1* Device tree bindings for Texas instruments AEMIF controller 2 3The Async External Memory Interface (EMIF16/AEMIF) controller is intended to 4provide a glue-less interface to a variety of asynchronous memory devices like 5ASRA M, NOR and NAND memory. A total of 256M bytes of any of these memories 6can be accessed at any given time via four chip selects with 64M byte access 7per chip select. Synchronous memories such as DDR1 SD RAM, SDR SDRAM 8and Mobile SDR are not supported. 9 10Documentation: 11Davinci DM646x - http://www.ti.com/lit/ug/sprueq7c/sprueq7c.pdf 12OMAP-L138 (DA850) - http://www.ti.com/lit/ug/spruh77a/spruh77a.pdf 13Kestone - http://www.ti.com/lit/ug/sprugz3a/sprugz3a.pdf 14 15Required properties: 16 17- compatible: "ti,davinci-aemif" 18 "ti,keystone-aemif" 19 "ti,da850-aemif" 20 21- reg: contains offset/length value for AEMIF control registers 22 space. 23 24- #address-cells: Must be 2. The partition number has to be encoded in the 25 first address cell and it may accept values 0..N-1 26 (N - total number of partitions). It's recommended to 27 assign N-1 number for the control partition. The second 28 cell is the offset into the partition. 29 30- #size-cells: Must be set to 1. 31 32- ranges: Contains memory regions. There are two types of 33 ranges/partitions: 34 - CS-specific partition/range. If continuous, must be 35 set up to reflect the memory layout for 4 chipselects, 36 if not then additional range/partition can be added and 37 child device can select the proper one. 38 - control partition which is common for all CS 39 interfaces. 40 41- clocks: the clock feeding the controller clock. Required only 42 if clock tree data present in device tree. 43 See clock-bindings.txt 44 45- clock-names: clock name. It has to be "aemif". Required only if clock 46 tree data present in device tree, in another case don't 47 use it. 48 See clock-bindings.txt 49 50- clock-ranges: Empty property indicating that child nodes can inherit 51 named clocks. Required only if clock tree data present 52 in device tree. 53 See clock-bindings.txt 54 55 56Child chip-select (cs) nodes contain the memory devices nodes connected to 57such as NOR (e.g. cfi-flash) and NAND (ti,davinci-nand, see davinci-nand.txt). 58There might be board specific devices like FPGAs. 59 60Required child cs node properties: 61 62- #address-cells: Must be 2. 63 64- #size-cells: Must be 1. 65 66- ranges: Empty property indicating that child nodes can inherit 67 memory layout. 68 69- clock-ranges: Empty property indicating that child nodes can inherit 70 named clocks. Required only if clock tree data present 71 in device tree. 72 73- ti,cs-chipselect: number of chipselect. Indicates on the aemif driver 74 which chipselect is used for accessing the memory. For 75 compatibles "ti,davinci-aemif" and "ti,keystone-aemif" 76 it can be in range [0-3]. For compatible 77 "ti,da850-aemif" range is [2-5]. 78 79Optional child cs node properties: 80 81- ti,cs-bus-width: width of the asynchronous device's data bus 82 8 or 16 if not preset 8 83 84- ti,cs-select-strobe-mode: enable/disable select strobe mode 85 In select strobe mode chip select behaves as 86 the strobe and is active only during the strobe 87 period. If present then enable. 88 89- ti,cs-extended-wait-mode: enable/disable extended wait mode 90 if set, the controller monitors the EMIFWAIT pin 91 mapped to that chip select to determine if the 92 device wants to extend the strobe period. If 93 present then enable. 94 95- ti,cs-min-turnaround-ns: minimum turn around time, ns 96 Time between the end of one asynchronous memory 97 access and the start of another asynchronous 98 memory access. This delay is not incurred 99 between a read followed by read or a write 100 followed by a write to same chip select. 101 102- ti,cs-read-setup-ns: read setup width, ns 103 Time between the beginning of a memory cycle 104 and the activation of read strobe. 105 Minimum value is 1 (0 treated as 1). 106 107- ti,cs-read-strobe-ns: read strobe width, ns 108 Time between the activation and deactivation of 109 the read strobe. 110 Minimum value is 1 (0 treated as 1). 111 112- ti,cs-read-hold-ns: read hold width, ns 113 Time between the deactivation of the read 114 strobe and the end of the cycle (which may be 115 either an address change or the deactivation of 116 the chip select signal. 117 Minimum value is 1 (0 treated as 1). 118 119- ti,cs-write-setup-ns: write setup width, ns 120 Time between the beginning of a memory cycle 121 and the activation of write strobe. 122 Minimum value is 1 (0 treated as 1). 123 124- ti,cs-write-strobe-ns: write strobe width, ns 125 Time between the activation and deactivation of 126 the write strobe. 127 Minimum value is 1 (0 treated as 1). 128 129- ti,cs-write-hold-ns: write hold width, ns 130 Time between the deactivation of the write 131 strobe and the end of the cycle (which may be 132 either an address change or the deactivation of 133 the chip select signal. 134 Minimum value is 1 (0 treated as 1). 135 136If any of the above parameters are absent, current parameter value will be taken 137from the corresponding HW reg. 138 139Example for aemif, davinci nand and nor flash chip select shown below. 140 141memory-controller@21000a00 { 142 compatible = "ti,davinci-aemif"; 143 #address-cells = <2>; 144 #size-cells = <1>; 145 clocks = <&clkaemif 0>; 146 clock-names = "aemif"; 147 clock-ranges; 148 reg = <0x21000A00 0x00000100>; 149 ranges = <0 0 0x70000000 0x10000000 150 1 0 0x21000A00 0x00000100>; 151 /* 152 * Partition0: CS-specific memory range which is 153 * implemented as continuous physical memory region 154 * Partition1: control memory range 155 */ 156 157 nand:cs2 { 158 #address-cells = <2>; 159 #size-cells = <1>; 160 clock-ranges; 161 ranges; 162 163 ti,cs-chipselect = <2>; 164 /* all timings in nanoseconds */ 165 ti,cs-min-turnaround-ns = <0>; 166 ti,cs-read-hold-ns = <7>; 167 ti,cs-read-strobe-ns = <42>; 168 ti,cs-read-setup-ns = <14>; 169 ti,cs-write-hold-ns = <7>; 170 ti,cs-write-strobe-ns = <42>; 171 ti,cs-write-setup-ns = <14>; 172 173 nand@0,0x8000000 { 174 compatible = "ti,davinci-nand"; 175 reg = <0 0x8000000 0x4000000 176 1 0x0000000 0x0000100>; 177 /* 178 * Partition0, offset 0x8000000, size 0x4000000 179 * Partition1, offset 0x0000000, size 0x0000100 180 */ 181 182 .. see davinci-nand.txt 183 }; 184 }; 185 186 nor:cs0 { 187 #address-cells = <2>; 188 #size-cells = <1>; 189 clock-ranges; 190 ranges; 191 192 ti,cs-chipselect = <0>; 193 /* all timings in nanoseconds */ 194 ti,cs-min-turnaround-ns = <0>; 195 ti,cs-read-hold-ns = <8>; 196 ti,cs-read-strobe-ns = <40>; 197 ti,cs-read-setup-ns = <14>; 198 ti,cs-write-hold-ns = <7>; 199 ti,cs-write-strobe-ns = <40>; 200 ti,cs-write-setup-ns = <14>; 201 ti,cs-bus-width = <16>; 202 203 flash@0,0x0000000 { 204 compatible = "cfi-flash"; 205 reg = <0 0x0000000 0x4000000>; 206 207 ... 208 }; 209 }; 210}; 211