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authorTejun Heo <htejun@gmail.com>2008-03-24 23:22:49 -0400
committerJeff Garzik <jgarzik@redhat.com>2008-04-17 15:44:17 -0400
commit029cfd6b74fc5c517865fad78cf4a3ea8d9b664a (patch)
tree4a40f44f29321e433497a51d2f6cfe1922ae1d58 /drivers/ata/pata_ns87415.c
parent68d1d07b510bb57a504588adc2bd2758adea0965 (diff)
libata: implement and use ops inheritance
libata lets low level drivers build ata_port_operations table and register it with libata core layer. This allows low level drivers high level of flexibility but also burdens them with lots of boilerplate entries. This becomes worse for drivers which support related similar controllers which differ slightly. They share most of the operations except for a few. However, the driver still needs to list all operations for each variant. This results in large number of duplicate entries, which is not only inefficient but also error-prone as it becomes very difficult to tell what the actual differences are. This duplicate boilerplates all over the low level drivers also make updating the core layer exteremely difficult and error-prone. When compounded with multi-branched development model, it ends up accumulating inconsistencies over time. Some of those inconsistencies cause immediate problems and fixed. Others just remain there dormant making maintenance increasingly difficult. To rectify the problem, this patch implements ata_port_operations inheritance. To allow LLDs to easily re-use their own ops tables overriding only specific methods, this patch implements poor man's class inheritance. An ops table has ->inherits field which can be set to any ops table as long as it doesn't create a loop. When the host is started, the inheritance chain is followed and any operation which isn't specified is taken from the nearest ancestor which has it specified. This operation is called finalization and done only once per an ops table and the LLD doesn't have to do anything special about it other than making the ops table non-const such that libata can update it. libata provides four base ops tables lower drivers can inherit from - base, sata, pmp, sff and bmdma. To avoid overriding these ops accidentaly, these ops are declared const and LLDs should always inherit these instead of using them directly. After finalization, all the ops table are identical before and after the patch except for setting .irq_handler to ata_interrupt in drivers which didn't use to. The .irq_handler doesn't have any actual effect and the field will soon be removed by later patch. * sata_sx4 is still using old style EH and currently doesn't take advantage of ops inheritance. Signed-off-by: Tejun Heo <htejun@gmail.com>
Diffstat (limited to 'drivers/ata/pata_ns87415.c')
-rw-r--r--drivers/ata/pata_ns87415.c68
1 files changed, 12 insertions, 56 deletions
diff --git a/drivers/ata/pata_ns87415.c b/drivers/ata/pata_ns87415.c
index 78d634423cbf..38d86a262dbb 100644
--- a/drivers/ata/pata_ns87415.c
+++ b/drivers/ata/pata_ns87415.c
@@ -297,73 +297,29 @@ static u8 ns87560_bmdma_status(struct ata_port *ap)
297{ 297{
298 return ns87560_read_buggy(ap->ioaddr.bmdma_addr + ATA_DMA_STATUS); 298 return ns87560_read_buggy(ap->ioaddr.bmdma_addr + ATA_DMA_STATUS);
299} 299}
300#endif /* 87560 SuperIO Support */
300 301
301static const struct ata_port_operations ns87560_pata_ops = { 302static struct ata_port_operations ns87415_pata_ops = {
302 .set_piomode = ns87415_set_piomode, 303 .inherits = &ata_bmdma_port_ops,
303 .mode_filter = ata_pci_default_filter,
304 304
305 .tf_load = ata_tf_load,
306 .tf_read = ns87560_tf_read,
307 .check_status = ns87560_check_status,
308 .check_atapi_dma = ns87415_check_atapi_dma, 305 .check_atapi_dma = ns87415_check_atapi_dma,
309 .exec_command = ata_exec_command,
310 .dev_select = ata_std_dev_select,
311
312 .freeze = ata_bmdma_freeze,
313 .thaw = ata_bmdma_thaw,
314 .error_handler = ata_bmdma_error_handler,
315 .post_internal_cmd = ata_bmdma_post_internal_cmd,
316 .cable_detect = ata_cable_40wire,
317
318 .bmdma_setup = ns87415_bmdma_setup, 306 .bmdma_setup = ns87415_bmdma_setup,
319 .bmdma_start = ns87415_bmdma_start, 307 .bmdma_start = ns87415_bmdma_start,
320 .bmdma_stop = ns87415_bmdma_stop, 308 .bmdma_stop = ns87415_bmdma_stop,
321 .bmdma_status = ns87560_bmdma_status,
322 .qc_prep = ata_qc_prep,
323 .qc_issue = ata_qc_issue_prot,
324 .data_xfer = ata_data_xfer,
325
326 .irq_handler = ata_interrupt,
327 .irq_clear = ns87415_bmdma_irq_clear, 309 .irq_clear = ns87415_bmdma_irq_clear,
328 .irq_on = ata_irq_on,
329
330 .port_start = ata_sff_port_start,
331};
332
333#endif /* 87560 SuperIO Support */
334
335
336static const struct ata_port_operations ns87415_pata_ops = {
337 .set_piomode = ns87415_set_piomode,
338 .mode_filter = ata_pci_default_filter,
339 310
340 .tf_load = ata_tf_load,
341 .tf_read = ata_tf_read,
342 .check_status = ata_check_status,
343 .check_atapi_dma = ns87415_check_atapi_dma,
344 .exec_command = ata_exec_command,
345 .dev_select = ata_std_dev_select,
346
347 .freeze = ata_bmdma_freeze,
348 .thaw = ata_bmdma_thaw,
349 .error_handler = ata_bmdma_error_handler,
350 .post_internal_cmd = ata_bmdma_post_internal_cmd,
351 .cable_detect = ata_cable_40wire, 311 .cable_detect = ata_cable_40wire,
312 .set_piomode = ns87415_set_piomode,
313};
352 314
353 .bmdma_setup = ns87415_bmdma_setup, 315#if defined(CONFIG_SUPERIO)
354 .bmdma_start = ns87415_bmdma_start, 316static struct ata_port_operations ns87560_pata_ops = {
355 .bmdma_stop = ns87415_bmdma_stop, 317 .inherits = &ns87415_pata_ops,
356 .bmdma_status = ata_bmdma_status, 318 .tf_read = ns87560_tf_read,
357 .qc_prep = ata_qc_prep, 319 .check_status = ns87560_check_status,
358 .qc_issue = ata_qc_issue_prot, 320 .bmdma_status = ns87560_bmdma_status,
359 .data_xfer = ata_data_xfer,
360
361 .irq_handler = ata_interrupt,
362 .irq_clear = ns87415_bmdma_irq_clear,
363 .irq_on = ata_irq_on,
364
365 .port_start = ata_sff_port_start,
366}; 321};
322#endif
367 323
368static struct scsi_host_template ns87415_sht = { 324static struct scsi_host_template ns87415_sht = {
369 ATA_BMDMA_SHT(DRV_NAME), 325 ATA_BMDMA_SHT(DRV_NAME),