Merge branch 'lukeshu/iov'

1 files changed, 100 insertions, 41 deletions

diff --git a/libhw/w5500_ll.h b/libhw/w5500_ll.h
index 92d9f14..cad20a4 100644
--- a/libhw/w5500_ll.h
+++ b/libhw/w5500_ll.h
@@ -10,6 +10,7 @@
 #ifndef _LIBHW_W5500_LL_H_
 #define _LIBHW_W5500_LL_H_
 
+#include <alloca.h> /* for alloca() */
 #include <stdint.h> /* for uint{n}_t */
 #include <string.h> /* for memcmp() */
 
@@ -68,62 +69,111 @@ static char *_ctl_block_part_strs[] = {
 
 static inline void
 #if CONFIG_W5500_LL_DEBUG
-#define w5500ll_write(...) _w5500ll_write(__func__, __VA_ARGS__)
-_w5500ll_write(const char *func,
+#define w5500ll_writev(...) _w5500ll_writev(__func__, __VA_ARGS__)
+_w5500ll_writev(const char *func,
 #else
-w5500ll_write(
+w5500ll_writev(
 #endif
-              lo_interface spi spidev, uint16_t addr, uint8_t block, void *data, size_t data_len) {
+               lo_interface spi spidev, uint16_t addr, uint8_t block,
+               const struct iovec *iov, int iovcnt,
+               size_t skip, size_t max)
+{
 	assert(!LO_IS_NULL(spidev));
 	assert((block & ~CTL_MASK_BLOCK) == 0);
-	assert(data);
-	assert(data_len);
+	assert(iov);
+	assert(iovcnt > 0);
 #if CONFIG_W5500_LL_DEBUG
 	n_debugf(W5500_LL,
-	         "%s(): w5500ll_write(spidev, addr=%#04x, block="PRI_ctl_block", data, data_len=%zu)",
-	         func, addr, ARG_ctl_block(block), data_len);
+	         "%s(): w5500ll_write(spidev, addr=%#04x, block="PRI_ctl_block", iov, iovcnt=%d)",
+	         func, addr, ARG_ctl_block(block), iovcnt);
 #endif
 
-	uint8_t header[3] = {
+	uint8_t header[] = {
 		(uint8_t)((addr >> 8) & 0xFF),
 		(uint8_t)(addr & 0xFF),
 		(block & CTL_MASK_BLOCK) | CTL_W | CTL_OM_VDM,
 	};
-	struct bidi_iovec iov[] = {
-		{.iov_read_dst = NULL, .iov_write_src = header, .iov_len = sizeof(header)},
-		{.iov_read_dst = NULL, .iov_write_src = data,   .iov_len = data_len},
+	struct duplex_iovec *inner = alloca(sizeof(struct duplex_iovec)*(iovcnt+1));
+	inner[0] = (struct duplex_iovec){
+		.iov_read_dst  = NULL,
+		.iov_write_src = header,
+		.iov_len       = sizeof(header),
 	};
-	LO_CALL(spidev, readwritev, iov, 2);
+	int j = 1;
+	size_t skipped = 0, done = 0;
+	for (int i = 0; i < iovcnt && (max == 0 || done < max); i++) {
+		if (skipped < skip) {
+			if (skip - skipped >= iov[i].iov_len) {
+				skipped += iov[i].iov_len;
+				continue;
+			}
+			inner[j] = (struct duplex_iovec){
+				.iov_read_dst  = NULL,
+				.iov_write_src = iov[i].iov_base+(skipped-skip),
+				.iov_len       = iov[i].iov_len-(skipped-skip),
+			};
+			skipped = skip;
+		} else {
+			inner[j] = (struct duplex_iovec){
+				.iov_read_dst  = NULL,
+				.iov_write_src = iov[i].iov_base,
+				.iov_len       = iov[i].iov_len,
+			};
+		}
+		done += inner[j].iov_len;
+		if (max > 0 && done > max)
+			inner[j].iov_len -= done - max;
+		j++;
+	};
+	LO_CALL(spidev, readwritev, inner, j);
 }
 
 static inline void
 #if CONFIG_W5500_LL_DEBUG
-#define w5500ll_read(...) _w5500ll_read(__func__, __VA_ARGS__)
-_w5500ll_read(const char *func,
+#define w5500ll_readv(...) _w5500ll_read(__func__, __VA_ARGS__)
+_w5500ll_readv(const char *func,
 #else
-w5500ll_read(
+w5500ll_readv(
 #endif
-              lo_interface spi spidev, uint16_t addr, uint8_t block, void *data, size_t data_len) {
+              lo_interface spi spidev, uint16_t addr, uint8_t block,
+              const struct iovec *iov, int iovcnt,
+              size_t max)
+{
 	assert(!LO_IS_NULL(spidev));
 	assert((block & ~CTL_MASK_BLOCK) == 0);
-	assert(data);
-	assert(data_len);
+	assert(iov);
+	assert(iovcnt > 0);
 #if CONFIG_W5500_LL_DEBUG
 	n_debugf(W5500_LL,
-	         "%s(): w5500ll_read(spidev, addr=%#04x, block="PRI_ctl_block", data, data_len=%zu)",
-	         func, addr, ARG_ctl_block(block), data_len);
+	         "%s(): w5500ll_read(spidev, addr=%#04x, block="PRI_ctl_block", iov, iovcnt=%d)",
+	         func, addr, ARG_ctl_block(block), iovcnt);
 #endif
 
-	uint8_t header[3] = {
+	uint8_t header[] = {
 		(uint8_t)((addr >> 8) & 0xFF),
 		(uint8_t)(addr & 0xFF),
 		(block & CTL_MASK_BLOCK) | CTL_R | CTL_OM_VDM,
 	};
-	struct bidi_iovec iov[] = {
-		{.iov_read_dst = NULL, .iov_write_src = header, .iov_len = sizeof(header)},
-		{.iov_read_dst = data, .iov_write_src = NULL,   .iov_len = data_len},
+	struct duplex_iovec *inner = alloca(sizeof(struct duplex_iovec)*(iovcnt+1));
+	inner[0] = (struct duplex_iovec){
+		.iov_read_dst  = NULL,
+		.iov_write_src = header,
+		.iov_len       = sizeof(header),
+	};
+	int j = 1;
+	size_t done = 0;
+	for (int i = 0; i < iovcnt && (max == 0 || done < max); i++) {
+		inner[j] = (struct duplex_iovec){
+			.iov_read_dst  = iov[i].iov_base,
+			.iov_write_src = NULL,
+			.iov_len       = iov[i].iov_len,
+		};
+		done += inner[j].iov_len;
+		if (max > 0 && done > max)
+			inner[j].iov_len -= done - max;
+		j++;
 	};
-	LO_CALL(spidev, readwritev, iov, 2);
+	LO_CALL(spidev, readwritev, inner, j);
 }
 
 /* Common chip-wide registers.  ***********************************************/
@@ -367,11 +417,14 @@ static_assert(sizeof(struct w5500ll_block_sock_reg) == 0x30);
 
 #define w5500ll_write_reg(spidev, blockid, blocktyp, field, val) do { \
 		typeof((blocktyp){}.field) lval = val;                \
-		w5500ll_write(spidev,                                 \
-		                     offsetof(blocktyp, field),       \
-		                     blockid,                         \
-		                     &lval,                           \
-		                     sizeof(lval));                   \
+		w5500ll_writev(spidev,                                \
+			offsetof(blocktyp, field),                    \
+			blockid,                                      \
+			&((struct iovec){                             \
+				&lval,                                \
+				sizeof(lval),                         \
+			}),                                           \
+			1, 0, 0);                                     \
 	} while (0)
 
 /* The datasheet tells us that multi-byte reads are non-atomic and
@@ -379,19 +432,25 @@ static_assert(sizeof(struct w5500ll_block_sock_reg) == 0x30);
  * until getting the same value".  */
 #define w5500ll_read_reg(spidev, blockid, blocktyp, field) ({              \
 		typeof((blocktyp){}.field) val;                            \
-		w5500ll_read(spidev,                                       \
-		             offsetof(blocktyp, field),                    \
-		             blockid,                                      \
-		             &val,                                         \
-		             sizeof(val));                                 \
+		w5500ll_readv(spidev,                                      \
+			offsetof(blocktyp, field),                         \
+			blockid,                                           \
+			&((struct iovec){                                  \
+				.iov_base = &val,                          \
+				.iov_len = sizeof(val),                    \
+			}),                                                \
+			1, 0);                                             \
 		if (sizeof(val) > 1)                                       \
 			for (;;) {                                         \
 				typeof(val) val2;                          \
-				w5500ll_read(spidev,                       \
-				             offsetof(blocktyp, field),    \
-				             blockid,                      \
-				             &val2,                        \
-				             sizeof(val));                 \
+				w5500ll_readv(spidev,                      \
+					offsetof(blocktyp, field),         \
+					blockid,                           \
+					&((struct iovec){                  \
+						.iov_base = &val2,         \
+						.iov_len = sizeof(val),    \
+					}),                                \
+					1, 0);                             \
 				if (memcmp(&val2, &val, sizeof(val)) == 0) \
 					break;                             \
 				val = val2;                                \