.h b/02-usart/include/kern/mem.h
new file mode 100644
index 0000000..d150744
--- /dev/null
+++ b/02-usart/include/kern/mem.h
@@ -0,0 +1,30 @@
+#ifndef MEM_H_
+#define MEM_H_
+
+#include "arch.h"
+#include <stddef.h>
+
+#define DATA_SEGMENT_STOP_ADDR ((uint8_t*) &DATA_SEGMENT_STOP)
+#define DATA_SEGMENT_START_ADDR ((uint8_t*) &DATA_SEGMENT_START)
+
+#define MAX_HEAP_SIZE \
+  ((16384 - (DATA_SEGMENT_STOP_ADDR - DATA_SEGMENT_START_ADDR)) / 4 * 4)
+
+/* allocates memory on the head, which is stored in sram2 */
+void* halloc(size_t n);
+
+/* Frees the memory allocated by halloc. */
+void hfree(void* mem);
+
+#ifdef FOR_TESTING
+
+void* debug_halloc_get_next_ptr(void* ptr);
+
+void* debug_halloc_get_prev_ptr(void* ptr);
+
+int debug_halloc_assert_consistency(char* error, size_t len);
+
+#endif
+
+
+#endif
diff --git a/02-usart/include/kern/spin.h b/02-usart/include/kern/spin.h
new file mode 100644
index 0000000..a23d25b
--- /dev/null
+++ b/02-usart/include/kern/spin.h
@@ -0,0 +1,15 @@
+#ifndef H__SPIN_
+#define H__SPIN_
+
+#include <stdint.h>
+
+/*
+ * Flash a code on the status LED.
+ *
+ * The flash codes a binary from MSB to LSB. A long flash is a 1, a short flash
+ * is a 0. Each independent flashing is succeced by a break of 4 times that
+ * of a long flash.
+ */
+void spin(uint32_t base_delay, uint8_t code);
+
+#endif /* H__SPIN_ */
diff --git a/02-usart/include/kern/string.h b/02-usart/include/kern/string.h
new file mode 100644
index 0000000..3c9f0b4
--- /dev/null
+++ b/02-usart/include/kern/string.h
@@ -0,0 +1,6 @@
+#ifndef STRING_H_
+#define STRING_H_
+
+void kstrcpy(char* into, const char* from);
+
+#endif /* STRING_H_ */