diff options
Diffstat (limited to 'Documentation/bus-devices/ti-gpmc.txt')
| -rw-r--r-- | Documentation/bus-devices/ti-gpmc.txt | 122 |
1 files changed, 0 insertions, 122 deletions
diff --git a/Documentation/bus-devices/ti-gpmc.txt b/Documentation/bus-devices/ti-gpmc.txt deleted file mode 100644 index cc9ce57e0a26..000000000000 --- a/Documentation/bus-devices/ti-gpmc.txt +++ /dev/null @@ -1,122 +0,0 @@ -GPMC (General Purpose Memory Controller): -========================================= - -GPMC is an unified memory controller dedicated to interfacing external -memory devices like - * Asynchronous SRAM like memories and application specific integrated - circuit devices. - * Asynchronous, synchronous, and page mode burst NOR flash devices - NAND flash - * Pseudo-SRAM devices - -GPMC is found on Texas Instruments SoC's (OMAP based) -IP details: http://www.ti.com/lit/pdf/spruh73 section 7.1 - - -GPMC generic timing calculation: -================================ - -GPMC has certain timings that has to be programmed for proper -functioning of the peripheral, while peripheral has another set of -timings. To have peripheral work with gpmc, peripheral timings has to -be translated to the form gpmc can understand. The way it has to be -translated depends on the connected peripheral. Also there is a -dependency for certain gpmc timings on gpmc clock frequency. Hence a -generic timing routine was developed to achieve above requirements. - -Generic routine provides a generic method to calculate gpmc timings -from gpmc peripheral timings. struct gpmc_device_timings fields has to -be updated with timings from the datasheet of the peripheral that is -connected to gpmc. A few of the peripheral timings can be fed either -in time or in cycles, provision to handle this scenario has been -provided (refer struct gpmc_device_timings definition). It may so -happen that timing as specified by peripheral datasheet is not present -in timing structure, in this scenario, try to correlate peripheral -timing to the one available. If that doesn't work, try to add a new -field as required by peripheral, educate generic timing routine to -handle it, make sure that it does not break any of the existing. -Then there may be cases where peripheral datasheet doesn't mention -certain fields of struct gpmc_device_timings, zero those entries. - -Generic timing routine has been verified to work properly on -multiple onenand's and tusb6010 peripherals. - -A word of caution: generic timing routine has been developed based -on understanding of gpmc timings, peripheral timings, available -custom timing routines, a kind of reverse engineering without -most of the datasheets & hardware (to be exact none of those supported -in mainline having custom timing routine) and by simulation. - -gpmc timing dependency on peripheral timings: -[<gpmc_timing>: <peripheral timing1>, <peripheral timing2> ...] - -1. common -cs_on: t_ceasu -adv_on: t_avdasu, t_ceavd - -2. sync common -sync_clk: clk -page_burst_access: t_bacc -clk_activation: t_ces, t_avds - -3. read async muxed -adv_rd_off: t_avdp_r -oe_on: t_oeasu, t_aavdh -access: t_iaa, t_oe, t_ce, t_aa -rd_cycle: t_rd_cycle, t_cez_r, t_oez - -4. read async non-muxed -adv_rd_off: t_avdp_r -oe_on: t_oeasu -access: t_iaa, t_oe, t_ce, t_aa -rd_cycle: t_rd_cycle, t_cez_r, t_oez - -5. read sync muxed -adv_rd_off: t_avdp_r, t_avdh -oe_on: t_oeasu, t_ach, cyc_aavdh_oe -access: t_iaa, cyc_iaa, cyc_oe -rd_cycle: t_cez_r, t_oez, t_ce_rdyz - -6. read sync non-muxed -adv_rd_off: t_avdp_r -oe_on: t_oeasu -access: t_iaa, cyc_iaa, cyc_oe -rd_cycle: t_cez_r, t_oez, t_ce_rdyz - -7. write async muxed -adv_wr_off: t_avdp_w -we_on, wr_data_mux_bus: t_weasu, t_aavdh, cyc_aavhd_we -we_off: t_wpl -cs_wr_off: t_wph -wr_cycle: t_cez_w, t_wr_cycle - -8. write async non-muxed -adv_wr_off: t_avdp_w -we_on, wr_data_mux_bus: t_weasu -we_off: t_wpl -cs_wr_off: t_wph -wr_cycle: t_cez_w, t_wr_cycle - -9. write sync muxed -adv_wr_off: t_avdp_w, t_avdh -we_on, wr_data_mux_bus: t_weasu, t_rdyo, t_aavdh, cyc_aavhd_we -we_off: t_wpl, cyc_wpl -cs_wr_off: t_wph -wr_cycle: t_cez_w, t_ce_rdyz - -10. write sync non-muxed -adv_wr_off: t_avdp_w -we_on, wr_data_mux_bus: t_weasu, t_rdyo -we_off: t_wpl, cyc_wpl -cs_wr_off: t_wph -wr_cycle: t_cez_w, t_ce_rdyz - - -Note: Many of gpmc timings are dependent on other gpmc timings (a few -gpmc timings purely dependent on other gpmc timings, a reason that -some of the gpmc timings are missing above), and it will result in -indirect dependency of peripheral timings to gpmc timings other than -mentioned above, refer timing routine for more details. To know what -these peripheral timings correspond to, please see explanations in -struct gpmc_device_timings definition. And for gpmc timings refer -IP details (link above). |