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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 <rui.silva@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:
Rui Miguel Silva 2015-12-02 11:12:29 +00:00 committed by Greg Kroah-Hartman
parent 11aa7121ed
commit 31bc2c9bcd
1 changed files with 87 additions and 15 deletions
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102
drivers/staging/greybus/spi.c
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@ -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;
*total_len += xfer->len;
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 += 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++;
}