From 31bc2c9bcd3054b90322acf85a53aacbb9e29ee4 Mon Sep 17 00:00:00 2001 From: Rui Miguel Silva Date: Wed, 2 Dec 2015 11:12:29 +0000 Subject: [PATCH] greybus: spi: fix transfers bigger than greybus payload Add helper functions calculate the tx and rx size possible that fit a greybus payload size and change the operation creation to adjust to that. Signed-off-by: Rui Miguel Silva Signed-off-by: Greg Kroah-Hartman --- drivers/staging/greybus/spi.c | 102 +++++++++++++++++++++++++++++----- 1 file changed, 87 insertions(+), 15 deletions(-) diff --git a/drivers/staging/greybus/spi.c b/drivers/staging/greybus/spi.c index 8e0e403795f4..094d6d8c4f34 100644 --- a/drivers/staging/greybus/spi.c +++ b/drivers/staging/greybus/spi.c @@ -31,6 +31,51 @@ static struct spi_master *get_master_from_spi(struct gb_spi *spi) return spi->connection->private; } +static int tx_header_fit_operation(u32 tx_size, u32 count, size_t data_max) +{ + size_t headers_size; + + data_max -= sizeof(struct gb_spi_transfer_request); + headers_size = (count + 1) * sizeof(struct gb_spi_transfer); + + return tx_size + headers_size > data_max ? 0 : 1; +} + +static size_t calc_rx_xfer_size(u32 rx_size, u32 *tx_xfer_size, u32 len, + size_t data_max) +{ + size_t rx_xfer_size; + + data_max -= sizeof(struct gb_spi_transfer_response); + + if (rx_size + len > data_max) + rx_xfer_size = data_max - rx_size; + else + rx_xfer_size = len; + + /* if this is a write_read, for symmetry read the same as write */ + if (*tx_xfer_size && rx_xfer_size > *tx_xfer_size) + rx_xfer_size = *tx_xfer_size; + if (*tx_xfer_size && rx_xfer_size < *tx_xfer_size) + *tx_xfer_size = rx_xfer_size; + + return rx_xfer_size; +} + +static size_t calc_tx_xfer_size(u32 tx_size, u32 count, size_t len, + size_t data_max) +{ + size_t headers_size; + + data_max -= sizeof(struct gb_spi_transfer_request); + headers_size = (count + 1) * sizeof(struct gb_spi_transfer); + + if (tx_size + headers_size + len > data_max) + return data_max - (tx_size + sizeof(struct gb_spi_transfer)); + + return len; +} + /* Routines to transfer data */ static struct gb_operation * gb_spi_operation_create(struct gb_connection *connection, @@ -41,9 +86,14 @@ gb_spi_operation_create(struct gb_connection *connection, struct spi_transfer *xfer; struct gb_spi_transfer *gb_xfer; struct gb_operation *operation; - u32 tx_size = 0, rx_size = 0, count = 0, request_size; + struct spi_transfer *last_xfer = NULL; + u32 tx_size = 0, rx_size = 0, count = 0, xfer_len = 0, request_size; + u32 tx_xfer_size = 0, rx_xfer_size = 0, last_xfer_size = 0; + size_t data_max; void *tx_data; + data_max = gb_operation_get_payload_size_max(connection); + /* Find number of transfers queued and tx/rx length in the message */ list_for_each_entry(xfer, &msg->transfers, transfer_list) { if (!xfer->tx_buf && !xfer->rx_buf) { @@ -51,21 +101,33 @@ gb_spi_operation_create(struct gb_connection *connection, "bufferless transfer, length %u\n", xfer->len); return NULL; } + last_xfer = xfer; - if (xfer->tx_buf) - tx_size += xfer->len; - if (xfer->rx_buf) - rx_size += xfer->len; + tx_xfer_size = 0; + rx_xfer_size = 0; + + if (xfer->tx_buf) { + if (!tx_header_fit_operation(tx_size, count, data_max)) + break; + tx_xfer_size = calc_tx_xfer_size(tx_size, count, + xfer->len, data_max); + last_xfer_size = tx_xfer_size; + } + + if (xfer->rx_buf) { + rx_xfer_size = calc_rx_xfer_size(rx_size, &tx_xfer_size, + xfer->len, data_max); + last_xfer_size = rx_xfer_size; + } + + tx_size += tx_xfer_size; + rx_size += rx_xfer_size; - *total_len += xfer->len; + *total_len += last_xfer_size; count++; - } - /* Too many transfers ? */ - if (count > (u32)U16_MAX) { - dev_err(&connection->bundle->dev, - "transfer count (%u) too big\n", count); - return NULL; + if (xfer->len != last_xfer_size) + break; } /* @@ -92,20 +154,30 @@ gb_spi_operation_create(struct gb_connection *connection, /* Fill in the transfers array */ list_for_each_entry(xfer, &msg->transfers, transfer_list) { + if (last_xfer && xfer == last_xfer) + xfer_len = last_xfer_size; + else + xfer_len = xfer->len; + gb_xfer->speed_hz = cpu_to_le32(xfer->speed_hz); - gb_xfer->len = cpu_to_le32(xfer->len); + gb_xfer->len = cpu_to_le32(xfer_len); gb_xfer->delay_usecs = cpu_to_le16(xfer->delay_usecs); gb_xfer->cs_change = xfer->cs_change; gb_xfer->bits_per_word = xfer->bits_per_word; /* Copy tx data */ if (xfer->tx_buf) { - memcpy(tx_data, xfer->tx_buf, xfer->len); - tx_data += xfer->len; gb_xfer->rdwr |= GB_SPI_XFER_WRITE; + memcpy(tx_data, xfer->tx_buf, xfer_len); + tx_data += xfer_len; } + if (xfer->rx_buf) gb_xfer->rdwr |= GB_SPI_XFER_READ; + + if (last_xfer && xfer == last_xfer) + break; + gb_xfer++; } -- 2.20.1