path: root/drivers/char/xilinx_hwicap/xilinx_hwicap.c
diff options
authorStephen Neuendorffer <stephen.neuendorffer@xilinx.com>2008-03-18 04:36:31 +1100
committerJosh Boyer <jwboyer@linux.vnet.ibm.com>2008-03-26 07:27:21 -0500
commit4c58f8fe2e84ba76a4bef01cbd987b5ce62771c3 (patch)
tree6cad4a17085b51e29e757fdd0b39cca3775beb34 /drivers/char/xilinx_hwicap/xilinx_hwicap.c
parent6b06fdbaf9eb9f208a83540265a6a82bf1049a41 (diff)
[POWERPC] Xilinx: hwicap: Verify sync before reading idcode.
It appears that in some cases, the sync word might not be recognized by the hardware correctly. If this happens, then attempting to read from the port results in an unrecoverable error because of the design of the FPGA core. This patch updates the code to check the status of the device before reading the IDCODE, in order to avoid entering this unrecoverable state. This patch also adds additional NOOP commands into the sychronization sequence, which appears to be necessary to avoid the condition on some hardware. Signed-off-by: Stephen Neuendorffer <stephen.neuendorffer@xilinx.com> Acked-by: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Diffstat (limited to 'drivers/char/xilinx_hwicap/xilinx_hwicap.c')
1 files changed, 18 insertions, 0 deletions
diff --git a/drivers/char/xilinx_hwicap/xilinx_hwicap.c b/drivers/char/xilinx_hwicap/xilinx_hwicap.c
index 304727deaf3..5b8d6463e11 100644
--- a/drivers/char/xilinx_hwicap/xilinx_hwicap.c
+++ b/drivers/char/xilinx_hwicap/xilinx_hwicap.c
@@ -250,8 +250,26 @@ static int hwicap_get_configuration_register(struct hwicap_drvdata *drvdata,
* Create the data to be written to the ICAP.
buffer[index++] = XHI_DUMMY_PACKET;
+ buffer[index++] = XHI_NOOP_PACKET;
buffer[index++] = XHI_SYNC_PACKET;
buffer[index++] = XHI_NOOP_PACKET;
+ buffer[index++] = XHI_NOOP_PACKET;
+ /*
+ * Write the data to the FIFO and initiate the transfer of data present
+ * in the FIFO to the ICAP device.
+ */
+ status = drvdata->config->set_configuration(drvdata,
+ &buffer[0], index);
+ if (status)
+ return status;
+ /* If the syncword was not found, then we need to start over. */
+ status = drvdata->config->get_status(drvdata);
+ return -EIO;
+ index = 0;
buffer[index++] = hwicap_type_1_read(reg) | 1;
buffer[index++] = XHI_NOOP_PACKET;
buffer[index++] = XHI_NOOP_PACKET;